Modernize the default User-Agent (#449)

The default UA was "Mozilla/4.5 (compatible; HTTrack 3.0x; Windows 98)",
a 25-year-old string naming a dead OS and trivially fingerprinted. Replace
it with an honest crawler UA carrying the HTTrack token and a reference URL:
"Mozilla/5.0 (compatible; HTTrack/3.x; +https://www.httrack.com/)".

Both the engine default (hts_create_opt) and the webhttrack mini-server
config default now share one HTS_DEFAULT_USER_AGENT macro, built from
HTTRACK_AFF_VERSION so the version token tracks releases without going stale.

Closes #449

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

src/htsglobal.h

@@ -229,6 +229,10 @@ Please visit our Website: http://www.httrack.com
 #define HTS_DEFAULT_FOOTER                                                     \
   "<!-- Mirrored from %s%s by HTTrack Website Copier/" HTTRACK_AFF_VERSION     \
   " " HTTRACK_AFF_AUTHORS ", %s -->"
+/* Honest crawler User-Agent; no fake OS/browser to go stale. */
+#define HTS_DEFAULT_USER_AGENT                                                 \
+  "Mozilla/5.0 (compatible; HTTrack/" HTTRACK_AFF_VERSION                      \
+  "; +https://www.httrack.com/)"
 #define HTTRACK_WEB "http://www.httrack.com"
 #define HTS_UPDATE_WEBSITE                                                     \
   "http://www.httrack.com/"                                                    \

src/htslib.c

@@ -563,6 +563,39 @@ const char *hts_mime[][2] = {
   {"", ""}
 };
 
+/* Modern web formats (post-2010), kept in their own table: appending to the
+   legacy hts_mime[] above makes clang-format reflow its whole initializer.
+   Scanned after hts_mime[], so it never shadows a legacy mapping. */
+static const char *hts_mime_modern[][2] = {
+    {"image/webp", "webp"},
+    {"image/avif", "avif"},
+    {"image/heic", "heic"},
+    {"font/woff", "woff"},
+    {"font/woff2", "woff2"},
+    {"font/ttf", "ttf"},
+    {"font/otf", "otf"},
+    {"application/json", "json"},
+    {"application/ld+json", "jsonld"},
+    {"application/manifest+json", "webmanifest"},
+    {"application/wasm", "wasm"},
+    {"text/javascript", "js"},
+    {"text/javascript", "mjs"},
+    {"text/markdown", "md"},
+    {"video/mp4", "mp4"},
+    {"video/webm", "webm"},
+    {"video/ogg", "ogv"},
+    {"video/mp2t", "ts"},
+    {"audio/mp4", "m4a"},
+    {"audio/aac", "aac"},
+    {"audio/ogg", "oga"},
+    {"audio/opus", "opus"},
+    {"audio/flac", "flac"},
+    {"audio/webm", "weba"},
+    {"application/x-7z-compressed", "7z"},
+    {"application/x-rar-compressed", "rar"},
+    {"application/zstd", "zst"},
+    {"", ""}};
+
 // Reserved (RFC2396)
 #define CIS(c,ch) ( ((unsigned char)(c)) == (ch) )
 #define CHAR_RESERVED(c)  ( CIS(c,';') \
@@ -4308,6 +4341,20 @@ void guess_httptype(httrackp * opt, char *s, const char *fil) {
   (void) get_httptype_sized(opt, s, HTS_MIMETYPE_SIZE, fil, 1);
 }
 
+// first match in a NUL-terