Keep the vcxproj source list alphabetical

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

.gitattributes

@@ -0,0 +1,3 @@
+# Resource scripts are Windows tooling input and must stay CRLF: the engine has no
+# encoding guard, so an autocrlf checkout could otherwise flatten them silently.
+*.rc text eol=crlf

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential clang autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev
 
       - name: Configure
         run: |
@@ -50,6 +50,9 @@ jobs:
           # committed generated files already let a plain checkout build.
           autoreconf -fi
           ./configure
+          # a missing decoder would silently drop the coding from Accept-Encoding
+          grep -q "define HTS_USEBROTLI 1" config.h
+          grep -q "define HTS_USEZSTD 1" config.h
 
       - name: Build
         run: make -j"$(nproc)"
@@ -82,7 +85,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev
 
       - name: Configure
         run: |
@@ -123,14 +126,18 @@ jobs:
       - name: Install build dependencies
         run: |
           set -euo pipefail
-          brew install autoconf automake libtool autoconf-archive
+          brew install autoconf automake libtool autoconf-archive brotli zstd
 
       - name: Configure
         run: |
           set -euo pipefail
           ssl="$(brew --prefix openssl@3)"
+          brewp="$(brew --prefix)"
           autoreconf -fi
-          ./configure CPPFLAGS="-I${ssl}/include" LDFLAGS="-L${ssl}/lib"
+          ./configure CPPFLAGS="-I${ssl}/include -I${brewp}/include" \
+            LDFLAGS="-L${ssl}/lib -L${brewp}/lib"
+          grep -q "define HTS_USEBROTLI 1" config.h
+          grep -q "define HTS_USEZSTD 1" config.h
 
       - name: Build
         run: make -j"$(sysctl -n hw.ncpu)"
@@ -166,14 +173,16 @@ jobs:
       - name: Install build dependencies
         run: |
           set -euo pipefail
-          brew install autoconf automake libtool autoconf-archive
+          brew install autoconf automake libtool autoconf-archive brotli zstd
 
       - name: Build and install into a temp prefix
         run: |
           set -euo pipefail
           ssl="$(brew --prefix openssl@3)"
+          brewp="$(brew --prefix)"
           autoreconf -fi
-          ./configure CPPFLAGS="-I${ssl}/include" LDFLAGS="-L${ssl}/lib" \
+          ./configure CPPFLAGS="-I${ssl}/include -I${brewp}/include" \
+            LDFLAGS="-L${ssl}/lib -L${brewp}/lib" \
             --prefix="$RUNNER_TEMP/inst"
           make -j"$(sysctl -n hw.ncpu)"
           make install
@@ -201,7 +210,8 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential gcc-multilib autoconf automake libtool \
-            autoconf-archive zlib1g-dev:i386 libssl-dev:i386
+            autoconf-archive zlib1g-dev:i386 libssl-dev:i386 \
+            libbrotli-dev:i386 libzstd-dev:i386
 
       - name: Configure
         run: |
@@ -242,7 +252,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev
 
       - name: Configure (sanitized)
         run: |
@@ -344,7 +354,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential clang autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev
 
       - name: Configure (fuzzers, static)
         run: |
@@ -424,7 +434,7 @@ jobs:
           apt-get install -y --no-install-recommends \
             ca-certificates git \
             build-essential autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev \
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev \
             debhelper devscripts lintian fakeroot
 
       - uses: actions/checkout@v6
@@ -468,7 +478,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
             build-essential autoconf automake libtool autoconf-archive \
-            zlib1g-dev libssl-dev
+            zlib1g-dev libssl-dev libbrotli-dev libzstd-dev
 
       - name: distcheck
         run: |

.github/workflows/windows-build.yml

@@ -119,6 +119,23 @@ jobs:
             throw "CRT mismatch across the boundary: libhttrack.dll=$a httrack.exe=$b"
           }
 
+      # The engine self-tests exercise the codecs the DLL was linked with: a
+      # missing brotli/zstd decoder shows up here, not just at link time.
+      - name: Run the content-coding self-tests
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = "Stop"
+          $exe = "src\${{ matrix.platform }}\${{ matrix.configuration }}\httrack.exe"
+          $tmp = New-Item -ItemType Directory -Path (Join-Path $env:RUNNER_TEMP "st")
+          foreach ($t in @("acceptencoding", "contentcodings")) {
+            $out = & $exe -O NUL "-#test=$t" $tmp.FullName run
+            if ($LASTEXITCODE -ne 0) { throw "$t failed" }
+            if (-not ($out | Select-String -SimpleMatch "$t self-test OK")) {
+              throw "$t did not report OK: $out"
+            }
+            Write-Host ($out -join "`n")
+          }
+
       - name: Upload MSBuild logs
         if: always()
         uses: actions/upload-artifact@v4

CLAUDE.local.md

@@ -0,0 +1 @@
+/home/roche/git/httrack-works/CLAUDE.httrack.local.md

configure.ac

@@ -173,6 +173,10 @@ AC_CHECK_HEADERS([execinfo.h])
 ### zlib
 CHECK_ZLIB()
 
+### brotli and zstd content codings (optional)
+CHECK_BROTLI()
+CHECK_ZSTD()
+
 ### OpenSSL is explicitly enabled/disabled ?
 AC_MSG_CHECKING(whether to enable https support)
 AC_ARG_ENABLE([https],

debian/control

@@ -2,7 +2,7 @@ Source: httrack
 Section: web
 Maintainer: Xavier Roche <roche@httrack.com>
 Standards-Version: 4.7.4
-Build-Depends: debhelper-compat (= 14), autoconf, autoconf-archive, automake, libtool, zlib1g-dev, libssl-dev
+Build-Depends: debhelper-compat (= 14), autoconf, autoconf-archive, automake, libtool, zlib1g-dev, libssl-dev, libbrotli-dev, libzstd-dev
 Rules-Requires-Root: no
 Homepage: http://www.httrack.com
 Vcs-Git: https://github.com/xroche/httrack.git

m4/check_codecs.m4

@@ -0,0 +1,66 @@
+dnl @synopsis CHECK_BROTLI()
+dnl @synopsis CHECK_ZSTD()
+dnl
+dnl Look for libbrotlidec and libzstd, the decoders for the "br" and "zstd"
+dnl HTTP content codings. Both are optional: a missing library only drops the
+dnl coding from Accept-Encoding. --with-brotli=DIR / --with-zstd=DIR point at a
+dnl prefix; --without-brotli / --without-zstd disable the coding; the default
+dnl is to use the library when it is found.
+dnl
+dnl Define HTS_USEBROTLI / HTS_USEZSTD to 1 or 0, and substitute BROTLI_LIBS /
+dnl ZSTD_LIBS.
+
+dnl CHECK_CODEC(name, NAME, header, library, symbol, companion-libs)
+AC_DEFUN([CHECK_CODEC], [
+AC_ARG_WITH([$1],
+	[AS_HELP_STRING([--with-$1@<:@=DIR@:>@],[Enable the $1 content coding @<:@default=auto@:>@])],
+	[codec_want=$withval], [codec_want=auto])
+$2_LIBS=""
+codec_have=no
+if test "$codec_want" != "no"; then
+	codec_old_cppflags="$CPPFLAGS"
+	codec_old_ldflags="$LDFLAGS"
+	codec_dir=no
+	if test "$codec_want" != "yes" -a "$codec_want" != "auto"; then
+		codec_dir=yes
+		# An explicit prefix is authoritative: if the header is not under
+		# it, error rather than silently pick a system copy.
+		if test ! -f "$codec_want/include/$3"; then
+			AC_MSG_ERROR([$1 requested at $codec_want but $codec_want/include/$3 is missing])
+		fi
+		CPPFLAGS="$CPPFLAGS -I$codec_want/include"
+		LDFLAGS="$LDFLAGS -L$codec_want/lib"
+	fi
+	AC_CHECK_HEADER([$3], [codec_h=yes], [codec_h=no])
+	AC_CHECK_LIB([$4], [$5], [codec_lib=yes], [codec_lib=no], [$6])
+	CPPFLAGS="$codec_old_cppflags"
+	LDFLAGS="$codec_old_ldflags"
+	if test "$codec_h" = "yes" -a "$codec_lib" = "yes"; then
+		codec_have=yes
+		$2_LIBS="-l$4 $6"
+		if test "$codec_dir" = "yes"; then
+			$2_LIBS="-L$codec_want/lib -l$4 $6"
+			# The rest of configure still needs the header path.
+			CPPFLAGS="$CPPFLAGS -I$codec_want/include"
+		fi
+	elif test "$codec_want" != "auto"; then
+		AC_MSG_ERROR([$1 requested but lib$4/$3 not found])
+	fi
+fi
+AC_MSG_CHECKING([whether to enable the $1 content coding])
+AC_MSG_RESULT([$codec_have])
+if test "$codec_have" = "yes"; then
+	AC_DEFINE([HTS_USE$2], [1], [Define to 1 to decode the $1 content coding])
+else
+	AC_DEFINE([HTS_USE$2], [0], [Define to 1 to decode the $1 content coding])
+fi
+AC_SUBST([$2_LIBS])
+AC_SUBST([$2_ENABLED], [$codec_have])
+])
+
+dnl brotlidec needs brotlicommon (the static dictionary) for a fully-static link.
+AC_DEFUN([CHECK_BROTLI],
+	[CHECK_CODEC([brotli], [BROTLI], [brotli/decode.h], [brotlidec], [BrotliDecoderDecompressStream], [-lbrotlicommon])])
+
+AC_DEFUN([CHECK_ZSTD],
+	[CHECK_CODEC([zstd], [ZSTD], [zstd.h], [zstd], [ZSTD_decompressStream], [])])

man/httrack.1

@@ -3,7 +3,7 @@
 .\"
 .\" This file is generated by man/makeman.sh; do not edit by hand.
 .\" SPDX-License-Identifier: GPL-3.0-or-later
-.TH httrack 1 "12 July 2026" "httrack website copier"
+.TH httrack 1 "14 July 2026" "httrack website copier"
 .SH NAME
 httrack \- offline browser : copy websites to a local directory
 .SH SYNOPSIS
@@ -135,7 +135,7 @@ continue an interrupted mirror using the cache (\-\-continue)
 mirror ALL links located in the first level pages (mirror links) (\-\-mirrorlinks)
 .SS Proxy options:
 .IP \-P
-proxy use (\-P proxy:port or \-P user:pass@proxy:port) (\-\-proxy <param>)
+proxy use (\-P [socks5://][user:pass@]proxy:port) (\-\-proxy <param>)
 .IP \-%f
 *use proxy for ftp (f0 don't use) (\-\-httpproxy\-ftp[=N])
 .IP \-%b

src/Makefile.am

@@ -61,7 +61,7 @@ libhttrack_la_SOURCES =  htscore.c htsparse.c htsback.c htscache.c \
 	htshelp.c htslib.c htscoremain.c \
 	htsname.c htsrobots.c htstools.c htswizard.c \
 	htsalias.c htsthread.c htsindex.c htsbauth.c \
-	htsmd5.c htszlib.c htswrap.c htsconcat.c \
+	htsmd5.c htscodec.c htsproxy.c htszlib.c htswrap.c htsconcat.c \
 	htsmodules.c htscharset.c punycode.c htsencoding.c htssniff.c \
 	md5.c \
 	minizip/ioapi.c minizip/mztools.c minizip/unzip.c minizip/zip.c \
@@ -72,17 +72,20 @@ libhttrack_la_SOURCES =  htscore.c htsparse.c htsback.c htscache.c \
 	htshelp.h htsindex.h htslib.h htsmd5.h \
 	htsmodules.h htsname.h htsnet.h htssniff.h \
 	htsopt.h htsrobots.h htsthread.h  \
-	htstools.h htswizard.h htswrap.h htszlib.h  \
+	htstools.h htswizard.h htswrap.h htscodec.h htsproxy.h htszlib.h  \
 	htsstrings.h htsarrays.h httrack-library.h \
 	htscharset.h punycode.h htsencoding.h \
 	htsentities.h htsentities.sh htsbasiccharsets.sh htscodepages.h \
 	md5.h coucal/murmurhash3.h \
 	minizip/crypt.h minizip/ioapi.h minizip/mztools.h minizip/unzip.h minizip/zip.h
-libhttrack_la_LIBADD = $(THREADS_LIBS) $(ZLIB_LIBS) $(OPENSSL_LIBS) $(DL_LIBS) $(SOCKET_LIBS) $(ICONV_LIBS)
+libhttrack_la_LIBADD = $(THREADS_LIBS) $(ZLIB_LIBS) $(BROTLI_LIBS) $(ZSTD_LIBS) $(OPENSSL_LIBS) $(DL_LIBS) $(SOCKET_LIBS) $(ICONV_LIBS)
 libhttrack_la_CFLAGS = $(AM_CFLAGS) -DLIBHTTRACK_EXPORTS -DZLIB_CONST
 libhttrack_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(VERSION_INFO)
 
 EXTRA_DIST = httrack.h webhttrack \
+		version.rc \
+		libhttrack.rc \
+		httrack.rc \
 		coucal/murmurhash3.h.diff \
 		coucal/murmurhash3.h.orig \
 		minizip/iowin32.c \

src/htsback.c

@@ -44,6 +44,8 @@ Please visit our Website: http://www.httrack.com
 #include "htsback.h"
 
 #include "htsftp.h"
+#include "htscodec.h"
+#include "htsproxy.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
 #else
@@ -556,6 +558,14 @@ static int create_back_tmpfile(httrackp *opt, lien_back *const back,
   return 0;
 }
 
+/* Move src onto dst; RENAME does not clobber an existing target on Windows. */
+static hts_boolean replace_file(const char *src, const char *dst) {
+  if (RENAME(src, dst) == 0)
+    return HTS_TRUE;
+  (void) UNLINK(dst);
+  return RENAME(src, dst) == 0 ? HTS_TRUE : HTS_FALSE;
+}
+
 /* Commit or restore a re-fetch backup (#77 follow-up): a re-fetch over an
    existing file moved the good copy to back->tmpfile before truncating url_sav.
    commit keeps the new file and drops the backup; else restore it so an aborted
@@ -571,10 +581,9 @@ static void back_finalize_backup(httrackp *opt, lien_back *const back,
       fclose(back->r.out);
       back->r.out = NULL;
     }
-    (void) UNLINK(back->url_sav); /* drop the failed partial */
-    /* On rename failure keep the backup: it still holds the good copy, so
-       losing it would be worse than an orphaned temp. */
-    if (RENAME(back->tmpfile, back->url_sav) != 0)
+    /* On failure keep the backup: an orphaned temp beats losing the good copy.
+     */
+    if (!replace_file(back->tmpfile, back->url_sav))
       hts_log_print(opt, LOG_WARNING | LOG_ERRNO,
                     "could not restore %s; previous copy kept as %s",
                     back->url_sav, back->tmpfile);
@@ -627,8 +636,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
       if (!back[p].testmode) {  // not test mode
         const char *state = "unknown";
 
-        /* décompression */
-#if HTS_USEZLIB
+        /* Undo the content coding */
         if (back[p].r.compressed) {
           if (back[p].r.size > 0) {
             // stats
@@ -674,28 +682,67 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
             // décompression
             if (back[p].tmpfile != NULL) {
               if (back[p].url_sav[0]) {
+                const hts_codec codec =
+                    hts_codec_parse(back[p].r.contentencoding);
+                /* Never decode over url_sav: a failed decode would destroy the
+                   copy an --update re-fetch is supposed to refresh (#557). */
+                char BIGSTK unpacked[HTS_URLMAXSIZE * 2 + 4]; // room for ".u"
                 LLint size;
 
-                file_notify(opt, back[p].url_adr, back[p].url_fil,
-                            back[p].url_sav, 1, 1, back[p].r.notmodified);
-                filecreateempty(&opt->state.strc, back[p].url_sav);     // filenote & co
-                if ((size = hts_zunpack(back[p].tmpfile, back[p].url_sav)) >= 0) {
+                snprintf(unpacked, sizeof(unpacked), "%s.u", back[p].url_sav);
+                if ((size = hts_codec_unpack(codec, back[p].tmpfile,
+                                             unpacked)) >= 0) {
                   back[p].r.size = back[p].r.totalsize = size;
-                  // fichier -> mémoire
                   if (!back[p].r.is_write) {
+                    // fichier -> mémoire ; le fichier est écrit plus tard
                     deleteaddr(&back[p].r);
-                    back[p].r.adr = readfile_utf8(back[p].url_sav);
+                    back[p].r.adr = readfile_utf8(unpacked);
                     if (!back[p].r.adr) {
                       back[p].r.statuscode = STATUSCODE_INVALID;
                       strcpybuff(back[p].r.msg,
                                  "Read error when decompressing");
                     }
-                    UNLINK(back[p].url_sav);
+                    UNLINK(unpacked);
+                  } else if (replace_file(unpacked, back[p].url_sav)) {
+                    /* The temp bypassed filecreate(), which is what chmods. */
+#ifndef _WIN32
+                    chmod(back[p].url_sav, HTS_ACCESS_FILE);
+#endif
+                    file_notify(opt, back[p].url_adr, back[p].url_fil,
+                                back[p].url_sav, 1, 1, back[p].r.notmodified);
+                    filenote(&opt->state.strc, back[p].url_sav, NULL);
+                  } else {
+                    back[p].r.statuscode = STATUSCODE_INVALID;
+                    strcpybuff(back[p].r.msg,
+                               "Write error when decompressing (can not rename "
+                               "the temporary file)");
+                    /* Keep the decoded body: the failed replace may have
+                       removed the previous copy, leaving this as the only one.
+                     */
+                    hts_log_print(
+                        opt, LOG_WARNING | LOG_ERRNO,
+                        "could not replace %s; decoded copy kept as %s",
+                        back[p].url_sav, unpacked);
                   }
                 } else {
                   back[p].r.statuscode = STATUSCODE_INVALID;
-                  strcpybuff(back[p].r.msg, "Error when decompressing");
+                  snprintf(back[p].r.msg, sizeof(back[p].r.msg),
+                           codec == HTS_CODEC_UNSUPPORTED
+                               ? "Unsupported Content-Encoding (%s)"
+                               : "Error when decompressing (%s)",
+                           back[p].r.contentencoding);
+                  /* Drop the undecoded body so the writer can't commit the
+                     coded bytes as the page; url_sav is left untouched. */
+                  if (!back[p].r.is_write)
+                    deleteaddr(&back[p].r);
+                  UNLINK(unpacked);
                 }
+                /* A failed decode keeps the previously-mirrored copy: note it,
+                   or the update purge (in old.lst, absent from new.lst) would
+                   delete what we just took care not to overwrite. */
+                if (back[p].r.statuscode == STATUSCODE_INVALID &&
+                    fexist_utf8(back[p].url_sav))
+                  filenote(&opt->state.strc, back[p].url_sav, NULL);
               }
               /* ensure that no remaining temporary file exists */
               unlink(back[p].tmpfile);
@@ -708,7 +755,6 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
             // unflag
           }
         }
-#endif
         /* Body fully received: keep the freshly written url_sav, drop the
            backup of the previous copy. */
         back_finalize_backup(opt, &back[p], HTS_TRUE);
@@ -807,7 +853,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
           else
             strcatbuff(flags, "-");
           if (back[p].r.compressed)
-            strcatbuff(flags, "Z");     // gzip
+            strcatbuff(flags, "Z"); // content coding
           else
             strcatbuff(flags, "-");
           /* Err I had to split these.. */
@@ -816,9 +862,7 @@ int back_finalize(httrackp * opt, cache_back * cache, struct_back * sback,
           fprintf(cache->txt, LLintP, (LLint) back[p].r.totalsize);
           fprintf(cache->txt, "\t%s\t", flags);
         }
-#if HTS_USEZLIB
         back[p].r.compressed = 0;
-#endif
 
         if (back[p].r.statuscode == HTTP_OK) {
           if (back[p].r.size >= 0) {
@@ -2068,6 +2112,17 @@ int back_add(struct_back * sback, httrackp * opt, cache_back * cache, const char
                         "error: forbidden test with ftp link for back_add");
           return -1;            // erreur pas de test permis
         }
+        // the ftp client dials the origin itself: over socks that would bypass
+        // the proxy, so fail the link rather than leak the connection (#563)
+        if (back[p].r.req.proxy.active &&
+            hts_proxy_is_socks(back[p].r.req.proxy.name)) {
+          back[p].r.statuscode = STATUSCODE_NON_FATAL;
+          strcpybuff(back[p].r.msg,
+                     "ftp:// is not supported over a SOCKS proxy");
+          back[p].status = STATUS_READY;
+          back_set_finished(sback, p);
+          return 0;
+        }
         if (!(back[p].r.req.proxy.active && opt->ftp_proxy)) {  // connexion directe, gérée en thread
           FTPDownloadStruct *str =
             (FTPDownloadStruct *) malloc(sizeof(FTPDownloadStruct));
@@ -2670,13 +2725,40 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
           }
           busy_state = 1;
 
+          // socks5: tunnel to the origin before anything is written, for http
+          // as well as https. Skip on a reused keep-alive socket (already
+          // tunneled) and on the post-TLS re-entry (ssl_con set) (#563).
+          if (back[i].r.req.proxy.active &&
+              hts_proxy_is_socks(back[i].r.req.proxy.name) &&
+              !back[i].r.keep_alive
+#if HTS_USEOPENSSL
+              && back[i].r.ssl_con == NULL
+#endif
+          ) {
+            const int timeout = back[i].timeout > 0 ? back[i].timeout : 30;
+
+            if (!socks5_handshake(opt, &back[i].r, back[i].url_adr, timeout)) {
+              if (!strnotempty(back[i].r.msg))
+                strcpybuff(back[i].r.msg, "SOCKS5 handshake failed");
+              deletehttp(&back[i].r);
+              back[i].r.soc = INVALID_SOCKET;
+              back[i].r.statuscode = STATUSCODE_NON_FATAL;
+              back[i].status = STATUS_READY;
+              back_set_finished(sback, i);
+              continue;
+            }
+          }
+
 #if HTS_USEOPENSSL
           /* SSL mode */
           if (back[i].r.ssl) {
             int tunnel_ok = 1;
 
-            // https via proxy: CONNECT-tunnel before TLS (#85)
-            if (back[i].r.req.proxy.active && back[i].r.ssl_con == NULL) {
+            // https via an http proxy: CONNECT-tunnel before TLS (#85); socks
+            // already carries the origin connection
+            if (back[i].r.req.proxy.active &&
+                !hts_proxy_is_socks(back[i].r.req.proxy.name) &&
+                back[i].r.ssl_con == NULL) {
               const int timeout = back[i].timeout > 0 ? back[i].timeout : 30;
 
               tunnel_ok =
@@ -2941,11 +3023,13 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                             int last_errno = 0;
 
                             back[i].r.is_write = 1;     // écrire
+                            /* a .gz/.br/.zst saved under its own coding stays
+                               packed on disk */
                             if (back[i].r.compressed &&
-                                /* .gz are *NOT* depacked!! */
-                                strfield(get_ext(catbuff, sizeof(catbuff), back[i].url_sav), "gz") == 0
-                                && strfield(get_ext(catbuff, sizeof(catbuff), back[i].url_sav), "tgz") == 0
-                              ) {
+                                !hts_codec_is_archive_ext(
+                                    hts_codec_parse(back[i].r.contentencoding),
+                                    get_ext(catbuff, sizeof(catbuff),
+                                            back[i].url_sav))) {
                               if (create_back_tmpfile(opt, &back[i], "z") ==
                                   0) {
                                 assertf(back[i].tmpfile != NULL);

src/htscache_selftest.c

@@ -232,11 +232,10 @@ static int disk_fallback_selftest(httrackp *opt) {
   static const char body[] = "BINARY-on-disk-body-0123456789-no-trailing-nul";
   const size_t body_len = sizeof(body) - 1;
 
-  /* X-Save must start with path_html_utf8 so the reader resolves it verbatim
-     (otherwise it re-roots it as a pre-3.40 relative path); then the body we
-     create at fconv(save) is exactly where cache_readex looks for it. */
-  fconcat(save, sizeof(save), StringBuff(opt->path_html_utf8),
-          "example.com/blob.bin");
+  /* a DOS-ified X-Save loses the path_html_utf8 prefix the reader matches on,
+     and gets re-rooted as a pre-3.40 relative path; fconv() only on access */
+  concat(save, sizeof(save), StringBuff(opt->path_html_utf8),
+         "example.com/blob.bin");
 
   /* write only the header (X-In-Cache: 0); the body stays on disk */
   selftest_open_for_write(&cache, opt);
@@ -1253,8 +1252,9 @@ static void corrupt_build_disk(httrackp *opt) {
   memset(corrupt_body_a, 'a', sizeof(corrupt_body_a) - 1);
   remove(reconcile_st_path(opt, "hts-cache/new.zip"));
   remove(reconcile_st_path(opt, "hts-cache/old.zip"));
-  fconcat(save, sizeof(save), StringBuff(opt->path_html_utf8),
-          CORRUPT_ADR "/victim.bin");
+  /* X-Save stored verbatim: see disk_fallback_selftest */
+  concat(save, sizeof(save), StringBuff(opt->path_html_utf8),
+         CORRUPT_ADR "/victim.bin");
   selftest_open_for_write(&cache, opt);
   store_entry(opt, &cache, CORRUPT_ADR, "/canary.html", "canary.html", 200,
               "OK", "text/html", "utf-8", "", "", "", "", corrupt_body_a,

src/htscodec.c

@@ -0,0 +1,366 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: HTTP content codings (gzip/deflate, brotli, zstd)      */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+/* Internal engine bytecode */
+#define HTS_INTERNAL_BYTECODE
+
+#include "htsbase.h"
+#include "htscore.h"
+#include "htscodec.h"
+#include "htszlib.h"
+
+#if HTS_USEBROTLI
+#include <brotli/decode.h>
+#endif
+
+#if HTS_USEZSTD
+#include <zstd.h>
+/* 8 MB, the window an HTTP zstd decoder must honor (RFC 9659); libzstd
+   defaults to 128 MB. */
+#define HTS_ZSTD_WINDOWLOG_MAX 23
+#endif
+
+/* Decoded-size budget, bounding a bomb: brotli and zstd reach a million to one.
+   Deflate cannot pass 1032x, so it only meets this at the 2 GiB ceiling. */
+#define HTS_CODEC_MAX_RATIO 4096
+#define HTS_CODEC_MIN_MAXOUT (1024 * 1024)
+
+LLint hts_codec_maxout(LLint in_size) {
+  LLint maxout;
+
+  if (in_size <= 0 || in_size > INT_MAX / HTS_CODEC_MAX_RATIO)
+    maxout = INT_MAX;
+  else
+    maxout = in_size * HTS_CODEC_MAX_RATIO;
+  if (maxout < HTS_CODEC_MIN_MAXOUT)
+    maxout = HTS_CODEC_MIN_MAXOUT;
+  return maxout;
+}
+
+hts_codec hts_codec_parse(const char *encoding) {
+  if (encoding == NULL || encoding[0] == '\0' ||
+      strfield2(encoding, "identity"))
+    return HTS_CODEC_IDENTITY;
+  if (strfield2(encoding, "gzip") || strfield2(encoding, "x-gzip") ||
+      strfield2(encoding, "deflate") || strfield2(encoding, "x-deflate"))
+    return HTS_USEZLIB ? HTS_CODEC_DEFLATE : HTS_CODEC_UNSUPPORTED;
+  if (strfield2(encoding, "br"))
+    return HTS_USEBROTLI ? HTS_CODEC_BROTLI : HTS_CODEC_UNSUPPORTED;
+  if (strfield2(encoding, "zstd"))
+    return HTS_USEZSTD ? HTS_CODEC_ZSTD : HTS_CODEC_UNSUPPORTED;
+  if (strfield2(encoding, "compress") || strfield2(encoding, "x-compress"))
+    return HTS_CODEC_UNSUPPORTED; /* LZW: never advertised, no decoder here */
+  /* Not a coding at all: broken servers put charsets and the like here, and
+     the plain body they sent must survive it. */
+  return HTS_CODEC_IDENTITY;
+}
+
+#if HTS_USEBROTLI
+#define HTS_AE_BROTLI ", br"
+#else
+#define HTS_AE_BROTLI ""
+#endif
+#if HTS_USEZSTD
+#define HTS_AE_ZSTD ", zstd"
+#else
+#define HTS_AE_ZSTD ""
+#endif
+
+const char *hts_acceptencoding(hts_boolean compressible, hts_boolean secure) {
+  if (!compressible)
+    return "identity";
+#if HTS_USEZLIB
+  /* br and zstd over TLS only, as browsers do: a cleartext intermediary that
+     rewrites a coding it can not read would corrupt the mirror. */
+  if (secure)
+    return "gzip, deflate" HTS_AE_BROTLI HTS_AE_ZSTD ", identity;q=0.9";
+  return "gzip, deflate, identity;q=0.9";
+#else
+  (void) secure;
+  return "identity";
+#endif
+}
+
+hts_boolean hts_codec_is_archive_ext(hts_codec codec, const char *ext) {
+  if (ext == NULL || ext[0] == '\0')
+    return HTS_FALSE;
+  switch (codec) {
+  case HTS_CODEC_DEFLATE:
+    return strfield2(ext, "gz") || strfield2(ext, "tgz") ? HTS_TRUE : HTS_FALSE;
+  case HTS_CODEC_BROTLI:
+    return strfield2(ext, "br") ? HTS_TRUE : HTS_FALSE;
+  case HTS_CODEC_ZSTD:
+    return strfield2(ext, "zst") || strfield2(ext, "tzst") ? HTS_TRUE
+                                                           : HTS_FALSE;
+  default:
+    return HTS_FALSE;
+  }
+}
+
+#if HTS_USEBROTLI || HTS_USEZSTD
+/* Append produced bytes to out under the decoded-size budget, advancing *total.
+   HTS_FALSE on a short write or once the budget is exceeded (a bomb); the
+   over-budget bytes are never written. */
+static hts_boolean codec_sink(FILE *out, const void *buf, size_t produced,
+                              LLint *total, LLint maxout) {
+  if (produced == 0)
+    return HTS_TRUE;
+  *total += (LLint) produced;
+  if (*total > maxout)
+    return HTS_FALSE;
+  return fwrite(buf, 1, produced, out) == produced ? HTS_TRUE : HTS_FALSE;
+}
+#endif
+
+#if HTS_USEBROTLI
+static int codec_unpack_brotli(FILE *in, FILE *out, LLint maxout) {
+  BrotliDecoderState *const state =
+      BrotliDecoderCreateInstance(NULL, NULL, NULL);
+  hts_boolean ok = HTS_TRUE, done = HTS_FALSE;
+  LLint total = 0;
+
+  if (state == NULL)
+    return -1;
+  while (ok && !done) {
+    unsigned char BIGSTK inbuf[8192];
+    size_t avail_in = fread(inbuf, 1, sizeof(inbuf), in);
+    const uint8_t *next_in = inbuf;
+
+    if (avail_in == 0)
+      break; /* EOF; a stream still hungry for input is truncated */
+    for (;;) {
+      unsigned char BIGSTK outbuf[8192];
+      uint8_t *next_out = outbuf;
+      size_t avail_out = sizeof(outbuf);
+      size_t produced;
+      BrotliDecoderResult res;
+
+      res = BrotliDecoderDecompressStream(state, &avail_in, &next_in,
+                                          &avail_out, &next_out, NULL);
+      produced = sizeof(outbuf) - avail_out;
+      if (!codec_sink(out, outbuf, produced, &total, maxout)) {
+        ok = HTS_FALSE;
+        break;
+      }
+      if (res == BROTLI_DECODER_RESULT_ERROR) {
+        ok = HTS_FALSE;
+        break;
+      }
+      if (res == BROTLI_DECODER_RESULT_SUCCESS) {
+        done = HTS_TRUE;
+        break;
+      }
+      if (res == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT)
+        break;
+    }
+    if (ferror(in))
+      ok = HTS_FALSE;
+  }
+  BrotliDecoderDestroyInstance(state);
+  return (ok && done && !ferror(in)) ? (int) total : -1;
+}
+
+static size_t codec_head_brotli(const void *in, size_t in_len, void *out,
+                                size_t out_len) {
+  BrotliDecoderState *const state =
+      BrotliDecoderCreateInstance(NULL, NULL, NULL);
+  const uint8_t *next_in = (const uint8_t *) in;
+  uint8_t *next_out = (uint8_t *) out;
+  size_t avail_in = in_len, avail_out = out_len;
+  BrotliDecoderResult res;
+
+  if (state == NULL)
+    return 0;
+  res = BrotliDecoderDecompressStream(state, &avail_in, &next_in, &avail_out,
+                                      &next_out, NULL);
+  BrotliDecoderDestroyInstance(state);
+  return (res != BROTLI_DECODER_RESULT_ERROR) ? out_len - avail_out : 0;
+}
+#endif
+
+#if HTS_USEZSTD
+static int codec_unpack_zstd(FILE *in, FILE *out, LLint maxout) {
+  ZSTD_DStream *const zds = ZSTD_createDStream();
+  hts_boolean ok = HTS_TRUE, eof = HTS_FALSE;
+  size_t zret = 1; /* 0 once a frame is fully flushed */
+  LLint total = 0;
+
+  if (zds == NULL)
+    return -1;
+  if (ZSTD_isError(ZSTD_DCtx_setParameter(zds, ZSTD_d_windowLogMax,
+                                          HTS_ZSTD_WINDOWLOG_MAX))) {
+    ZSTD_freeDStream(zds);
+    return -1;
+  }
+  while (ok && !eof) {
+    unsigned char BIGSTK inbuf[8192];
+    ZSTD_inBuffer input;
+
+    input.src = inbuf;
+    input.size = fread(inbuf, 1, sizeof(inbuf), in);
+    input.pos = 0;
+    if (input.size == 0) {
+      eof = HTS_TRUE;
+      break;
+    }
+    while (input.pos < input.size) {
+      unsigned char BIGSTK outbuf[8192];
+      ZSTD_outBuffer output;
+
+      output.dst = outbuf;
+      output.size = sizeof(outbuf);
+      output.pos = 0;
+      zret = ZSTD_decompressStream(zds, &output, &input);
+      if (ZSTD_isError(zret)) {
+        ok = HTS_FALSE;
+        break;
+      }
+      if (!codec_sink(out, outbuf, output.pos, &total, maxout)) {
+        ok = HTS_FALSE;
+        break;
+      }
+    }
+    if (ferror(in))
+      ok = HTS_FALSE;
+  }
+  ZSTD_freeDStream(zds);
+  /* zret != 0 at EOF: the last frame never completed */
+  return (ok && zret == 0 && !ferror(in)) ? (int) total : -1;
+}
+
+static size_t codec_head_zstd(const void *in, size_t in_len, void *out,
+                              size_t out_len) {
+  ZSTD_DStream *const zds = ZSTD_createDStream();
+  ZSTD_inBuffer input;
+  ZSTD_outBuffer output;
+  size_t zret;
+
+  if (zds == NULL)
+    return 0;
+  if (ZSTD_isError(ZSTD_DCtx_setParameter(zds, ZSTD_d_windowLogMax,
+                                          HTS_ZSTD_WINDOWLOG_MAX))) {
+    ZSTD_freeDStream(zds);
+    return 0;
+  }
+  input.src = in;
+  input.size = in_len;
+  input.pos = 0;
+  output.dst = out;
+  output.size = out_len;
+  output.pos = 0;
+  zret = ZSTD_decompressStream(zds, &output, &input);
+  ZSTD_freeDStream(zds);
+  return ZSTD_isError(zret) ? 0 : output.pos;
+}
+#endif
+
+LLint hts_codec_coded_size(FILE *in) {
+  long size;
+
+  if (fseek(in, 0, SEEK_END) != 0)
+    return -1;
+  size = ftell(in);
+  if (size < 0 || fseek(in, 0, SEEK_SET) != 0)
+    return -1;
+  return (LLint) size;
+}
+
+int hts_codec_unpack(hts_codec codec, const char *filename,
+                     const char *newfile) {
+  if (filename == NULL || newfile == NULL || !filename[0] || !newfile[0])
+    return -1;
+  switch (codec) {
+  case HTS_CODEC_DEFLATE:
+#if HTS_USEZLIB
+    return hts_zunpack(filename, newfile);
+#else
+    return -1;
+#endif
+  case HTS_CODEC_BROTLI:
+  case HTS_CODEC_ZSTD:
+    break;
+  default: /* IDENTITY never reaches the unpacker; UNSUPPORTED must fail */
+    return -1;
+  }
+#if HTS_USEBROTLI || HTS_USEZSTD
+  {
+    char catbuff[CATBUFF_SIZE];
+    FILE *out, *in = FOPEN(fconv(catbuff, sizeof(catbuff), filename), "rb");
+    LLint maxout;
+    int ret = -1;
+
+    if (in == NULL)
+      return -1;
+    maxout = hts_codec_maxout(hts_codec_coded_size(in));
+    out = FOPEN(fconv(catbuff, sizeof(catbuff), newfile), "wb");
+    if (out == NULL) {
+      fclose(in);
+      return -1;
+    }
+#if HTS_USEBROTLI
+    if (codec == HTS_CODEC_BROTLI)
+      ret = codec_unpack_brotli(in, out, maxout);
+#endif
+#if HTS_USEZSTD
+    if (codec == HTS_CODEC_ZSTD)
+      ret = codec_unpack_zstd(in, out, maxout);
+#endif
+    fclose(out);
+    fclose(in);
+    return ret;
+  }
+#else
+  return -1;
+#endif
+}
+
+size_t hts_codec_head(hts_codec codec, const void *in, size_t in_len, void *out,
+                      size_t out_len) {
+  if (in == NULL || in_len == 0 || out == NULL || out_len == 0)
+    return 0;
+  switch (codec) {
+#if HTS_USEZLIB
+  case HTS_CODEC_DEFLATE:
+    return hts_zhead(in, in_len, out, out_len);
+#endif
+#if HTS_USEBROTLI
+  case HTS_CODEC_BROTLI:
+    return codec_head_brotli(in, in_len, out, out_len);
+#endif
+#if HTS_USEZSTD
+  case HTS_CODEC_ZSTD:
+    return codec_head_zstd(in, in_len, out, out_len);
+#endif
+  default:
+    return 0;
+  }
+}

src/htscodec.h

@@ -0,0 +1,79 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: HTTP content codings (gzip/deflate, brotli, zstd)      */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+#ifndef HTS_DEFCODEC
+#define HTS_DEFCODEC
+
+#include "htsglobal.h"
+
+/* Content codings we may meet in a Content-Encoding header. */
+typedef enum {
+  HTS_CODEC_IDENTITY = 0, /**< no coding, or a token we treat as none */
+  HTS_CODEC_DEFLATE,      /**< gzip, x-gzip, deflate, x-deflate */
+  HTS_CODEC_BROTLI,       /**< br */
+  HTS_CODEC_ZSTD,         /**< zstd */
+  HTS_CODEC_UNSUPPORTED   /**< a real coding we can not decode */
+} hts_codec;
+
+#ifdef HTS_INTERNAL_BYTECODE
+
+/* Codec for a Content-Encoding token. A known coding we can not decode is
+   UNSUPPORTED; an unrecognized token is IDENTITY (servers do emit junk). */
+extern hts_codec hts_codec_parse(const char *encoding);
+
+/* Accept-Encoding value to advertise; secure (TLS) also offers br and zstd. */
+extern const char *hts_acceptencoding(hts_boolean compressible,
+                                      hts_boolean secure);
+
+/* HTS_TRUE if ext is the codec's own archive extension: a foo.gz served as
+   Content-Encoding: gzip stays packed on disk. */
+extern hts_boolean hts_codec_is_archive_ext(hts_codec codec, const char *ext);
+
+/* Decode filename into newfile. Returns the decoded size, or -1 on a truncated
+   or corrupt stream, an unsupported coding, a bomb over the budget, or I/O. */
+extern int hts_codec_unpack(hts_codec codec, const char *filename,
+                            const char *newfile);
+
+/* Decode up to out_len leading bytes of a coded body for the MIME sniffer;
+   0 when nothing could be decoded. */
+extern size_t hts_codec_head(hts_codec codec, const void *in, size_t in_len,
+                             void *out, size_t out_len);
+
+/* Ceiling on the decoded size of a body of in_size coded bytes. */
+extern LLint hts_codec_maxout(LLint in_size);
+
+/* Coded size of an open stream, left rewound; -1 if unknown. */
+extern LLint hts_codec_coded_size(FILE *in);
+
+#endif
+
+#endif

src/htscoremain.c

@@ -2253,21 +2253,12 @@ static int hts_main_internal(int argc, char **argv, httrackp * opt) {
               htsmain_free();
               return -1;
             } else {
-              char *a;
+              char BIGSTK pname[HTS_URLMAXSIZE * 2];
 
               na++;
               opt->proxy.active = 1;
-              // Rechercher MAIS en partant de la fin à cause de user:pass@proxy:port
-              a = argv[na] + strlen(argv[na]) - 1;
-              while((a > argv[na]) && (*a != ':') && (*a != '@'))
-                a--;
-              if (*a == ':') {  // un port est présent, <proxy>:port
-                sscanf(a + 1, "%d", &opt->proxy.port);
-                StringCopyN(opt->proxy.name, argv[na], (int) (a - argv[na]));
-              } else {          // <proxy>
-                opt->proxy.port = 8080;
-                StringCopy(opt->proxy.name, argv[na]);
-              }
+              hts_parse_proxy(argv[na], pname, sizeof(pname), &opt->proxy.port);
+              StringCopy(opt->proxy.name, pname);
             }
             break;
           case 'F':            // user-agent field

src/htsglobal.h

@@ -140,6 +140,15 @@ Please visit our Website: http://www.httrack.com
 #define HTS_USEZLIB 1
 #endif
 
+// brotli and zstd content codings; off unless the build opted in (configure,
+// or the Visual Studio projects, which link the vcpkg libraries)
+#ifndef HTS_USEBROTLI
+#define HTS_USEBROTLI 0
+#endif
+#ifndef HTS_USEZSTD
+#define HTS_USEZSTD 0
+#endif
+
 #ifndef HTS_INET6
 #define HTS_INET6 0
 #endif

src/htshelp.c

@@ -477,7 +477,7 @@ void help(const char *app, int more) {
     ("  Y   mirror ALL links located in the first level pages (mirror links)");
   infomsg("");
   infomsg("Proxy options:");
-  infomsg("  P  proxy use (-P proxy:port or -P user:pass@proxy:port)");
+  infomsg("  P  proxy use (-P [socks5://][user:pass@]proxy:port)");
   infomsg(" %f *use proxy for ftp (f0 don't use)");
   infomsg(" %b  use this local hostname to make/send requests (-%b hostname)");
   infomsg("");

src/htslib.c

@@ -48,6 +48,7 @@ Please visit our Website: http://www.httrack.com
 #include "htsmodules.h"
 #include "htscharset.h"
 #include "htsencoding.h"
+#include "htscodec.h"
 
 #ifdef _WIN32
 #include <direct.h>
@@ -648,165 +649,6 @@ T_SOC http_fopen(httrackp * opt, const char *adr, const char *fil, htsblk * reto
   return http_xfopen(opt, 0, 1, 1, NULL, adr, fil, retour);
 }
 
-// Read a CRLF line from a non-blocking socket (waits up to timeout per recv).
-// Returns the line length (0 = empty), or -1 on timeout/EOF/error.
-static int proxy_getline(T_SOC soc, char *s, int max, int timeout) {
-  int j = 0;
-
-  for (;;) {
-    unsigned char ch;
-    int n;
-
-    if (!check_readinput_t(soc, timeout))
-      return -1; // timed out waiting for data
-    n = (int) recv(soc, &ch, 1, 0);
-    if (n == 1) {
-      if (ch == 13) // CR
-        continue;
-      if (ch == 10) // LF: end of line
-        break;
-      if (j >= max - 1)
-        return -1; // line too long: bound the read against a hostile proxy
-      s[j++] = (char) ch;
-    } else if (n == 0) {
-      return -1; // connection closed
-    } else {
-#ifdef _WIN32
-      if (WSAGetLastError() == WSAEWOULDBLOCK)
-        continue;
-#else
-      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
-        continue;
-#endif
-      return -1;
-    }
-  }
-  s[j] = '\0';
-  return j;
-}
-
-int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
-                      int timeout) {
-  const T_SOC soc = retour->soc;
-  const char *const host = jump_identification_const(adr); // host[:port]
-  const char *const portsep = jump_toport_const(adr);      // ":port" or NULL
-  char BIGSTK authority[HTS_URLMAXSIZE * 2];
-  char BIGSTK req[HTS_URLMAXSIZE * 4 + 1100];
-  char line[1024];
-  int code;
-
-  if (soc == INVALID_SOCKET)
-    return 0;
-
-  // CONNECT needs an explicit host:port; default the https port
-  authority[0] = '\0';
-  if (portsep != NULL)
-    strlcatbuff(authority, host, sizeof(authority)); // already host:port
-  else
-    snprintf(authority, sizeof(authority), "%s:%d", host, 443);
-
-  // backstop: never let a stray CR/LF in the host smuggle a second line into
-  // the CONNECT request (the host is already sanitized upstream)
-  {
-    const char *c;
-
-    for (c = authority; *c != '\0'; c++) {
-      if ((unsigned char) *c < ' ') {
-        strcpybuff(retour->msg, "proxy CONNECT: invalid host");
-        return 0;
-      }
-    }
-  }
-
-  snprintf(req, sizeof(req), "CONNECT %s HTTP/1.0" H_CRLF "Host: %s" H_CRLF,
-           authority, authority);
-
-  // creds go on the CONNECT, not the tunneled origin request
-  if (link_has_authorization(retour->req.proxy.name)) {
-    const char *a = jump_identification_const(retour->req.proxy.name);
-    const char *astart = jump_protocol_const(retour->req.proxy.name);
-    char autorisation[1100];
-    char user_pass[256];
-
-    autorisation[0] = user_pass[0] = '\0';
-    strncatbuff(user_pass, astart, (int) (a - astart) - 1);
-    strcpybuff(user_pass, unescape_http(OPT_GET_BUFF(opt),
-                                        OPT_GET_BUFF_SIZE(opt), user_pass));
-    code64((unsigned char *) user_pass, (int) strlen(user_pass),
-           (unsigned char *) autorisation, 0);
-    strlcatbuff(req, "Proxy-Authorization: Basic ", sizeof(req));
-    strlcatbuff(req, autorisation, sizeof(req));
-    strlcatbuff(req, H_CRLF, sizeof(req));
-  }
-  strlcatbuff(req, H_CRLF, sizeof(req)); // end of request headers
-
-  // raw send: ssl is set, so sendc() would route to TLS
-  {
-    const char *p = req;
-    size_t remain = strlen(req);
-    int stalls = 0;
-
-    while (remain > 0) {
-      const int n = (int) send(soc, p, (int) remain, 0);
-
-      if (n > 0) {
-        p += n;
-        remain -= (size_t) n;
-        stalls = 0;
-      } else {
-#ifdef _WIN32
-        const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
-#else
-        const int wouldblock =
-            (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
-#endif
-        // don't spin forever on a fatal error or an unwritable socket
-        if (!wouldblock || !check_writeinput_t(soc, timeout) ||
-            ++stalls > 100) {
-          strcpybuff(retour->msg, "proxy CONNECT: write error");
-          return 0;
-        }
-      }
-    }
-  }
-
-  // proxy status line: "HTTP/1.x <code> ..."
-  if (proxy_getline(soc, line, sizeof(line), timeout) < 0) {
-    strcpybuff(retour->msg, "proxy CONNECT: no response");
-    return 0;
-  }
-  if (sscanf(line, "HTTP/%*d.%*d %d", &code) < 1)
-    code = 0;
-  if (code < 200 || code >= 300) {
-    snprintf(retour->msg, sizeof(retour->msg), "proxy CONNECT refused: %s",
-             strnotempty(line) ? line : "(no status)");
-    return 0;
-  }
-
-  // drain headers to the blank line; cap the count so a flooding proxy can't
-  // stall the crawl
-  {
-    int headers = 0;
-
-    for (;;) {
-      const int n = proxy_getline(soc, line, sizeof(line), timeout);
-
-      if (n < 0) {
-        strcpybuff(retour->msg, "proxy CONNECT: truncated response");
-        return 0;
-      }
-      if (n == 0)
-        break; // blank line: tunnel ready
-      if (++headers > 64) {
-        strcpybuff(retour->msg, "proxy CONNECT: too many response headers");
-        return 0;
-      }
-    }
-  }
-
-  return 1;
-}
-
 // ouverture d'une liaison http, envoi d'une requète
 // mode: 0 GET  1 HEAD  [2 POST]
 // treat: traiter header?
@@ -1105,8 +947,9 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
           /* widths bound method[256], url[HTS_URLMAXSIZE*2], protocol[256] */
           if (sscanf(line, "%255s %2047s %255s", method, url, protocol) == 3) {
             size_t ret;
-            // selon que l'on a ou pas un proxy
-            if (retour->req.proxy.active) {
+            // absolute-URI for an http proxy; a socks tunnel takes origin-form
+            if (retour->req.proxy.active &&
+                !hts_proxy_is_socks(retour->req.proxy.name)) {
               print_buffer(&bstr,
                       "%s http://%s%s %s\r\n", method, adr, url,
                       protocol);
@@ -1142,8 +985,10 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
         print_buffer(&bstr, "HEAD ");
     }
 
-    // si on gère un proxy, il faut une Absolute URI: on ajoute avant http://www.adr.dom
-    if (retour->req.proxy.active && (strncmp(adr, "https://", 8) != 0)) {
+    // an http proxy needs an absolute URI; a socks tunnel does not
+    if (retour->req.proxy.active &&
+        !hts_proxy_is_socks(retour->req.proxy.name) &&
+        (strncmp(adr, "https://", 8) != 0)) {
       if (!link_has_authority(adr)) {   // default http
 #if HDEBUG
         printf("Proxy Use: for %s%s proxy %d port %d\n", adr, fil,
@@ -1187,8 +1032,11 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
     if (xsend)
       print_buffer(&bstr, "%s", xsend);  // éventuelles autres lignes
 
-    // for https, auth rides the CONNECT (the tunneled GET would leak it)
-    if (retour->req.proxy.active && strncmp(adr, "https://", 8) != 0) {
+    // for https, auth rides the CONNECT (the tunneled GET would leak it); for
+    // socks, the handshake
+    if (retour->req.proxy.active &&
+        !hts_proxy_is_socks(retour->req.proxy.name) &&
+        strncmp(adr, "https://", 8) != 0) {
       if (link_has_authorization(retour->req.proxy.name)) {     // et hop, authentification proxy!
         const char *a = jump_identification_const(retour->req.proxy.name);
         const char *astart = jump_protocol_const(retour->req.proxy.name);
@@ -1279,11 +1127,16 @@ int http_sendhead(httrackp * opt, t_cookie * cookie, int mode,
       // Compression accepted ?
       if (retour->req.http11) {
         hts_boolean compressible = HTS_FALSE;
+        hts_boolean secure = HTS_FALSE;
+
 #if HTS_USEZLIB
         compressible = (!retour->req.range_used && !retour->req.nocompression);
+#endif
+#if HTS_USEOPENSSL
+        secure = retour->ssl ? HTS_TRUE : HTS_FALSE;
 #endif
         print_buffer(&bstr, "Accept-Encoding: %s" H_CRLF,
-                     hts_acceptencoding(compressible));
+                     hts_acceptencoding(compressible, secure));
       }
 
       /* Authentification */
@@ -1668,22 +1521,10 @@ void treathead(t_cookie * cookie, const char *adr, const char *fil, htsblk * ret
         strcpybuff(retour->contentencoding, tempo);
       else
         retour->contentencoding[0] = '\0';
-#if HTS_USEZLIB
-      /* Check known encodings */
-      if (retour->contentencoding[0]) {
-        if ((strfield2(retour->contentencoding, "gzip"))
-            || (strfield2(retour->contentencoding, "x-gzip"))
-            /*
-               || (strfield2(retour->contentencoding, "compress"))
-               || (strfield2(retour->contentencoding, "x-compress"))
-             */
-            || (strfield2(retour->contentencoding, "deflate"))
-            || (strfield2(retour->contentencoding, "x-deflate"))
-          ) {
-          retour->compressed = 1;
-        }
-      }
-#endif
+      /* A coding to undo (or one we can not undo, which must fail the fetch
+         rather than save the coded bytes as the page) */
+      if (hts_codec_parse(retour->contentencoding) != HTS_CODEC_IDENTITY)
+        retour->compressed = 1;
     }
   } else if ((p = strfield(rcvd, "Location:")) != 0) {
     if (retour) {
@@ -3872,6 +3713,10 @@ const char *jump_protocol_const(const char *source) {
     source += p;
   else if ((p = strfield(source, "file:")))
     source += p;
+  else if ((p = strfield(source, "socks5h:")))
+    source += p;
+  else if ((p = strfield(source, "socks5:")))
+    source += p;
   // net_path
   if (strncmp(source, "//", 2) == 0)
     source += 2;
@@ -3880,6 +3725,48 @@ const char *jump_protocol_const(const char *source) {
 
 DECLARE_NON_CONST_VERSION(jump_protocol)
 
+hts_boolean hts_proxy_is_socks(const char *name) {
+  if (name == NULL)
+    return HTS_FALSE;
+  return (strfield(name, "socks5h:") || strfield(name, "socks5:")) ? HTS_TRUE
+                                                                   : HTS_FALSE;
+}
+
+// default proxy port for a -P argument, keyed on the scheme
+static int proxy_default_port(const char *arg) {
+  return hts_proxy_is_socks(arg) ? 1080 : 8080;
+}
+
+void hts_parse_proxy(const char *arg, char *name, size_t name_size, int *port) {
+  const char *authority = strstr(arg, "://");
+  const char *a;
+  size_t namelen;
+
+  if (name_size == 0)
+    return;
+  // scan back to the port ':' (or userinfo '@'), but never past the authority,
+  // so a scheme's own colon is not read as a port separator; inspect a[-1] from
+  // one-past-end so no pointer below the string is ever formed
+  authority = (authority != NULL) ? authority + 3 : arg;
+  a = arg + strlen(arg);
+  while (a > authority && a[-1] != ':' && a[-1] != '@')
+    a--;
+  if (a > authority && a[-1] == ':') {
+    int p = -1;
+
+    sscanf(a, "%d", &p);
+    *port = (p > 0) ? p : proxy_default_port(arg);
+    namelen = (size_t) (a - 1 - arg);
+  } else {
+    *port = proxy_default_port(arg);
+    namelen = strlen(arg);
+  }
+  if (namelen >= name_size) // arg is user-controlled: truncate, don't overflow
+    namelen = name_size - 1;
+  memcpy(name, arg, namelen);
+  name[namelen] = '\0';
+}
+
 // codage base 64 a vers b
 void code64(unsigned char *a, int size_a, unsigned char *b, int crlf) {
   int i1 = 0, i2 = 0, i3 = 0, i4 = 0;
@@ -4365,11 +4252,6 @@ HTSEXT_API void get_httptype(httrackp *opt, char *s, const char *fil,
   (void) get_httptype_sized(opt, s, HTS_MIMETYPE_SIZE, fil, flag);
 }
 
-/* Advertised Accept-Encoding; gzip and deflate both decode via hts_zunpack */
-const char *hts_acceptencoding(hts_boolean compressible) {
-  return compressible ? "gzip, deflate, identity;q=0.9" : "identity";
-}
-
 // get type of fil (php)
 // s: buffer (text/html) or NULL
 // return: 1 if known by user

src/htslib.h

@@ -207,15 +207,9 @@ int check_readinput(htsblk * r);
 int check_readinput_t(T_SOC soc, int timeout);
 int check_writeinput_t(T_SOC soc, int timeout);
 
-/* Open an HTTP CONNECT tunnel through the active proxy for an https request:
-   `retour->soc` must already be TCP-connected to the proxy, and `adr` is the
-   origin authority (url_adr, e.g. "https://host:port"). Sends the CONNECT
-   request (with Proxy-Authorization when the proxy carries credentials) and
-   reads the proxy's status line, so the caller's TLS handshake then runs
-   end-to-end with the origin. Blocks up to `timeout` seconds. Returns 1 on a
-   2xx tunnel, 0 on failure (retour->msg/statuscode set). */
-int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
-                      int timeout);
+/* TRUE if this -P proxy name (which keeps its scheme) is a SOCKS5 proxy. */
+hts_boolean hts_proxy_is_socks(const char *name);
+
 void treathead(t_cookie * cookie, const char *adr, const char *fil, htsblk * retour,
                char *rcvd);
 void treatfirstline(htsblk * retour, const char *rcvd);
@@ -283,15 +277,18 @@ int ishttperror(int err);
 int get_userhttptype(httrackp * opt, char *s, const char *fil);
 int give_mimext(char *s, size_t ssize, const char *st);
 
-/* Advertised Accept-Encoding value (no header name/CRLF); see htslib.c. */
-const char *hts_acceptencoding(hts_boolean compressible);
-
 int may_bogus_multiple(httrackp * opt, const char *mime, const char *filename);
 int may_unknown2(httrackp * opt, const char *mime, const char *filename);
 
 const char *strrchr_limit(const char *s, char c, const char *limit);
 char *jump_protocol(char *source);
 const char *jump_protocol_const(const char *source);
+
+/* Split a -P proxy argument "[scheme://][user:pass@]host[:port]" into the proxy
+   host string (scheme and any user:pass kept, for later stripping and auth),
+   written NUL-terminated into name[name_size] (truncated to fit), and the port
+   in *port. The port defaults by scheme: 1080 for socks5/socks5h, else 8080. */
+void hts_parse_proxy(const char *arg, char *name, size_t name_size, int *port);
 void code64(unsigned char *a, int size_a, unsigned char *b, int crlf);
 
 #define copychar(catbuff,a) concat(catbuff,(a),NULL)

src/htsname.c

@@ -42,6 +42,7 @@ Please visit our Website: http://www.httrack.com
 #include "htscharset.h"
 #include "htsencoding.h"
 #include "htssniff.h"
+#include "htscodec.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
 #endif
@@ -151,29 +152,6 @@ typedef struct sniff_src {
   const char *prev_save; /* previous run's save name (cache X-Save) */
 } sniff_src;
 
-#if HTS_USEZLIB
-/* Inflate the head of a gzip/zlib stream; 0 when undecodable. */
-static size_t sniff_inflate_head(const void *in, size_t in_len, void *out,
-                                 size_t out_len) {
-  z_stream zs;
-  size_t n = 0;
-  int err;
-
-  memset(&zs, 0, sizeof(zs));
-  if (inflateInit2(&zs, 47) != Z_OK) /* 47: gzip or zlib, autodetected */
-    return 0;
-  zs.next_in = (const Bytef *) in;
-  zs.avail_in = (uInt) in_len;
-  zs.next_out = (Bytef *) out;
-  zs.avail_out = (uInt) out_len;
-  err = inflate(&zs, Z_SYNC_FLUSH);
-  if (err == Z_OK || err == Z_STREAM_END || err == Z_BUF_ERROR)
-    n = out_len - zs.avail_out;
-  inflateEnd(&zs);
-  return n;
-}
-#endif
-
 static size_t sniff_read_head(const char *path, void *buf, size_t len) {
   char catbuff[CATBUFF_SIZE];
   FILE *const fp = FOPEN(fconv(catbuff, sizeof(catbuff), path), "rb");
@@ -205,16 +183,12 @@ static size_t sniff_slot_head(const lien_back *slot, void *buf, size_t len) {
       n = sniff_read_head(slot->tmpfile, buf, len);
   }
   if (n > 0 && r->compressed) {
-#if HTS_USEZLIB
     unsigned char raw[HTS_SNIFF_LEN];
 
     if (n > sizeof(raw))
       n = sizeof(raw);
     memcpy(raw, buf, n);
-    n = sniff_inflate_head(raw, n, buf, len);
-#else
-    n = 0;
-#endif
+    n = hts_codec_head(hts_codec_parse(r->contentencoding), raw, n, buf, len);
   }
   return n;
 }

src/htsopt.h

@@ -328,8 +328,8 @@ typedef enum hts_wizard {
 
 typedef enum hts_robots {
   HTS_ROBOTS_NEVER = 0,        /**< ignore robots rules */
-  HTS_ROBOTS_SOMETIMES = 1,    /**< partial obedience (default) */
-  HTS_ROBOTS_ALWAYS = 2,       /**< obey robots rules */
+  HTS_ROBOTS_SOMETIMES = 1,    /**< partial obedience, set by -s */
+  HTS_ROBOTS_ALWAYS = 2,       /**< obey robots rules (default) */
   HTS_ROBOTS_ALWAYS_STRICT = 3 /**< obey even strict rules */
 } hts_robots;
 #endif

src/htsproxy.c

@@ -0,0 +1,539 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: Proxy tunneling (HTTP CONNECT, SOCKS5)                 */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+/* Internal engine bytecode */
+#define HTS_INTERNAL_BYTECODE
+
+#include "htscore.h"
+
+#include "htslib.h"
+#include "htsproxy.h"
+
+#include <string.h>
+
+// Read a CRLF line from a non-blocking socket (waits up to timeout per recv).
+// Returns the line length (0 = empty), or -1 on timeout/EOF/error.
+static int proxy_getline(T_SOC soc, char *s, int max, int timeout) {
+  int j = 0;
+
+  for (;;) {
+    unsigned char ch;
+    int n;
+
+    if (!check_readinput_t(soc, timeout))
+      return -1; // timed out waiting for data
+    n = (int) recv(soc, &ch, 1, 0);
+    if (n == 1) {
+      if (ch == 13) // CR
+        continue;
+      if (ch == 10) // LF: end of line
+        break;
+      if (j >= max - 1)
+        return -1; // line too long: bound the read against a hostile proxy
+      s[j++] = (char) ch;
+    } else if (n == 0) {
+      return -1; // connection closed
+    } else {
+#ifdef _WIN32
+      if (WSAGetLastError() == WSAEWOULDBLOCK)
+        continue;
+#else
+      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
+        continue;
+#endif
+      return -1;
+    }
+  }
+  s[j] = '\0';
+  return j;
+}
+
+int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
+                      int timeout) {
+  const T_SOC soc = retour->soc;
+  const char *const host = jump_identification_const(adr); // host[:port]
+  const char *const portsep = jump_toport_const(adr);      // ":port" or NULL
+  char BIGSTK authority[HTS_URLMAXSIZE * 2];
+  char BIGSTK req[HTS_URLMAXSIZE * 4 + 1100];
+  char line[1024];
+  int code;
+
+  if (soc == INVALID_SOCKET)
+    return 0;
+
+  // CONNECT needs an explicit host:port; default the https port
+  authority[0] = '\0';
+  if (portsep != NULL)
+    strlcatbuff(authority, host, sizeof(authority)); // already host:port
+  else
+    snprintf(authority, sizeof(authority), "%s:%d", host, 443);
+
+  // backstop: never let a stray CR/LF in the host smuggle a second line into
+  // the CONNECT request (the host is already sanitized upstream)
+  {
+    const char *c;
+
+    for (c = authority; *c != '\0'; c++) {
+      if ((unsigned char) *c < ' ') {
+        strcpybuff(retour->msg, "proxy CONNECT: invalid host");
+        return 0;
+      }
+    }
+  }
+
+  snprintf(req, sizeof(req), "CONNECT %s HTTP/1.0" H_CRLF "Host: %s" H_CRLF,
+           authority, authority);
+
+  // creds go on the CONNECT, not the tunneled origin request
+  if (link_has_authorization(retour->req.proxy.name)) {
+    const char *a = jump_identification_const(retour->req.proxy.name);
+    const char *astart = jump_protocol_const(retour->req.proxy.name);
+    char autorisation[1100];
+    char user_pass[256];
+
+    autorisation[0] = user_pass[0] = '\0';
+    strncatbuff(user_pass, astart, (int) (a - astart) - 1);
+    strcpybuff(user_pass, unescape_http(OPT_GET_BUFF(opt),
+                                        OPT_GET_BUFF_SIZE(opt), user_pass));
+    code64((unsigned char *) user_pass, (int) strlen(user_pass),
+           (unsigned char *) autorisation, 0);
+    strlcatbuff(req, "Proxy-Authorization: Basic ", sizeof(req));
+    strlcatbuff(req, autorisation, sizeof(req));
+    strlcatbuff(req, H_CRLF, sizeof(req));
+  }
+  strlcatbuff(req, H_CRLF, sizeof(req)); // end of request headers
+
+  // raw send: ssl is set, so sendc() would route to TLS
+  {
+    const char *p = req;
+    size_t remain = strlen(req);
+    int stalls = 0;
+
+    while (remain > 0) {
+      const int n = (int) send(soc, p, (int) remain, 0);
+
+      if (n > 0) {
+        p += n;
+        remain -= (size_t) n;
+        stalls = 0;
+      } else {
+#ifdef _WIN32
+        const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+        const int wouldblock =
+            (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+        // don't spin forever on a fatal error or an unwritable socket
+        if (!wouldblock || !check_writeinput_t(soc, timeout) ||
+            ++stalls > 100) {
+          strcpybuff(retour->msg, "proxy CONNECT: write error");
+          return 0;
+        }
+      }
+    }
+  }
+
+  // proxy status line: "HTTP/1.x <code> ..."
+  if (proxy_getline(soc, line, sizeof(line), timeout) < 0) {
+    strcpybuff(retour->msg, "proxy CONNECT: no response");
+    return 0;
+  }
+  if (sscanf(line, "HTTP/%*d.%*d %d", &code) < 1)
+    code = 0;
+  if (code < 200 || code >= 300) {
+    snprintf(retour->msg, sizeof(retour->msg), "proxy CONNECT refused: %s",
+             strnotempty(line) ? line : "(no status)");
+    return 0;
+  }
+
+  // drain headers to the blank line; cap the count so a flooding proxy can't
+  // stall the crawl
+  {
+    int headers = 0;
+
+    for (;;) {
+      const int n = proxy_getline(soc, line, sizeof(line), timeout);
+
+      if (n < 0) {
+        strcpybuff(retour->msg, "proxy CONNECT: truncated response");
+        return 0;
+      }
+      if (n == 0)
+        break; // blank line: tunnel ready
+      if (++headers > 64) {
+        strcpybuff(retour->msg, "proxy CONNECT: too many response headers");
+        return 0;
+      }
+    }
+  }
+
+  return 1;
+}
+
+/* SOCKS5 client (RFC 1928, RFC 1929 auth), hostname mode only: the proxy
+   resolves the origin name (remote DNS, curl's socks5h). The stream is the
+   proxy socket, or a scripted buffer under -#test=socks5. */
+
+#define SOCKS5_VERSION 0x05
+#define SOCKS5_AUTH_VERSION 0x01
+#define SOCKS5_METHOD_NONE 0x00
+#define SOCKS5_METHOD_USERPASS 0x02
+#define SOCKS5_METHOD_NOACCEPTABLE 0xFF
+#define SOCKS5_CMD_CONNECT 0x01
+#define SOCKS5_ATYP_IPV4 0x01
+#define SOCKS5_ATYP_DOMAIN 0x03
+#define SOCKS5_ATYP_IPV6 0x04
+#define SOCKS5_MAXFIELD 255 /* one length byte: host, user and password */
+
+typedef struct socks5_stream {
+  T_SOC soc; /* INVALID_SOCKET when scripted (self-test) */
+  int timeout;
+  socks5_test_io *io;
+} socks5_stream;
+
+static int socks5_fail(char *msg, size_t msgsize, const char *text) {
+  if (msgsize != 0)
+    strlcpybuff(msg, text, msgsize);
+  return 0;
+}
+
+/* Read exactly n bytes, or fail: SOCKS frames are not self-delimiting, so a
+   short read would desync the stream shared with the origin traffic. */
+static int socks5_read_n(socks5_stream *st, unsigned char *buf, size_t n) {
+  size_t got = 0;
+  int stalls = 0;
+
+  if (st->soc == INVALID_SOCKET) { /* scripted */
+    socks5_test_io *const io = st->io;
+
+    if (n > io->reply_len - io->consumed)
+      return 0;
+    memcpy(buf, io->reply + io->consumed, n);
+    io->consumed += n;
+    return 1;
+  }
+  while (got < n) {
+    const int r = (int) recv(st->soc, (char *) buf + got, (int) (n - got), 0);
+
+    if (r > 0) {
+      got += (size_t) r;
+      stalls = 0;
+    } else if (r == 0) {
+      return 0; // proxy closed mid-frame
+    } else {
+#ifdef _WIN32
+      const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+      const int wouldblock =
+          (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+      if (!wouldblock || !check_readinput_t(st->soc, st->timeout) ||
+          ++stalls > 100)
+        return 0;
+    }
+  }
+  return 1;
+}
+
+static int socks5_write_all(socks5_stream *st, const unsigned char *buf,
+                            size_t len) {
+  size_t remain = len;
+  int stalls = 0;
+
+  if (st->soc == INVALID_SOCKET) { /* scripted */
+    socks5_test_io *const io = st->io;
+
+    if (len > sizeof(io->sent) - io->sent_len)
+      return 0;
+    memcpy(io->sent + io->sent_len, buf, len);
+    io->sent_len += len;
+    return 1;
+  }
+  while (remain > 0) {
+    // raw send: the socket is still plain here, sendc() would route to TLS
+    const int n = (int) send(st->soc, (const char *) buf, (int) remain, 0);
+
+    if (n > 0) {
+      buf += n;
+      remain -= (size_t) n;
+      stalls = 0;
+    } else {
+#ifdef _WIN32
+      const int wouldblock = (WSAGetLastError() == WSAEWOULDBLOCK);
+#else
+      const int wouldblock =
+          (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR);
+#endif
+      if (!wouldblock || !check_writeinput_t(st->soc, st->timeout) ||
+          ++stalls > 100)
+        return 0;
+    }
+  }
+  return 1;
+}
+
+static const char *socks5_rep_message(unsigned char rep) {
+  switch (rep) {
+  case 0x01:
+    return "general failure";
+  case 0x02:
+    return "connection not allowed by ruleset";
+  case 0x03:
+    return "network unreachable";
+  case 0x04:
+    return "host unreachable";
+  case 0x05:
+    return "connection refused";
+  case 0x06:
+    return "TTL expired";
+  case 0x07:
+    return "command not supported";
+  case 0x08:
+    return "address type not supported";
+  default:
+    return "unknown error";
+  }
+}
+
+/* The reply's BND.ADDR is variable-length: consume exactly what ATYP says, or
+   the leftover bytes prepend to the first origin (or TLS) read. */
+static int socks5_read_reply(socks5_stream *st, char *msg, size_t msgsize) {
+  unsigned char head[4];
+  unsigned char addr[SOCKS5_MAXFIELD + 2];
+  size_t addrlen;
+
+  if (!socks5_read_n(st, head, sizeof(head)))
+    return socks5_fail(msg, msgsize, "SOCKS5: no reply from proxy");
+  if (head[0] != SOCKS5_VERSION)
+    return socks5_fail(msg, msgsize, "SOCKS5: bad version in reply");
+  if (head[1] != 0x00) {
+    snprintf(msg, msgsize, "SOCKS5 connect failed: %s",
+             socks5_rep_message(head[1]));
+    return 0;
+  }
+  switch (head[3]) {
+  case SOCKS5_ATYP_IPV4:
+    addrlen = 4;
+    break;
+  case SOCKS5_ATYP_IPV6:
+    addrlen = 16;
+    break;
+  case SOCKS5_ATYP_DOMAIN: {
+    unsigned char len;
+
+    if (!socks5_read_n(st, &len, 1))
+      return socks5_fail(msg, msgsize, "SOCKS5: truncated reply");
+    addrlen = len; // <= 255, always fits addr[]
+    break;
+  }
+  default: // unknown length: the stream cannot be resynchronized
+    return socks5_fail(msg, msgsize, "SOCKS5: unknown address type in reply");
+  }
+  if (addrlen != 0 && !socks5_read_n(st, addr, addrlen))
+    return socks5_fail(msg, msgsize, "SOCKS5: truncated reply address");
+  if (!socks5_read_n(st, addr, 2)) // BND.PORT, unused
+    return socks5_fail(msg, msgsize, "SOCKS5: truncated reply port");
+  return 1;
+}
+
+static int socks5_negotiate(socks5_stream *st, const char *host, size_t hostlen,
+                            int port, const char *user, size_t userlen,
+                            const char *pass, size_t passlen, int want_auth,
+                            char *msg, size_t msgsize) {
+  unsigned char frame[3 + SOCKS5_MAXFIELD + SOCKS5_MAXFIELD];
+  unsigned char rep[2];
+
+  /* greeting */
+  frame[0] = SOCKS5_VERSION;
+  frame[1] = (unsigned char) (want_auth ? 2 : 1);
+  frame[2] = SOCKS5_METHOD_NONE;
+  frame[3] = SOCKS5_METHOD_USERPASS;
+  if (!socks5_write_all(st, frame, (size_t) 2 + frame[1]))
+    return socks5_fail(msg, msgsize, "SOCKS5: write error");
+  if (!socks5_read_n(st, rep, sizeof(rep)))
+    return socks5_fail(msg, msgsize, "SOCKS5: no method reply from proxy");
+  if (rep[0] != SOCKS5_VERSION)
+    return socks5_fail(msg, msgsize, "SOCKS5: bad version in method reply");
+  switch (rep[1]) {
+  case SOCKS5_METHOD_NONE:
+    break;
+  case SOCKS5_METHOD_USERPASS:
+    if (!want_auth)
+      return socks5_fail(msg, msgsize,
+                         "SOCKS5: proxy requires authentication, none given");
+    /* RFC 1929 sub-negotiation; its version byte is 0x01, not 0x05 */
+    frame[0] = SOCKS5_AUTH_VERSION;
+    frame[1] = (unsigned char) userlen;
+    memcpy(frame + 2, user, userlen);
+    frame[2 + userlen] = (unsigned char) passlen;
+    memcpy(frame + 3 + userlen, pass, passlen);
+    if (!socks5_write_all(st, frame, 3 + userlen + passlen))
+      return socks5_fail(msg, msgsize, "SOCKS5: write error");
+    if (!socks5_read_n(st, rep, sizeof(rep)))
+      return socks5_fail(msg, msgsize, "SOCKS5: no authentication reply");
+    if (rep[1] != 0x00)
+      return socks5_fail(msg, msgsize, "SOCKS5: authentication failed");
+    break;
+  case SOCKS5_METHOD_NOACCEPTABLE:
+    return socks5_fail(
+        msg, msgsize,
+        "SOCKS5: proxy accepts no authentication method we offer");
+  default:
+    return socks5_fail(msg, msgsize,
+                       "SOCKS5: proxy selected an unknown method");
+  }
+
+  /* CONNECT to the origin, by name */
+  frame[0] = SOCKS5_VERSION;
+  frame[1] = SOCKS5_CMD_CONNECT;
+  frame[2] = 0x00; // RSV
+  frame[3] = SOCKS5_ATYP_DOMAIN;
+  frame[4] = (unsigned char) hostlen;
+  memcpy(frame + 5, host, hostlen);
+  frame[5 + hostlen] = (unsigned char) (port >> 8);
+  frame[6 + hostlen] = (unsigned char) (port & 0xFF);
+  if (!socks5_write_all(st, frame, 7 + hostlen))
+    return socks5_fail(msg, msgsize, "SOCKS5: write error");
+
+  return socks5_read_reply(st, msg, msgsize);
+}
+
+/* Decode the proxy userinfo into the two RFC 1929 fields. Split on the first
+   colon of the still-escaped string, so a %3A stays inside the username. */
+static int socks5_credentials(httrackp *opt, const char *proxy_name, char *user,
+                              size_t user_size, size_t *userlen, char *pass,
+                              size_t pass_size, size_t *passlen, char *msg,
+                              size_t msgsize) {
+  const char *const a = jump_identification_const(proxy_name); // past the '@'
+  const char *const astart = jump_protocol_const(proxy_name);
+  char userinfo[1024];
+  char *colon;
+
+  if (a <= astart || (size_t) (a - astart) - 1 >= sizeof(userinfo))
+    return socks5_fail(msg, msgsize, "SOCKS5: credentials too long");
+  userinfo[0] = '\0';
+  strncatbuff(userinfo, astart, (int) (a - astart) - 1);
+  colon = strchr(userinfo, ':');
+  if (colon != NULL)
+    *colon++ = '\0';
+  strlcpybuff(
+      user, unescape_http(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), userinfo),
+      user_size);
+  strlcpybuff(pass,
+              colon != NULL ? unescape_http(OPT_GET_BUFF(opt),
+                                            OPT_GET_BUFF_SIZE(opt), colon)
+                            : "",
+              pass_size);
+  *userlen = strlen(user);
+  *passlen = strlen(pass);
+  // reject, never truncate: a clipped secret would authenticate as another one
+  if (*userlen > SOCKS5_MAXFIELD || *passlen > SOCKS5_MAXFIELD)
+    return socks5_fail(msg, msgsize, "SOCKS5: credentials too long");
+  if (*userlen == 0)
+    return socks5_fail(msg, msgsize, "SOCKS5: empty proxy username");
+  return 1;
+}
+
+static int socks5_handshake_stream(httrackp *opt, socks5_stream *st,
+                                   const char *adr, const char *proxy_name,
+                                   int ssl, char *msg, size_t msgsize) {
+  const char *const host = jump_identification_const(adr);
+  const char *const portsep = jump_toport_const(adr);
+  const size_t hostlen =
+      portsep != NULL ? (size_t) (portsep - host) : strlen(host);
+  // sized for the whole userinfo: decoding shrinks, so an over-long credential
+  // lands intact and is rejected below rather than silently clipped
+  char user[1024];
+  char pass[1024];
+  size_t userlen = 0, passlen = 0;
+  int want_auth = 0;
+  int port = ssl ? 443 : 80;
+  size_t i;
+
+  if (hostlen == 0 || hostlen > SOCKS5_MAXFIELD)
+    return socks5_fail(msg, msgsize, "SOCKS5: invalid origin host");
+  if (host[0] == '[') // ATYP=domain cannot carry an IPv6 literal
+    return socks5_fail(msg, msgsize,
+                       "SOCKS5: IPv6 literal origin is not supported");
+  for (i = 0; i < hostlen; i++) {
+    if ((unsigned char) host[i] < ' ')
+      return socks5_fail(msg, msgsize, "SOCKS5: invalid origin host");
+  }
+  if (portsep != NULL) {
+    int p = -1;
+
+    sscanf(portsep + 1, "%d", &p);
+    if (p <= 0 || p > 65535)
+      return socks5_fail(msg, msgsize, "SOCKS5: invalid origin port");
+    port = p;
+  }
+  if (link_has_authorization(proxy_name)) {
+    if (!socks5_credentials(opt, proxy_name, user, sizeof(user), &userlen, pass,
+                            sizeof(pass), &passlen, msg, msgsize))
+      return 0;
+    want_auth = 1;
+  }
+  return socks5_negotiate(st, host, hostlen, port, user, userlen, pass, passlen,
+                          want_auth, msg, msgsize);
+}
+
+int socks5_handshake(httrackp *opt, htsblk *retour, const char *adr,
+                     int timeout) {
+  socks5_stream st;
+#if HTS_USEOPENSSL
+  const int ssl = retour->ssl;
+#else
+  const int ssl = 0;
+#endif
+
+  if (retour->soc == INVALID_SOCKET)
+    return 0;
+  st.soc = retour->soc;
+  st.timeout = timeout;
+  st.io = NULL;
+  return socks5_handshake_stream(opt, &st, adr, retour->req.proxy.name, ssl,
+                                 retour->msg, sizeof(retour->msg));
+}
+
+int socks5_handshake_scripted(httrackp *opt, const char *adr,
+                              const char *proxy_name, socks5_test_io *io) {
+  socks5_stream st;
+
+  st.soc = INVALID_SOCKET;
+  st.timeout = 0;
+  st.io = io;
+  io->consumed = 0;
+  io->sent_len = 0;
+  io->msg[0] = '\0';
+  return socks5_handshake_stream(opt, &st, adr, proxy_name, 0, io->msg,
+                                 sizeof(io->msg));
+}

src/htsproxy.h

@@ -0,0 +1,82 @@
+/* ------------------------------------------------------------ */
+/*
+HTTrack Website Copier, Offline Browser for Windows and Unix
+Copyright (C) 2026 Xavier Roche and other contributors
+
+SPDX-License-Identifier: GPL-3.0-or-later
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Ethical use: we kindly ask that you NOT use this software to harvest email
+addresses or to collect any other private information about people. Doing so
+would dishonor our work and waste the many hours we have spent on it.
+
+Please visit our Website: http://www.httrack.com
+*/
+
+/* ------------------------------------------------------------ */
+/* File: Proxy tunneling (HTTP CONNECT, SOCKS5) .h              */
+/* Author: Xavier Roche                                         */
+/* ------------------------------------------------------------ */
+
+#ifndef HTS_DEFPROXY
+#define HTS_DEFPROXY
+
+#include "htsglobal.h"
+
+/* Forward definitions */
+#ifndef HTS_DEF_FWSTRUCT_httrackp
+#define HTS_DEF_FWSTRUCT_httrackp
+typedef struct httrackp httrackp;
+#endif
+#ifndef HTS_DEF_FWSTRUCT_htsblk
+#define HTS_DEF_FWSTRUCT_htsblk
+typedef struct htsblk htsblk;
+#endif
+
+/* Open an HTTP CONNECT tunnel through the active proxy for an https request:
+   `retour->soc` must already be TCP-connected to the proxy, and `adr` is the
+   origin authority (url_adr, e.g. "https://host:port"). Sends the CONNECT
+   request (with Proxy-Authorization when the proxy carries credentials) and
+   reads the proxy's status line, so the caller's TLS handshake then runs
+   end-to-end with the origin. Blocks up to `timeout` seconds. Returns 1 on a
+   2xx tunnel, 0 on failure (retour->msg/statuscode set). */
+int http_proxy_tunnel(httrackp *opt, htsblk *retour, const char *adr,
+                      int timeout);
+
+/* SOCKS5 (RFC 1928, RFC 1929 auth) handshake on the raw proxy socket, before
+   any TLS: `retour->soc` must be TCP-connected to the proxy and `adr` is the
+   origin (url_adr). The origin name is sent verbatim (ATYP=domain), so the
+   proxy resolves it; a bracketed IPv6 literal origin is rejected. Blocks up to
+   `timeout` seconds. Returns 1 with the stream positioned on the first origin
+   byte, 0 on failure (retour->msg set). */
+int socks5_handshake(httrackp *opt, htsblk *retour, const char *adr,
+                     int timeout);
+
+/* Self-test hook (-#test=socks5): run the handshake against `reply`, a scripted
+   server byte stream, instead of a socket. `sent` captures the client frames,
+   `consumed` the reply bytes eaten (the frame-desync guard). */
+typedef struct socks5_test_io {
+  const unsigned char *reply;
+  size_t reply_len;
+  size_t consumed;
+  unsigned char sent[1024];
+  size_t sent_len;
+  char msg[256];
+} socks5_test_io;
+
+int socks5_handshake_scripted(httrackp *opt, const char *adr,
+                              const char *proxy_name, socks5_test_io *io);
+
+#endif

src/htsselftest.c

@@ -54,9 +54,14 @@ Please visit our Website: http://www.httrack.com
 #include "htsftp.h"
 #include "htsmd5.h"
 #include "htssniff.h"
+#include "htscodec.h"
+#include "htsproxy.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
 #endif
+#if HTS_USEZSTD
+#include <zstd.h>
+#endif
 #include "coucal/coucal.h"
 
 #include <ctype.h>
@@ -1304,6 +1309,162 @@ static int st_identurl(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+static int st_proxyurl(httrackp *opt, int argc, char **argv) {
+  char BIGSTK name[HTS_URLMAXSIZE * 2];
+  int port = -1;
+
+  (void) opt;
+  if (argc < 1) {
+    fprintf(stderr, "proxyurl: needs a proxy argument\n");
+    return 1;
+  }
+  hts_parse_proxy(argv[0], name, sizeof(name), &port);
+  // host= is what the connect actually resolves (scheme + user:pass stripped)
+  printf("name=%s port=%d host=%s\n", name, port,
+         jump_identification_const(name));
+  return 0;
+}
+
+/* Scripted SOCKS5 server: no-auth method reply, then a success CONNECT reply
+   carrying the given ATYP address, then a sentinel origin byte the handshake
+   must leave unread (an off-by-one in the reply framing eats it). */
+static size_t socks5_reply(unsigned char *buf, unsigned char atyp,
+                           const unsigned char *addr, size_t addrlen) {
+  size_t n = 0;
+
+  buf[n++] = 0x05;
+  buf[n++] = 0x00; /* method: no authentication */
+  buf[n++] = 0x05;
+  buf[n++] = 0x00; /* REP: succeeded */
+  buf[n++] = 0x00;
+  buf[n++] = atyp;
+  memcpy(buf + n, addr, addrlen);
+  n += addrlen;
+  buf[n++] = 0x1f;
+  buf[n++] = 0x90; /* BND.PORT */
+  buf[n++] = 0xAA; /* sentinel */
+  return n;
+}
+
+#define SOCKS5_SENTINEL_LEFT(io, len) ((io).consumed == (len) - 1)
+
+static int st_socks5(httrackp *opt, int argc, char **argv) {
+  static const unsigned char v4[4] = {127, 0, 0, 1};
+  static const unsigned char v6[16] = {0};
+  static const unsigned char domain[6] = {5, 'p', 'r', 'o', 'x', 'y'};
+  const char *const proxy = "socks5://127.0.0.1";
+  unsigned char script[64];
+  socks5_test_io io;
+  size_t len;
+
+  (void) argc;
+  (void) argv;
+
+  /* each reply address type is drained exactly, sentinel untouched */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+  /* the greeting offers no-auth only, and the origin goes out by name, port 80
+   */
+  assertf(io.sent_len == 3 + 7 + 11);
+  assertf(memcmp(io.sent, "\x05\x01\x00", 3) == 0);
+  assertf(memcmp(io.sent + 3, "\x05\x01\x00\x03\x0borigin.test\x00\x50", 18) ==
+          0);
+
+  len = socks5_reply(script, 0x04, v6, sizeof(v6));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+
+  len = socks5_reply(script, 0x03, domain, sizeof(domain));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 1);
+  assertf(SOCKS5_SENTINEL_LEFT(io, len));
+
+  /* an unknown address type has no known length: fail, never guess */
+  len = socks5_reply(script, 0x02, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* truncated frames (here: no BND.PORT) fail instead of over-reading */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4)) - 3;
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* explicit origin port is encoded big-endian (8443 = 0x20fb) */
+  len = socks5_reply(script, 0x01, v4, sizeof(v4));
+  io.reply = script;
+  io.reply_len = len;
+  assertf(socks5_handshake_scripted(opt, "origin.test:8443", proxy, &io) == 1);
+  assertf(memcmp(io.sent + io.sent_len - 2, "\x20\xfb", 2) == 0);
+
+  /* credentials: split on the first colon of the escaped userinfo, so %3a stays
+     inside the username and a colon in the password is not a delimiter */
+  {
+    static const unsigned char auth_script[] = {
+        0x05, 0x02,             /* method: user/pass */
+        0x01, 0x00,             /* auth: success */
+        0x05, 0x00, 0x00, 0x01, /* REP: succeeded, ATYP ipv4 */
+        127,  0,    0,    1,    0x1f, 0x90, 0xAA};
+
+    io.reply = auth_script;
+    io.reply_len = sizeof(auth_script);
+    assertf(socks5_handshake_scripted(opt, "origin.test",
+                                      "socks5://us%3aer:p:ass@127.0.0.1",
+                                      &io) == 1);
+    assertf(SOCKS5_SENTINEL_LEFT(io, sizeof(auth_script)));
+    assertf(memcmp(io.sent, "\x05\x02\x00\x02", 4) == 0);
+    assertf(memcmp(io.sent + 4, "\x01\x05us:er\x05p:ass", 13) == 0);
+  }
+
+  /* a proxy demanding auth we cannot provide, and one refusing every method */
+  io.reply = (const unsigned char *) "\x05\x02";
+  io.reply_len = 2;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+  io.reply = (const unsigned char *) "\x05\xff";
+  io.reply_len = 2;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* a refused CONNECT is an error, not a tunnel */
+  io.reply = (const unsigned char
+                  *) "\x05\x00\x05\x05\x00\x01\x7f\x00\x00\x01\x1f\x90";
+  io.reply_len = 12;
+  assertf(socks5_handshake_scripted(opt, "origin.test", proxy, &io) == 0);
+
+  /* over-long host or credentials are rejected before anything is sent */
+  {
+    char host[512];
+    char name[1024];
+    size_t i;
+
+    host[0] = '\0';
+    for (i = 0; i < 256; i++)
+      strcatbuff(host, "a");
+    io.reply = script;
+    io.reply_len = len;
+    assertf(socks5_handshake_scripted(opt, host, proxy, &io) == 0);
+    assertf(io.sent_len == 0);
+
+    strcpybuff(name, "socks5://user:");
+    for (i = 0; i < 256; i++)
+      strcatbuff(name, "p");
+    strcatbuff(name, "@127.0.0.1");
+    io.reply = script;
+    io.reply_len = len;
+    assertf(socks5_handshake_scripted(opt, "origin.test", name, &io) == 0);
+    assertf(io.sent_len == 0);
+  }
+
+  printf("socks5 self-test OK\n");
+  return 0;
+}
+
 /* Regression for the one-byte fil[] overflow: a 2047-byte hostless "?"-URL used
    to abort in strncat_safe_ when the missing leading '/' pushed fil to 2048. */
 static int st_identabs(httrackp *opt, int argc, char **argv) {
@@ -2305,6 +2466,7 @@ static int ae_write_collision(const char *path, const unsigned char *src,
   freet(buf);
   return ok ? 0 : 1;
 }
+#endif
 
 /* Write src[0..len) to path as-is; 0 on success. */
 static int ae_write_raw(const char *path, const unsigned char *src,
@@ -2338,17 +2500,22 @@ static int ae_check_decoded(const char *path, const unsigned char *expect,
   fclose(f);
   return (off == len) ? 0 : 1;
 }
-#endif
 
 /* Accept-Encoding (#450): advertise gzip+deflate; both decode (hts_zunpack) */
 static int st_acceptencoding(httrackp *opt, int argc, char **argv) {
-  const char *off = hts_acceptencoding(HTS_FALSE);
-  const char *on = hts_acceptencoding(HTS_TRUE);
+  const char *off = hts_acceptencoding(HTS_FALSE, HTS_TRUE);
+  const char *on = hts_acceptencoding(HTS_TRUE, HTS_FALSE);
+  const char *tls = hts_acceptencoding(HTS_TRUE, HTS_TRUE);
 
   (void) opt;
   assertf(strcmp(off, "identity") == 0);
   assertf(strstr(on, "gzip") != NULL);
   assertf(strstr(on, "deflate") != NULL); /* fails on the old gzip-only list */
+  /* br and zstd ride on TLS only, so a cleartext proxy can not be handed a
+     coding it may try to rewrite */
+  assertf(strstr(on, "br") == NULL && strstr(on, "zstd") == NULL);
+  assertf((strstr(tls, ", br") != NULL) == (HTS_USEBROTLI != 0));
+  assertf((strstr(tls, "zstd") != NULL) == (HTS_USEZSTD != 0));
 #if HTS_USEZLIB
   if (argc >= 1) {
     static const int windowBits[] = {16 + MAX_WBITS, MAX_WBITS, -MAX_WBITS};
@@ -2436,6 +2603,115 @@ static int st_acceptencoding(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+#if HTS_USEBROTLI
+/* No brotli encoder is linked, so the coded bytes are canned: brotli quality 9
+   over cc_text, and over 4 MiB of 'A' (14 bytes, ~300000x). */
+static const unsigned char cc_br_text[] = {
+    0x1b, 0x43, 0x00, 0x00, 0x44, 0xdd, 0x96, 0xea, 0xe8, 0x22, 0xdd, 0x90,
+    0xa4, 0x1b, 0x8a, 0xf7, 0x47, 0x0e, 0xc2, 0xc5, 0x3d, 0x09, 0x1b, 0x70,
+    0xe0, 0x1e, 0x60, 0xa0, 0x8b, 0xcc, 0xbe, 0xcb, 0xb0, 0x31, 0x76, 0x9e,
+    0xcf, 0x6e, 0x41, 0xb5, 0xe8, 0x2e, 0x56, 0x78, 0x08, 0x1b, 0xfa, 0x08,
+    0x8a, 0x50, 0x83, 0x4e, 0x62, 0x7f, 0xbf, 0x05, 0xf2, 0x22, 0x8f, 0xdf,
+    0x28, 0xdc, 0x9f, 0xa9, 0x90, 0x50, 0x37, 0x62, 0x56, 0x4f, 0xa8};
+static const unsigned char cc_br_bomb[] = {0x9b, 0xff, 0xff, 0x3f, 0x00,
+                                           0x24, 0x82, 0xe2, 0xb1, 0x40,
+                                           0x72, 0xef, 0x7f, 0x00};
+#endif
+
+static const unsigned char cc_text[] =
+    "content codings: HTTrack decodes gzip, brotli and zstd bodies alike.";
+
+/* Content codings: br and zstd decode, junk tokens stay identity, a coding we
+   can not undo fails the fetch, and a bomb never lands on disk. */
+static int st_contentcodings(httrackp *opt, int argc, char **argv) {
+  const size_t tlen = sizeof(cc_text) - 1;
+  char inpath[HTS_URLMAXSIZE], outpath[HTS_URLMAXSIZE];
+
+  (void) opt;
+  assertf(hts_codec_parse("gzip") == HTS_CODEC_DEFLATE);
+  assertf(hts_codec_parse("x-deflate") == HTS_CODEC_DEFLATE);
+  assertf(hts_codec_parse("") == HTS_CODEC_IDENTITY);
+  assertf(hts_codec_parse("identity") == HTS_CODEC_IDENTITY);
+  /* servers do label plain bodies with junk; the page must survive that */
+  assertf(hts_codec_parse("utf-8") == HTS_CODEC_IDENTITY);
+  /* a real coding with no decoder here: fail, never save the coded bytes */
+  assertf(hts_codec_parse("compress") == HTS_CODEC_UNSUPPORTED);
+  assertf(hts_codec_parse("br") ==
+          (HTS_USEBROTLI ? HTS_CODEC_BROTLI : HTS_CODEC_UNSUPPORTED));
+  assertf(hts_codec_parse("zstd") ==
+          (HTS_USEZSTD ? HTS_CODEC_ZSTD : HTS_CODEC_UNSUPPORTED));
+  assertf(hts_codec_is_archive_ext(HTS_CODEC_DEFLATE, "tgz"));
+  assertf(!hts_codec_is_archive_ext(HTS_CODEC_DEFLATE, "html"));
+  assertf(hts_codec_is_archive_ext(HTS_CODEC_BROTLI, "br"));
+  assertf(hts_codec_is_archive_ext(HTS_CODEC_ZSTD, "zst"));
+  /* decoded-size budget: 4096x, floor 1 MiB, ceiling INT_MAX */
+  assertf(hts_codec_maxout(1) == 1024 * 1024);
+  assertf(hts_codec_maxout(1024) == 4096 * 1024);
+  assertf(hts_codec_maxout(1024 * 1024) == INT_MAX);
+
+  if (argc >= 1) {
+    snprintf(inpath, sizeof(inpath), "%s/cc-in", argv[0]);
+    snprintf(outpath, sizeof(outpath), "%s/cc-out", argv[0]);
+#if HTS_USEBROTLI
+    {
+      unsigned char head[16];
+
+      assertf(ae_write_raw(inpath, cc_br_text, sizeof(cc_br_text)) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_BROTLI, inpath, outpath) ==
+              (int) tlen);
+      assertf(ae_check_decoded(outpath, cc_text, tlen) == 0);
+      assertf(hts_codec_head(HTS_CODEC_BROTLI, cc_br_text, sizeof(cc_br_text),
+                             head, sizeof(head)) == sizeof(head));
+      assertf(memcmp(head, cc_text, sizeof(head)) == 0);
+      /* truncated: must fail, not fall back to a verbatim copy */
+      assertf(ae_write_raw(inpath, cc_br_text, sizeof(cc_br_text) - 4) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_BROTLI, inpath, outpath) < 0);
+      /* cc_br_bomb is a valid stream that expands to 4 MiB; the budget, not a
+         corrupt frame, is what must reject it. */
+      assertf((LLint) (4 * 1024 * 1024) >
+              hts_codec_maxout((LLint) sizeof(cc_br_bomb)));
+      assertf(ae_write_raw(inpath, cc_br_bomb, sizeof(cc_br_bomb)) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_BROTLI, inpath, outpath) < 0);
+    }
+#endif
+#if HTS_USEZSTD
+    {
+      const size_t bomblen = 4 * 1024 * 1024;
+      const size_t bound = ZSTD_compressBound(bomblen);
+      unsigned char *bomb = malloct(bomblen);
+      unsigned char *zbuf = malloct(bound);
+      unsigned char head[16];
+      size_t zlen;
+
+      assertf(bomb != NULL && zbuf != NULL);
+      zlen = ZSTD_compress(zbuf, bound, cc_text, tlen, 6);
+      assertf(!ZSTD_isError(zlen));
+      assertf(ae_write_raw(inpath, zbuf, zlen) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_ZSTD, inpath, outpath) == (int) tlen);
+      assertf(ae_check_decoded(outpath, cc_text, tlen) == 0);
+      assertf(hts_codec_head(HTS_CODEC_ZSTD, zbuf, zlen, head, sizeof(head)) ==
+              sizeof(head));
+      assertf(memcmp(head, cc_text, sizeof(head)) == 0);
+      assertf(ae_write_raw(inpath, zbuf, zlen - 4) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_ZSTD, inpath, outpath) < 0);
+      memset(bomb, 'A', bomblen);
+      zlen = ZSTD_compress(zbuf, bound, bomb, bomblen, 6);
+      assertf(!ZSTD_isError(zlen));
+      /* the fixture must really be past the budget, whatever the ratio is */
+      assertf((LLint) bomblen > hts_codec_maxout((LLint) zlen));
+      assertf(ae_write_raw(inpath, zbuf, zlen) == 0);
+      assertf(hts_codec_unpack(HTS_CODEC_ZSTD, inpath, outpath) < 0);
+      freet(bomb);
+      freet(zbuf);
+    }
+#endif
+    /* a coding we can not undo yields no file at all */
+    assertf(hts_codec_unpack(HTS_CODEC_UNSUPPORTED, inpath, outpath) < 0);
+  }
+  printf("contentcodings self-test OK\n");
+  return 0;
+}
+
 /* Each call parses `txt` under a fresh host, then checkrobots() for `path`. */
 static int rb_decide(robots_wizard *r, const char *txt, const char *path) {
   static int n = 0;
@@ -2637,6 +2913,10 @@ static const struct selftest_entry {
     {"resolve", "<link> <adr> <fil>", "resolve a link against an origin",
      st_resolve},
     {"identurl", "<url>", "split an absolute URL into (adr, fil)", st_identurl},
+    {"proxyurl", "<proxy-arg>", "parse a -P proxy URL into host/port",
+     st_proxyurl},
+    {"socks5", "", "SOCKS5 handshake framing and credential self-test",
+     st_socks5},
     {"identabs", "", "ident_url_absolute one-byte fil[] overflow self-test",
      st_identabs},
     {"header", "<raw-header-line> ...", "response header-line parsing",
@@ -2677,6 +2957,9 @@ static const struct selftest_entry {
     {"status", "", "HTTP status code -> reason phrase self-test", st_status},
     {"acceptencoding", "[dir]",
      "Accept-Encoding advertises gzip+deflate, both decode", st_acceptencoding},
+    {"contentcodings", "[dir]",
+     "brotli and zstd bodies decode; bombs and unknown codings are refused",
+     st_contentcodings},
     {"robots", "", "robots.txt RFC 9309 Allow/Disallow precedence self-test",
      st_robots},
 #ifndef _WIN32

src/htszlib.c

@@ -37,6 +37,7 @@ Please visit our Website: http://www.httrack.com
 /* specific definitions */
 #include "htsbase.h"
 #include "htscore.h"
+#include "htscodec.h"
 #include "htszlib.h"
 
 #if HTS_USEZLIB
@@ -46,13 +47,8 @@ Please visit our Website: http://www.httrack.com
 #include "htszlib.h"
 */
 
-/*
-  Unpack file into a new file (gzip, zlib RFC1950 or raw deflate RFC1951).
-  A body provably in no deflate framing is copied verbatim (identity).
-  Return value: size of the new file, or -1 if an error occurred
-*/
 /* Note: utf-8 */
-int hts_zunpack(char *filename, char *newfile) {
+int hts_zunpack(const char *filename, const char *newfile) {
   int ret = -1;
 
   if (filename != NULL && newfile != NULL && filename[0] && newfile[0]) {
@@ -61,6 +57,7 @@ int hts_zunpack(char *filename, char *newfile) {
 
     if (in != NULL) {
       unsigned char BIGSTK inbuf[8192];
+      const LLint maxout = hts_codec_maxout(hts_codec_coded_size(in));
       size_t navail = fread(inbuf, 1, sizeof(inbuf), in);
       /* gzip/zlib headers -> +32 windowBits; else raw deflate (RFC1951) */
       const hts_boolean wrapped =
@@ -73,9 +70,10 @@ int hts_zunpack(char *filename, char *newfile) {
          deflate framing at all. env_error: local I/O or memory failure. */
       hts_boolean not_deflate = HTS_FALSE;
       hts_boolean env_error = HTS_FALSE;
+      hts_boolean bomb = HTS_FALSE;
 
       /* deflate is ambiguous; on failure retry with the other windowBits */
-      for (attempt = 0; attempt < 2 && ret < 0; attempt++) {
+      for (attempt = 0; attempt < 2 && ret < 0 && !bomb; attempt++) {
         const int windowBits =
             (attempt == 0 ? wrapped : !wrapped) ? (32 + MAX_WBITS) : -MAX_WBITS;
         FILE *fpout;
@@ -102,7 +100,7 @@ int hts_zunpack(char *filename, char *newfile) {
         }
         {
           hts_boolean ok = HTS_TRUE;
-          int size = 0;
+          LLint size = 0;
           int zerr = Z_OK;
 
           /* chunked inflate; first chunk in inbuf, single member */
@@ -126,27 +124,33 @@ int hts_zunpack(char *filename, char *newfile) {
                 break;
               }
               produced = sizeof(outbuf) - strm.avail_out;
+              size += (LLint) produced;
+              if (size > maxout) { /* decompression bomb: no retry, no copy */
+                bomb = HTS_TRUE;
+                ok = HTS_FALSE;
+                break;
+              }
               if (produced > 0 &&
                   fwrite(outbuf, 1, produced, fpout) != produced) {
                 env_error = HTS_TRUE;
                 ok = HTS_FALSE;
                 break;
               }
-              size += (int) produced;
             } while (strm.avail_out == 0);
             if (!ok || zerr == Z_STREAM_END)
               break;
             navail = fread(inbuf, 1, sizeof(inbuf), in);
           } while (navail > 0);
           if (ok && zerr == Z_STREAM_END)
-            ret = size;
+            ret = (int) size;
         }
         inflateEnd(&strm);
         fclose(fpout);
       }
       /* keep a mislabeled identity body verbatim only when provably not
          deflate; truncation or a local failure must keep failing (#47) */
-      if (ret < 0 && !wrapped && not_deflate && !env_error && !ferror(in)) {
+      if (ret < 0 && !bomb && !wrapped && not_deflate && !env_error &&
+          !ferror(in)) {
         FILE *const fpout =
             FOPEN(fconv(catbuff, sizeof(catbuff), newfile), "wb");
 
@@ -172,6 +176,25 @@ int hts_zunpack(char *filename, char *newfile) {
   return ret;
 }
 
+size_t hts_zhead(const void *in, size_t in_len, void *out, size_t out_len) {
+  z_stream zs;
+  size_t n = 0;
+  int err;
+
+  memset(&zs, 0, sizeof(zs));
+  if (inflateInit2(&zs, 47) != Z_OK) /* 47: gzip or zlib, autodetected */
+    return 0;
+  zs.next_in = (const Bytef *) in;
+  zs.avail_in = (uInt) in_len;
+  zs.next_out = (Bytef *) out;
+  zs.avail_out = (uInt) out_len;
+  err = inflate(&zs, Z_SYNC_FLUSH);
+  if (err == Z_OK || err == Z_STREAM_END || err == Z_BUF_ERROR)
+    n = out_len - zs.avail_out;
+  inflateEnd(&zs);
+  return n;
+}
+
 int hts_extract_meta(const char *path) {
   char catbuff[CATBUFF_SIZE];
   unzFile zFile = unzOpen(fconcat(catbuff, sizeof(catbuff), path, "hts-cache/new.zip"));

src/htszlib.h

@@ -44,7 +44,13 @@ Please visit our Website: http://www.httrack.com
 
 /* Library internal definictions */
 #ifdef HTS_INTERNAL_BYTECODE
-extern int hts_zunpack(char *filename, char *newfile);
+/* Inflate filename into newfile (gzip, zlib or raw deflate); decoded size, or
+   -1 on a corrupt/truncated stream, an over-budget body, or an I/O failure. A
+   body provably in no deflate framing is copied verbatim. */
+extern int hts_zunpack(const char *filename, const char *newfile);
+/* Inflate the head of a gzip/zlib stream, out_len max; 0 if undecodable */
+extern size_t hts_zhead(const void *in, size_t in_len, void *out,
+                        size_t out_len);
 extern int hts_extract_meta(const char *path);
 extern const char *hts_get_zerror(int err);
 #endif

src/httrack.rc

@@ -0,0 +1,5 @@
+// Version resource for httrack.exe, the command line program. See version.rc.
+#define VER_FILE_DESCRIPTION "HTTrack Website Copier (command line)"
+#define VER_ORIGINAL_FILENAME "httrack.exe"
+#define VER_FILETYPE VFT_APP
+#include "version.rc"

src/httrack.vcxproj

@@ -108,6 +108,9 @@
       <Project>{e76ad871-54c1-45e8-a657-6117adeffb46}</Project>
     </ProjectReference>
   </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="httrack.rc" />
+  </ItemGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
 </Project>

src/libhttrack.rc

@@ -0,0 +1,5 @@
+// Version resource for libhttrack.dll. See version.rc.
+#define VER_FILE_DESCRIPTION "HTTrack Website Copier engine"
+#define VER_ORIGINAL_FILENAME "libhttrack.dll"
+#define VER_FILETYPE VFT_DLL
+#include "version.rc"

src/libhttrack.vcxproj

@@ -59,15 +59,17 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <!-- LIBHTTRACK_EXPORTS turns HTSEXT_API into __declspec(dllexport); ZLIB_DLL
-           imports zlib from its DLL. Windows 7 floor, matching WinHTTrack. -->
-      <PreprocessorDefinitions>WIN32;_WINDOWS;_MBCS;_USRDLL;LIBHTTRACK_EXPORTS;ZLIB_DLL;WINVER=0x0601;_WIN32_WINNT=0x0601;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_DEPRECATE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+           imports zlib from its DLL. HTS_USEBROTLI/HTS_USEZSTD enable the br and
+           zstd content codings. Windows 7 floor, matching WinHTTrack. -->
+      <PreprocessorDefinitions>WIN32;_WINDOWS;_MBCS;_USRDLL;LIBHTTRACK_EXPORTS;ZLIB_DLL;HTS_USEBROTLI=1;HTS_USEZSTD=1;WINVER=0x0601;_WIN32_WINNT=0x0601;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_DEPRECATE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory);$(MSBuildThisFileDirectory)coucal;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <WarningLevel>Level3</WarningLevel>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <CompileAs>CompileAsC</CompileAs>
     </ClCompile>
     <Link>
-      <!-- vcpkg auto-links libssl/libcrypto/zlib; only the OS import lib is explicit. -->
+      <!-- vcpkg auto-links libssl/libcrypto/zlib/brotli/zstd; only the OS import
+           lib is explicit. -->
       <AdditionalDependencies>Ws2_32.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <GenerateDebugInformation>true</GenerateDebugInformation>
     </Link>
@@ -107,6 +109,7 @@
     <ClCompile Include="htscache_selftest.c" />
     <ClCompile Include="htscatchurl.c" />
     <ClCompile Include="htscharset.c" />
+    <ClCompile Include="htscodec.c" />
     <ClCompile Include="htsconcat.c" />
     <ClCompile Include="htscore.c" />
     <ClCompile Include="htscoremain.c" />
@@ -122,6 +125,7 @@
     <ClCompile Include="htsmodules.c" />
     <ClCompile Include="htsname.c" />
     <ClCompile Include="htsparse.c" />
+    <ClCompile Include="htsproxy.c" />
     <ClCompile Include="htsrobots.c" />
     <ClCompile Include="htsselftest.c" />
     <ClCompile Include="htssniff.c" />
@@ -138,6 +142,9 @@
     <ClCompile Include="minizip\zip.c" />
     <ClCompile Include="punycode.c" />
   </ItemGroup>
+  <ItemGroup>
+    <ResourceCompile Include="libhttrack.rc" />
+  </ItemGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
 </Project>

src/vcpkg.json

@@ -1,9 +1,12 @@
 {
-  "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
+  "$schema":
+      "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
   "name": "libhttrack",
   "version-string": "3.49",
   "dependencies": [
+    "brotli",
     "openssl",
-    "zlib"
+    "zlib",
+    "zstd"
   ]
 }

src/version.rc

@@ -0,0 +1,50 @@
+// Version resource for libhttrack.dll and httrack.exe. Signing enforces that every
+// binary in a release names the same product and version, so both need one.
+// Spelled out here because a VERSIONINFO cannot take a version string apart;
+// tests/01_engine-version-macros.test fails if this drifts from htsglobal.h.
+// The per-binary parts come from libhttrack.rc / httrack.rc.
+
+#include <winver.h>
+
+#ifndef VER_FILE_DESCRIPTION
+#define VER_FILE_DESCRIPTION "HTTrack Website Copier"
+#endif
+#ifndef VER_ORIGINAL_FILENAME
+#define VER_ORIGINAL_FILENAME ""
+#endif
+#ifndef VER_FILETYPE
+#define VER_FILETYPE VFT_APP
+#endif
+
+VS_VERSION_INFO VERSIONINFO
+  FILEVERSION 3, 49, 12, 0
+  PRODUCTVERSION 3, 49, 12, 0
+  FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
+#ifdef _DEBUG
+  FILEFLAGS VS_FF_DEBUG
+#else
+  FILEFLAGS 0x0L
+#endif
+  FILEOS VOS_NT_WINDOWS32
+  FILETYPE VER_FILETYPE
+  FILESUBTYPE VFT2_UNKNOWN
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904b0"  // U.S. English, Unicode
+    BEGIN
+      VALUE "CompanyName", "Xavier Roche"
+      VALUE "FileDescription", VER_FILE_DESCRIPTION
+      VALUE "FileVersion", "3.49.12"
+      VALUE "InternalName", VER_ORIGINAL_FILENAME
+      VALUE "LegalCopyright", "Copyright (C) 1998-2026 Xavier Roche and other contributors. GNU GPL v3 or later."
+      VALUE "OriginalFilename", VER_ORIGINAL_FILENAME
+      VALUE "ProductName", "HTTrack Website Copier"
+      VALUE "ProductVersion", "3.49-12"
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x409, 1200
+  END
+END

tests/01_engine-proxyurl.test

@@ -0,0 +1,44 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# hts_parse_proxy splits a -P argument "[scheme://][user:pass@]host[:port]" into
+# the proxy host string and port. -#test=proxyurl <arg> prints
+# "name=.. port=.. host=..", where host= is what the connect resolves.
+
+p() {
+    test "$(httrack -O /dev/null -#test=proxyurl "$1")" == "$2" || exit 1
+}
+
+# bare host, with and without an explicit port
+p 'proxy.example.com:8080' 'name=proxy.example.com port=8080 host=proxy.example.com'
+p 'proxy.example.com' 'name=proxy.example.com port=8080 host=proxy.example.com'
+
+# user:pass@ is kept in name (for proxy auth) and stripped from host
+p 'user:pass@proxy:3128' 'name=user:pass@proxy port=3128 host=proxy'
+p 'user:pass@proxy' 'name=user:pass@proxy port=8080 host=proxy'
+
+# a scheme colon must not be read as a port: http://host with no port used to
+# parse to name=http with a garbage port
+p 'http://proxy:8080' 'name=http://proxy port=8080 host=proxy'
+p 'http://proxy' 'name=http://proxy port=8080 host=proxy'
+
+# socks5/socks5h default to 1080 and resolve to the bare host
+p 'socks5://host:1080' 'name=socks5://host port=1080 host=host'
+p 'socks5://host' 'name=socks5://host port=1080 host=host'
+p 'socks5h://host' 'name=socks5h://host port=1080 host=host'
+# explicit port wins over the 1080 default, with and without userinfo
+p 'socks5://host:9050' 'name=socks5://host port=9050 host=host'
+p 'socks5://user:pass@host:9050' 'name=socks5://user:pass@host port=9050 host=host'
+
+# the split is byte-transparent: percent-escapes stay encoded (decoded later at
+# auth time), only structural ASCII ':'/'@' delimit, and the last '@' ends the
+# userinfo. So %40/%3A and UTF-8 bytes never mis-split host or port.
+p 'socks5://user:p%40ss@host:1080' 'name=socks5://user:p%40ss@host port=1080 host=host'
+p 'socks5://us%3Aer:pass@host:1080' 'name=socks5://us%3Aer:pass@host port=1080 host=host'
+p 'socks5://a@b:c@host:1080' 'name=socks5://a@b:c@host port=1080 host=host'
+p 'socks5://naïve:pass@héllo:1080' 'name=socks5://naïve:pass@héllo port=1080 host=héllo'
+
+# a lone ':' must not underflow the backward scan
+p ':' 'name= port=8080 host='

tests/01_engine-sniff.test

@@ -35,7 +35,8 @@ chk image/avif hex:0000001C6674797061766966 "$yes"
 chk image/avif hex:0000001C6674797068656963 "$no" # heic brand is not avif
 chk image/heic hex:0000001C6674797068656963 "$yes"
 chk image/svg+xml '<svg xmlns="x">' "$yes"
-chk image/svg+xml $'\xef\xbb\xbf  <?xml version="1.0"?>' "$yes" # BOM+ws skip
+# BOM+ws skip; hex, as Windows argv cannot carry the raw BOM through the ANSI codepage
+chk image/svg+xml hex:EFBBBF20203C3F786D6C2076657273696F6E3D22312E30223F3E "$yes"
 
 # audio / video
 chk audio/mpeg 'ID3xxx' "$yes"

tests/01_engine-socks5.test

@@ -0,0 +1,9 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# The SOCKS5 handshake framing and credential split, driven against scripted
+# server replies (frame draining, oversize rejects, RFC 1929 fields).
+
+httrack -O /dev/null '-#test=socks5' | grep -q "socks5 self-test OK"

tests/01_engine-version-macros.test

@@ -0,0 +1,64 @@
+#!/bin/bash
+#
+# version.rc repeats the version that htsglobal.h declares. Signing enforces that
+# every binary in a release reports the same one, so a drift fails the signing
+# request on release day rather than the build. Assert the two agree.
+
+set -euo pipefail
+
+src="${top_srcdir:-..}/src"
+h="$src/htsglobal.h"
+rc="$src/version.rc"
+for f in "$h" "$rc"; do
+    [ -f "$f" ] || {
+        echo "cannot find $f"
+        exit 1
+    }
+done
+
+# 3.49-12 (display) and 3.49.12 (dotted).
+version=$(sed -n 's/^#define HTTRACK_VERSION[[:space:]][[:space:]]*"\([^"]*\)".*/\1/p' "$h")
+versionid=$(sed -n 's/^#define HTTRACK_VERSIONID[[:space:]][[:space:]]*"\([^"]*\)".*/\1/p' "$h")
+if [ -z "$version" ] || [ -z "$versionid" ]; then
+    echo "could not read the version from $h"
+    exit 1
+fi
+
+# The same version, as version.rc states it.
+fileversion=$(sed -n 's/^[[:space:]]*FILEVERSION[[:space:]][[:space:]]*\(.*\)$/\1/p' "$rc" | tr -d ' \r')
+productversion=$(sed -n 's/^[[:space:]]*PRODUCTVERSION[[:space:]][[:space:]]*\(.*\)$/\1/p' "$rc" | tr -d ' \r')
+rc_fileversion=$(sed -n 's/.*VALUE "FileVersion",[[:space:]]*"\([^"]*\)".*/\1/p' "$rc")
+rc_productversion=$(sed -n 's/.*VALUE "ProductVersion",[[:space:]]*"\([^"]*\)".*/\1/p' "$rc")
+rc_productname=$(sed -n 's/.*VALUE "ProductName",[[:space:]]*"\([^"]*\)".*/\1/p' "$rc")
+
+# 3.49.12 -> 3,49,12,0
+expected_numeric="$(echo "$versionid" | tr '.' ','),0"
+
+fail=0
+check() { # what expected actual
+    if [ "$2" != "$3" ]; then
+        echo "version.rc $1 is \"$3\", but htsglobal.h says it should be \"$2\""
+        fail=1
+    fi
+}
+check FILEVERSION "$expected_numeric" "$fileversion"
+check PRODUCTVERSION "$expected_numeric" "$productversion"
+check FileVersion "$versionid" "$rc_fileversion"
+check ProductVersion "$version" "$rc_productversion"
+
+# Signing pins the product name too.
+check ProductName "HTTrack Website Copier" "$rc_productname"
+
+[ "$fail" -eq 0 ] || exit 1
+
+# And the shipped binary must agree with the header it was built from.
+out=$(httrack --version)
+case "$out" in
+*"$version"*) ;;
+*)
+    echo "httrack --version says \"$out\", which does not mention $version"
+    exit 1
+    ;;
+esac
+
+echo "version resource agrees with htsglobal.h: $version ($expected_numeric)"

tests/01_zlib-contentcodings.test

@@ -0,0 +1,11 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# brotli/zstd decode, unknown codings, and the decoded-size budget.
+dir=$(mktemp -d)
+trap 'rm -rf "$dir"' EXIT
+
+httrack -O /dev/null -#test=contentcodings "$dir" run |
+    grep -q "contentcodings self-test OK"

tests/50_local-contentcodings.test

@@ -0,0 +1,38 @@
+#!/bin/bash
+#
+# br and zstd on the wire: both decode, a junk coding leaves the body alone, an
+# undecodable one fails the fetch, and br/zstd are advertised over TLS only.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+# Both decoders are needed for the wire fixtures; the codec-off matrix is
+# covered by the fenced 01_zlib-contentcodings self-test.
+if test "${BROTLI_ENABLED:-yes}" != "yes" || test "${ZSTD_ENABLED:-yes}" != "yes"; then
+    echo "brotli/zstd not both compiled, skipping"
+    exit 77
+fi
+
+# bad.html (in memory) and bin.dat (direct-to-disk) both carry an undecodable
+# coding: the fetch fails and neither leaves coded bytes on disk.
+bash "$top_srcdir/tests/local-crawl.sh" --errors 2 --files 5 \
+    --file-matches 'codec/br.html' 'coded body' \
+    --file-matches 'codec/zstd.html' 'coded body' \
+    --file-matches 'codec/junk.html' 'junk coding' \
+    --file-matches 'codec/ae.html' 'AE=gzip, deflate,' \
+    --file-not-matches 'codec/ae.html' ' br' \
+    --file-not-matches 'codec/ae.html' 'zstd' \
+    --not-found 'codec/bad.html' \
+    --not-found 'codec/bin.dat' \
+    --log-found 'Unsupported Content-Encoding' \
+    httrack 'BASEURL/codec/index.html'
+
+if test "${HTTPS_SUPPORT:-}" == "no"; then
+    echo "no https support compiled, skipping the TLS leg"
+    exit 0
+fi
+
+bash "$top_srcdir/tests/local-crawl.sh" --tls --errors 2 --files 5 \
+    --file-matches 'codec/ae.html' 'AE=gzip, deflate, br, zstd,' \
+    httrack 'BASEURL/codec/index.html'

tests/51_local-update-codec.test

@@ -0,0 +1,38 @@
+#!/bin/bash
+#
+# A coded re-fetch that fails to decode must not destroy the mirrored file (#557).
+# Pass 1 mirrors from valid gzip; pass 2 (--update) serves an undecodable body for
+# mem.html (in-memory), disk.bin (direct-to-disk) and unsup.html (a coding we have
+# no decoder for). All three must keep their pass-1 content. fresh.html and
+# freshdisk.bin decode on both passes: they are the controls that a good update
+# still lands, in memory and direct-to-disk (the latter renaming the decoded temp
+# over an existing file). Unfixed, the decode target is the mirror itself, so the
+# first three are lost.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+# A restrictive umask makes the decoded direct-to-disk file's mode observable:
+# it is committed by renaming a temp, so it needs the chmod filecreate() does.
+umask 077
+
+bash "$top_srcdir/tests/local-crawl.sh" \
+    --rerun-args '--update' \
+    --errors 3 \
+    --log-found 'decompressing.*upcodec/mem\.html' \
+    --log-found 'decompressing.*upcodec/disk\.bin' \
+    --log-found 'Unsupported Content-Encoding.*upcodec/unsup\.html' \
+    --file-matches 'upcodec/mem.html' 'MIRRORED-MEM-V1' \
+    --file-matches 'upcodec/disk.bin' 'MIRRORED-DISK-V1' \
+    --file-min-bytes 'upcodec/disk.bin' 32768 \
+    --file-mode 'upcodec/disk.bin' 644 \
+    --file-matches 'upcodec/unsup.html' 'MIRRORED-UNSUP-V1' \
+    --file-matches 'upcodec/fresh.html' 'FRESH-V2' \
+    --file-not-matches 'upcodec/fresh.html' 'FRESH-V1' \
+    --file-mode 'upcodec/fresh.html' 644 \
+    --file-matches 'upcodec/freshdisk.bin' 'FRESHDISK-V2' \
+    --file-not-matches 'upcodec/freshdisk.bin' 'FRESHDISK-V1' \
+    --file-min-bytes 'upcodec/freshdisk.bin' 32768 \
+    --file-mode 'upcodec/freshdisk.bin' 644 \
+    httrack 'BASEURL/upcodec/index.html'

tests/52_local-socks5.test

@@ -0,0 +1,211 @@
+#!/bin/bash
+#
+# Issue #563: a SOCKS5 proxy must carry both http and https, resolve the origin
+# name REMOTELY (ATYP=domain, never a local lookup), and authenticate per RFC
+# 1929 without leaking the credentials to the origin.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+if test "${HTTPS_SUPPORT:-}" == "no"; then
+    echo "no https support compiled, skipping"
+    exit 77
+fi
+if ! command -v python3 >/dev/null 2>&1 || ! command -v openssl >/dev/null 2>&1; then
+    echo "python3/openssl missing, skipping"
+    exit 77
+fi
+
+# a .invalid name never resolves (RFC 6761): reaching the page at all proves the
+# proxy did the DNS
+host="socks-origin.invalid"
+server="$top_srcdir/tests/socks5-server.py"
+tmpdir=$(mktemp -d)
+pids=
+
+cleanup() {
+    for pid in $pids; do
+        kill "$pid" 2>/dev/null || true
+    done
+    rm -rf "$tmpdir"
+}
+trap cleanup EXIT
+
+openssl req -x509 -newkey rsa:2048 -keyout "$tmpdir/key.pem" \
+    -out "$tmpdir/cert.pem" -days 2 -nodes -subj "/CN=127.0.0.1" \
+    >/dev/null 2>&1
+cat "$tmpdir/key.pem" "$tmpdir/cert.pem" >"$tmpdir/both.pem"
+
+# start_server <logdir> <mode>: sets $tls_port/$http_port/$socks_port
+start_server() {
+    local dir="$1" mode="$2" ports
+    mkdir -p "$dir"
+    ports="$dir/ports.txt"
+    python3 "$server" "$tmpdir/both.pem" "$dir" "$mode" \
+        >"$ports" 2>"$dir/server.err" &
+    pids="$pids $!"
+    for _ in $(seq 1 100); do
+        grep -q "^ready" "$ports" 2>/dev/null && break
+        sleep 0.1
+    done
+    grep -q "^ready" "$ports" 2>/dev/null || {
+        echo "server ($mode) did not start" >&2
+        cat "$dir/server.err" >&2
+        exit 1
+    }
+    tls_port=$(awk '/^TLS/{print $2}' "$ports")
+    http_port=$(awk '/^HTTP/{print $2}' "$ports")
+    socks_port=$(awk '/^SOCKS/{print $2}' "$ports")
+}
+
+# kill a hung httrack so a missing read bound surfaces as $HANG_RC instead of
+# stalling the job (macOS has no `timeout`)
+HANG_RC=137 # 128 + SIGKILL
+run_crawl() {
+    local out="$1" url="$2" proxy="$3"
+    shift 3
+    local extra="$*"
+    test -n "$extra" || extra="-r1 -s0"
+    rm -rf "$out"
+    # shellcheck disable=SC2086
+    httrack "$url" --proxy "$proxy" \
+        -O "$out" $extra --timeout=10 >"$out.log" 2>&1 &
+    local pid=$!
+    (sleep 60 && kill -9 "$pid" 2>/dev/null) &
+    local guard=$!
+    local rc=0
+    wait "$pid" 2>/dev/null || rc=$?
+    kill "$guard" 2>/dev/null || true
+    wait "$guard" 2>/dev/null || true
+    return "$rc"
+}
+
+# --- https over socks, remote DNS -------------------------------------------
+ok="$tmpdir/ok"
+start_server "$ok" ok
+
+run_crawl "$ok/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$ok/out" || {
+    echo "FAIL: origin page not downloaded through the socks proxy" >&2
+    cat "$ok/out.log" "$ok/server.err" >&2
+    exit 1
+}
+grep -q "^ATYP domain ${host}\$" "$ok/socks.log" || {
+    echo "FAIL: proxy did not receive ATYP=domain ${host} (no remote DNS)" >&2
+    cat "$ok/socks.log" >&2
+    exit 1
+}
+# a client that resolved locally would have sent an address, not a name
+grep -q "^ATYP ipv4" "$ok/socks.log" && {
+    echo "FAIL: httrack resolved locally and sent an IPv4 to the proxy" >&2
+    cat "$ok/socks.log" >&2
+    exit 1
+}
+echo "OK: https tunneled through socks5 with remote DNS"
+
+# --- plain http over socks --------------------------------------------------
+: >"$ok/origin-headers.log" # the https crawl above also logged a request line
+run_crawl "$ok/outh" "http://${host}:${http_port}/" "socks5://127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$ok/outh" || {
+    echo "FAIL: plain http not tunneled through the socks proxy" >&2
+    cat "$ok/outh.log" "$ok/socks.log" >&2
+    exit 1
+}
+# the tunneled request is origin-form, as on a direct connection: the http-proxy
+# absolute URI would reach the origin as "GET http://host/"
+grep -q "^REQUEST GET / " "$ok/origin-headers.log" || {
+    echo "FAIL: tunneled request is not origin-form" >&2
+    cat "$ok/origin-headers.log" >&2
+    exit 1
+}
+grep -q "^REQUEST GET http" "$ok/origin-headers.log" && {
+    echo "FAIL: absolute-URI request sent through the socks tunnel" >&2
+    cat "$ok/origin-headers.log" >&2
+    exit 1
+}
+echo "OK: plain http tunneled through socks5"
+
+# --- keep-alive socket reuse must NOT re-run the handshake ------------------
+# A reused keep-alive socket is already tunneled; re-injecting the SOCKS
+# greeting corrupts the origin stream. -c1 + the origin's max>1 advert makes
+# httrack serve the whole plain-http crawl over one tunnel: exactly one
+# handshake, every subpage intact.
+ka="$tmpdir/ka"
+start_server "$ka" ok
+run_crawl "$ka/out" "http://${host}:${http_port}/" "socks5://127.0.0.1:${socks_port}" -r3 -c1
+missing=0
+for i in 1 2 3 4 5; do
+    grep -rq "SUBPAGE-563 /p${i}.html" "$ka/out" || missing=1
+done
+test "$missing" -eq 0 || {
+    echo "FAIL: a keep-alive subpage was lost (re-handshake corrupted the reused socket)" >&2
+    cat "$ka/out.log" "$ka/socks.log" >&2
+    exit 1
+}
+handshakes=$(grep -c "^CMD " "$ka/socks.log" || true)
+test "$handshakes" -eq 1 || {
+    echo "FAIL: expected 1 SOCKS handshake for the reused socket, got $handshakes" >&2
+    cat "$ka/socks.log" >&2
+    exit 1
+}
+echo "OK: keep-alive socket reused over one socks tunnel, no re-handshake"
+
+# --- authenticated socks (RFC 1929) -----------------------------------------
+# over plain http: that is the request an http proxy would decorate with
+# Proxy-Authorization, so the no-leak check below has teeth
+auth="$tmpdir/auth"
+start_server "$auth" ok
+run_crawl "$auth/out" "http://${host}:${http_port}/" \
+    "socks5://user:secret@127.0.0.1:${socks_port}"
+grep -rq "ORIGIN-PAGE-563" "$auth/out" || {
+    echo "FAIL: origin not downloaded through the authenticated socks proxy" >&2
+    cat "$auth/out.log" "$auth/socks.log" >&2
+    exit 1
+}
+grep -q "^METHOD userpass\$" "$auth/socks.log" || {
+    echo "FAIL: user/pass method not negotiated (auth ignored)" >&2
+    cat "$auth/socks.log" >&2
+    exit 1
+}
+grep -q "^AUTH user secret\$" "$auth/socks.log" || {
+    echo "FAIL: wrong socks credentials sent" >&2
+    cat "$auth/socks.log" >&2
+    exit 1
+}
+grep -qi "secret\|proxy-authorization" "$auth/origin-headers.log" && {
+    echo "FAIL: socks credentials leaked into the origin request" >&2
+    cat "$auth/origin-headers.log" >&2
+    exit 1
+}
+echo "OK: socks5 user/pass negotiated, creds not leaked to origin"
+
+# --- hostile: refusing proxy ------------------------------------------------
+ref="$tmpdir/refuse"
+start_server "$ref" refuse
+rc=0
+run_crawl "$ref/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}" || rc=$?
+test "$rc" -ne "$HANG_RC" || {
+    echo "FAIL: crawl hung on a refusing socks proxy" >&2
+    exit 1
+}
+grep -rq "ORIGIN-PAGE-563" "$ref/out" 2>/dev/null && {
+    echo "FAIL: refusing proxy unexpectedly served the page" >&2
+    exit 1
+}
+echo "OK: refusing socks proxy fails cleanly, no hang"
+
+# --- hostile: truncated handshake reply -------------------------------------
+trunc="$tmpdir/trunc"
+start_server "$trunc" truncate
+rc=0
+run_crawl "$trunc/out" "https://${host}:${tls_port}/" "socks5://127.0.0.1:${socks_port}" || rc=$?
+test "$rc" -ne "$HANG_RC" || {
+    echo "FAIL: crawl hung on a truncated socks reply (bounded read missing)" >&2
+    exit 1
+}
+grep -rq "ORIGIN-PAGE-563" "$trunc/out" 2>/dev/null && {
+    echo "FAIL: truncated-reply proxy unexpectedly served the page" >&2
+    exit 1
+}
+echo "OK: bounded socks handshake, no hang on a truncated reply"

tests/Makefile.am

@@ -2,7 +2,7 @@
 # explicitly: automake does not expand wildcards in EXTRA_DIST, so a glob would
 # silently drop it from the dist tarball and break "make distcheck".
 EXTRA_DIST = $(TESTS) crawl-test.sh run-all-tests.sh check-network.sh \
-	proxy-https-server.py \
+	proxy-https-server.py socks5-server.py \
 	local-crawl.sh local-server.py server.crt server.key \
 	server-root/simple/basic.html server-root/simple/link.html \
 	server-root/stripquery/index.html server-root/stripquery/a.html \
@@ -15,6 +15,8 @@ TESTS_ENVIRONMENT += PATH=$(top_builddir)/src$(PATH_SEPARATOR)$$PATH
 ### TESTS_ENVIRONMENT += $(SHLIBPATH_VAR)="$(top_builddir)/src/$(LT_CV_OBJDIR)$${$(SHLIBPATH_VAR):+$(PATH_SEPARATOR)}$$$(SHLIBPATH_VAR)"
 TESTS_ENVIRONMENT += ONLINE_UNIT_TESTS=$(ONLINE_UNIT_TESTS)
 TESTS_ENVIRONMENT += HTTPS_SUPPORT=$(HTTPS_SUPPORT)
+TESTS_ENVIRONMENT += BROTLI_ENABLED=$(BROTLI_ENABLED)
+TESTS_ENVIRONMENT += ZSTD_ENABLED=$(ZSTD_ENABLED)
 TESTS_ENVIRONMENT += V6_SUPPORT=$(V6_SUPPORT)
 TESTS_ENVIRONMENT += top_srcdir=$(top_srcdir)
 
@@ -44,6 +46,8 @@ TESTS = \
 	01_engine-header.test \
 	01_engine-idna.test \
 	01_engine-identurl.test \
+	01_engine-proxyurl.test \
+	01_engine-socks5.test \
 	01_engine-identabs.test \
 	01_engine-escape-room.test \
 	01_engine-inplace-escape.test \
@@ -66,8 +70,10 @@ TESTS = \
 	01_engine-urlhack.test \
 	01_engine-unescape-bounds.test \
 	01_engine-useragent.test \
+	01_engine-version-macros.test \
 	01_engine-xfread.test \
 	01_zlib-acceptencoding.test \
+	01_zlib-contentcodings.test \
 	01_zlib-cache.test \
 	01_zlib-cache-corrupt.test \
 	01_zlib-cache-legacy.test \
@@ -119,6 +125,9 @@ TESTS = \
 	46_local-update-304-resume.test \
 	47_local-crange-overflow.test \
 	48_local-crange-memresume.test \
-	49_local-cookiewall.test
+	49_local-cookiewall.test \
+	50_local-contentcodings.test \
+	51_local-update-codec.test \
+	52_local-socks5.test
 
 CLEANFILES = check-network_sh.cache

tests/local-crawl.sh

@@ -17,7 +17,7 @@
 #       --errors N --errors-content N --files N --found PATH ... --directory PATH ... \
 #       --log-found REGEX ... --log-not-found REGEX ... \
 #       --file-matches PATH REGEX ... --file-not-matches PATH REGEX ... \
-#       --file-min-bytes PATH N --max-mirror-bytes N \
+#       --file-min-bytes PATH N --file-mode PATH OCTAL --max-mirror-bytes N \
 #       httrack BASEURL/some/path [httrack-args...]
 # --errors counts every "Error:" log line; --errors-content drops transient
 # network failures (codes -2..-6) that flake on busy loopback under -c8.
@@ -26,6 +26,7 @@
 # --file-matches/--file-not-matches grep (ERE) a mirrored file (PATH under the
 # host root), to assert rewritten link/content survived the crawl.
 # --file-min-bytes asserts a mirrored file (PATH) is at least N bytes.
+# --file-mode asserts its octal permissions (e.g. 644); POSIX hosts only.
 # --rerun-args runs a second pass (same server and mirror dir) with the given
 # extra httrack args appended, e.g. an --update run under a cap.
 # --cookie writes a Netscape cookies.txt (scoped to the discovered host:port,
@@ -141,7 +142,7 @@ while test "$pos" -lt "$nargs"; do
         audit+=("${args[$pos]}" "${args[$((pos + 1))]}")
         pos=$((pos + 1))
         ;;
-    --file-matches | --file-not-matches | --file-min-bytes)
+    --file-matches | --file-not-matches | --file-min-bytes | --file-mode)
         audit+=("${args[$pos]}" "${args[$((pos + 1))]}" "${args[$((pos + 2))]}")
         pos=$((pos + 2))
         ;;
@@ -319,9 +320,10 @@ done
 test -n "$hostroot" || die "could not find host root under $out"
 debug "host root: $hostroot"
 
-# No crawl, even a cancelled one, may leave .delayed temporaries (#107, #483).
-info "checking for leftover .delayed files"
-leftovers=$(find "$out" -name '*.delayed' 2>/dev/null | head -5)
+# No crawl, even a cancelled one, may leave engine temporaries: .delayed (#107,
+# #483), or the .z/.u content-coding temps (#557).
+info "checking for leftover engine temporaries"
+leftovers=$(find "$out" \( -name '*.delayed' -o -name '*.z' -o -name '*.u' \) 2>/dev/null | head -5)
 if test -z "$leftovers"; then result "OK"; else
     result "leftover: $leftovers"
     exit 1
@@ -436,6 +438,17 @@ while test "$i" -lt "${#audit[@]}"; do
             exit 1
         fi
         ;;
+    --file-mode)
+        path="${audit[$((i + 1))]}"
+        i=$((i + 2))
+        mode=$(stat -c '%a' "${hostroot}/${path}" 2>/dev/null ||
+            stat -f '%Lp' "${hostroot}/${path}" 2>/dev/null)
+        info "checking ${path} mode ${mode:-none} is ${audit[$i]}"
+        if test "$mode" = "${audit[$i]}"; then result "OK"; else
+            result "wrong mode"
+            exit 1
+        fi
+        ;;
     esac
     i=$((i + 1))
 done

tests/local-server.py

@@ -14,6 +14,7 @@ stdlib only (http.server + ssl) -- no new build or runtime dependency.
 """
 
 import argparse
+import base64
 import gzip
 import hashlib
 import os
@@ -633,6 +634,149 @@ class Handler(SimpleHTTPRequestHandler):
             extra_headers=[("Content-Encoding", "gzip")],
         )
 
+    # --- content codings ---------------------------------------------------
+    # Canned br/zstd bodies (no brotli/zstd module in the stdlib): both decode
+    # to CODEC_BODY. Regenerate with the brotli/zstd CLIs over that string.
+    CODEC_BODY = (
+        b"<html><head><title>codec</title></head>"
+        b"<body><p>coded body</p></body></html>"
+    )
+    CODEC_BR = base64.b64decode(
+        "G0sAAAQccqSBBfJlUvOccsDeitqC9CbHwENWiptQj5aExP0mBjjVgy2DF17olLzLo2T2Eg=="
+    )
+    CODEC_ZSTD = base64.b64decode(
+        "KLUv/SBMFQIAFAM8aHRtbD48aGVhZD48dGl0bGU+Y29kZWM8LzwvYm9keT48"
+        "cGQgPC9wPjwvL2h0bWw+BQA7p8QMDNQ1PgcWhjkG"
+    )
+
+    def route_codec_index(self):
+        self.send_html(
+            '\t<a href="br.html">br</a>\n'
+            '\t<a href="zstd.html">zstd</a>\n'
+            '\t<a href="junk.html">junk</a>\n'
+            '\t<a href="bad.html">bad</a>\n'
+            '\t<a href="bin.dat">bin</a>\n'
+            '\t<a href="ae.html">ae</a>\n'
+        )
+
+    def route_codec_br(self):
+        self.send_raw(
+            self.CODEC_BR, "text/html", extra_headers=[("Content-Encoding", "br")]
+        )
+
+    def route_codec_zstd(self):
+        self.send_raw(
+            self.CODEC_ZSTD, "text/html", extra_headers=[("Content-Encoding", "zstd")]
+        )
+
+    # Junk token on a plain body: the page must survive (broken servers do this)
+    def route_codec_junk(self):
+        self.send_raw(
+            b"<html><body><p>junk coding</p></body></html>",
+            "text/html",
+            extra_headers=[("Content-Encoding", "utf-8")],
+        )
+
+    # A real coding we have no decoder for: the fetch must fail rather than
+    # save the coded bytes as the page.
+    def route_codec_bad(self):
+        self.send_raw(
+            b"<html><body><p>never decoded</p></body></html>",
+            "text/html",
+            extra_headers=[("Content-Encoding", "compress")],
+        )
+
+    # Same, on a non-HTML body: this takes the direct-to-disk (is_write) branch,
+    # a different discard path than the in-memory bad.html above.
+    def route_codec_bin(self):
+        self.send_raw(
+            b"\x00\x01\x02 CODED-BINARY-MUST-NOT-LAND \xff\xfe" * 8,
+            "application/octet-stream",
+            extra_headers=[("Content-Encoding", "compress")],
+        )
+
+    # --- coded re-fetch that fails to decode (#557) -------------------------
+    # Pass 1 mirrors each file from a valid gzip body; pass 2 (--update) serves
+    # a body that cannot be decoded. The previously-mirrored copy must survive.
+    # fresh.html is the control: its pass-2 body decodes, so it must be updated.
+    UPCODEC_SEEN = {}
+
+    def upcodec_pass(self):
+        """1 on the first body fetch of this path, 2 on the next ones. HEADs
+        don't count, so a stray one can't shift which pass gets the bad body."""
+        if self.command == "HEAD":
+            return 1
+        seen = Handler.UPCODEC_SEEN.get(self.path, 0) + 1
+        Handler.UPCODEC_SEEN[self.path] = seen
+        return seen
+
+    @staticmethod
+    def gzipped(body):
+        return gzip.compress(body)
+
+    @staticmethod
+    def bad_gzip(body):
+        """A gzip stream whose deflate payload is mangled: inflate fails partway
+        through, after some plausible output has already been produced."""
+        raw = bytearray(gzip.compress(body))
+        raw[20:40] = b"\xff" * 20
+        return bytes(raw[:-4])
+
+    def send_coded(self, body, content_type, coding="gzip"):
+        self.send_raw(body, content_type, extra_headers=[("Content-Encoding", coding)])
+
+    def route_upcodec_index(self):
+        self.send_html(
+            '\t<a href="mem.html">mem</a>\n'
+            '\t<a href="disk.bin">disk</a>\n'
+            '\t<a href="unsup.html">unsup</a>\n'
+            '\t<a href="fresh.html">fresh</a>\n'
+            '\t<a href="freshdisk.bin">freshdisk</a>\n'
+        )
+
+    MEM_V1 = b"<html><body><p>MIRRORED-MEM-V1</p></body></html>"
+    DISK_V1 = b"MIRRORED-DISK-V1\n" + b"\x00\x01\x02\xff" * 8192
+    UNSUP_V1 = b"<html><body><p>MIRRORED-UNSUP-V1</p></body></html>"
+
+    def route_upcodec_mem(self):
+        if self.upcodec_pass() == 1:
+            self.send_coded(self.gzipped(self.MEM_V1), "text/html")
+        else:
+            self.send_coded(self.bad_gzip(self.MEM_V1), "text/html")
+
+    def route_upcodec_disk(self):
+        if self.upcodec_pass() == 1:
+            self.send_coded(self.gzipped(self.DISK_V1), "application/octet-stream")
+        else:
+            self.send_coded(self.bad_gzip(self.DISK_V1), "application/octet-stream")
+
+    # Pass 2 switches to a coding we have no decoder for.
+    def route_upcodec_unsup(self):
+        if self.upcodec_pass() == 1:
+            self.send_coded(self.gzipped(self.UNSUP_V1), "text/html")
+        else:
+            self.send_coded(self.UNSUP_V1, "text/html", coding="compress")
+
+    def route_upcodec_fresh(self):
+        pass1 = self.upcodec_pass() == 1
+        body = b"<html><body><p>FRESH-V%d</p></body></html>" % (1 if pass1 else 2)
+        self.send_coded(self.gzipped(body), "text/html")
+
+    # Same, direct-to-disk: the update pass decodes, so the temp is renamed over
+    # an existing mirror file.
+    def route_upcodec_freshdisk(self):
+        pass1 = self.upcodec_pass() == 1
+        body = b"FRESHDISK-V%d\n" % (1 if pass1 else 2) + b"\x03\x02\x01\xfe" * 8192
+        self.send_coded(self.gzipped(body), "application/octet-stream")
+
+    # Echo what httrack advertised, so a crawl can assert the header.
+    def route_codec_ae(self):
+        self.send_raw(
+            b"<html><body><p>AE=%s</p></body></html>"
+            % self.headers.get("Accept-Encoding", "").encode(),
+            "text/html",
+        )
+
     # --- MIME-type exclusion abort (issue #58) -----------------------------
     # A -mime:application/pdf filter must abort the transfer once the header
     # arrives, not download the whole body and discard it.
@@ -1315,6 +1459,19 @@ class Handler(SimpleHTTPRequestHandler):
         "/gated/index.php": route_gated_index,
         "/gated/secret.php": route_gated_secret,
         "/robots.txt": route_robots,
+        "/codec/index.html": route_codec_index,
+        "/codec/br.html": route_codec_br,
+        "/codec/zstd.html": route_codec_zstd,
+        "/codec/junk.html": route_codec_junk,
+        "/codec/bad.html": route_codec_bad,
+        "/codec/bin.dat": route_codec_bin,
+        "/codec/ae.html": route_codec_ae,
+        "/upcodec/index.html": route_upcodec_index,
+        "/upcodec/mem.html": route_upcodec_mem,
+        "/upcodec/disk.bin": route_upcodec_disk,
+        "/upcodec/unsup.html": route_upcodec_unsup,
+        "/upcodec/fresh.html": route_upcodec_fresh,
+        "/upcodec/freshdisk.bin": route_upcodec_freshdisk,
         "/types/index.html": route_types_index,
         "/types/control.php": route_types,
         "/types/photo.png": route_types,

tests/socks5-server.py

@@ -0,0 +1,228 @@
+#!/usr/bin/env python3
+"""Local SOCKS5 proxy (RFC 1928/1929) + TLS and plain HTTP origins for #563.
+
+Logs the auth method, any user/pass, and the CONNECT ATYP + literal domain, so
+the test proves httrack sent a hostname (remote DNS) and negotiated auth.
+Modes (argv[3]): ok | refuse (REP=5) | truncate (partial reply, must not hang).
+Usage: socks5-server.py <cert.pem> <logdir> [mode]
+Prints "TLS <port>", "HTTP <port>", "SOCKS <port>", "ready" on stdout.
+"""
+import http.server
+import os
+import socket
+import socketserver
+import ssl
+import struct
+import sys
+import threading
+
+# The one name the proxy answers for; a .invalid TLD never resolves (RFC 6761),
+# so a locally-resolving client could not reach us -- success proves remote DNS.
+REMOTE_HOST = b"socks-origin.invalid"
+# index links the subpages so an -r3 crawl reuses one keep-alive socket
+LINKS = "".join('<a href="/p%d.html">%d</a>' % (i, i) for i in range(1, 6))
+ORIGIN_BODY = ("<html><body>ORIGIN-PAGE-563 " + LINKS + "</body></html>").encode()
+SOCKS_LOG = "socks.log"
+ORIGIN_LOG = "origin-headers.log"
+
+
+def make_origin(logdir):
+    class Origin(http.server.BaseHTTPRequestHandler):
+        # HTTP/1.1 + a max>1 advertisement lets httrack keep the socket alive
+        protocol_version = "HTTP/1.1"
+
+        def do_GET(self):
+            with open(os.path.join(logdir, ORIGIN_LOG), "a") as handle:
+                handle.write(
+                    "REQUEST %s %s %s\n"
+                    % (self.command, self.path, self.request_version)
+                )
+                for key in self.headers.keys():
+                    handle.write(key + ": " + self.headers[key] + "\n")
+            if "p" in self.path and ".html" in self.path:
+                body = (
+                    b"<html><body>SUBPAGE-563 " + self.path.encode() + b"</body></html>"
+                )
+            else:
+                body = ORIGIN_BODY
+            self.send_response(200)
+            self.send_header("Content-Type", "text/html")
+            self.send_header("Content-Length", str(len(body)))
+            self.send_header("Keep-Alive", "timeout=15, max=100")
+            self.send_header("Connection", "keep-alive")
+            self.end_headers()
+            self.wfile.write(body)
+
+        def log_message(self, *args):
+            pass
+
+    return Origin
+
+
+class ThreadingTCPServer(socketserver.ThreadingTCPServer):
+    allow_reuse_address = True
+    daemon_threads = True
+
+
+def start_origin(logdir, certfile=None):
+    httpd = ThreadingTCPServer(("127.0.0.1", 0), make_origin(logdir))
+    if certfile is not None:
+        ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+        ctx.load_cert_chain(certfile)
+        httpd.socket = ctx.wrap_socket(httpd.socket, server_side=True)
+    port = httpd.socket.getsockname()[1]
+    threading.Thread(target=httpd.serve_forever, daemon=True).start()
+    return port
+
+
+def recvn(conn, n):
+    buf = b""
+    while len(buf) < n:
+        chunk = conn.recv(n - len(buf))
+        if not chunk:
+            raise OSError("short read")
+        buf += chunk
+    return buf
+
+
+def pipe(src, dst):
+    try:
+        while True:
+            data = src.recv(65536)
+            if not data:
+                break
+            dst.sendall(data)
+    except OSError:
+        pass
+    finally:
+        for sock in (src, dst):
+            try:
+                sock.shutdown(socket.SHUT_RDWR)
+            except OSError:
+                pass
+
+
+def log(logdir, line):
+    with open(os.path.join(logdir, SOCKS_LOG), "a") as handle:
+        handle.write(line + "\n")
+
+
+def negotiate_auth(conn, logdir):
+    """RFC 1928 greeting + RFC 1929 sub-negotiation. Returns True to proceed."""
+    ver, nmethods = recvn(conn, 2)
+    if ver != 0x05:
+        return False
+    methods = recvn(conn, nmethods)
+    if 0x02 in methods:  # prefer user/pass so the auth test exercises RFC 1929
+        conn.sendall(b"\x05\x02")
+        (subver,) = recvn(conn, 1)
+        (ulen,) = recvn(conn, 1)
+        uname = recvn(conn, ulen)
+        (plen,) = recvn(conn, 1)
+        passwd = recvn(conn, plen)
+        log(logdir, "METHOD userpass")
+        log(logdir, "AUTH %s %s" % (uname.decode(), passwd.decode()))
+        conn.sendall(b"\x01\x00")  # RFC 1929 success
+    elif 0x00 in methods:
+        conn.sendall(b"\x05\x00")
+        log(logdir, "METHOD noauth")
+    else:
+        conn.sendall(b"\x05\xff")  # no acceptable method
+        return False
+    return True
+
+
+def read_request(conn, logdir):
+    """RFC 1928 CONNECT. Logs CMD, ATYP, domain/addr, port. Returns dest port."""
+    ver, cmd, _rsv, atyp = recvn(conn, 4)
+    log(logdir, "CMD %d" % cmd)
+    if atyp == 0x01:
+        addr = socket.inet_ntoa(recvn(conn, 4))
+        log(logdir, "ATYP ipv4 %s" % addr)
+    elif atyp == 0x03:
+        (dlen,) = recvn(conn, 1)
+        domain = recvn(conn, dlen)
+        log(logdir, "ATYP domain %s" % domain.decode())
+    elif atyp == 0x04:
+        recvn(conn, 16)
+        log(logdir, "ATYP ipv6")
+        domain = b""
+    else:
+        return None, None
+    (port,) = struct.unpack(">H", recvn(conn, 2))
+    log(logdir, "PORT %d" % port)
+    name = domain if atyp == 0x03 else b""
+    return name, port
+
+
+def reply(conn, rep):
+    conn.sendall(bytes([0x05, rep, 0x00, 0x01]) + b"\x00\x00\x00\x00" + b"\x00\x00")
+
+
+def handle_socks(conn, logdir, mode):
+    try:
+        if not negotiate_auth(conn, logdir):
+            conn.close()
+            return
+        if mode == "truncate":
+            # one byte of the 10-byte reply, then hold the socket: the client
+            # must bound this handshake read and give up, not hang.
+            conn.sendall(b"\x05")
+            threading.Event().wait()
+            return
+        name, port = read_request(conn, logdir)
+        if mode == "refuse" or name != REMOTE_HOST or port is None:
+            reply(conn, 0x05)  # connection refused
+            conn.close()
+            return
+        try:
+            upstream = socket.create_connection(("127.0.0.1", port))
+        except OSError:
+            reply(conn, 0x05)
+            conn.close()
+            return
+        reply(conn, 0x00)  # succeeded
+        threading.Thread(target=pipe, args=(conn, upstream), daemon=True).start()
+        pipe(upstream, conn)
+    except OSError:
+        try:
+            conn.close()
+        except OSError:
+            pass
+
+
+def start_socks(logdir, mode):
+    srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    srv.bind(("127.0.0.1", 0))
+    srv.listen(16)
+    port = srv.getsockname()[1]
+
+    def serve():
+        while True:
+            conn, _ = srv.accept()
+            threading.Thread(
+                target=handle_socks, args=(conn, logdir, mode), daemon=True
+            ).start()
+
+    threading.Thread(target=serve, daemon=True).start()
+    return port
+
+
+def main():
+    certfile, logdir = sys.argv[1], sys.argv[2]
+    mode = sys.argv[3] if len(sys.argv) > 3 else "ok"
+    for name in (SOCKS_LOG, ORIGIN_LOG):
+        open(os.path.join(logdir, name), "w").close()
+    tls_port = start_origin(logdir, certfile)
+    http_port = start_origin(logdir, None)
+    socks_port = start_socks(logdir, mode)
+    print("TLS %d" % tls_port, flush=True)
+    print("HTTP %d" % http_port, flush=True)
+    print("SOCKS %d" % socks_port, flush=True)
+    print("ready", flush=True)
+    threading.Event().wait()
+
+
+if __name__ == "__main__":
+    main()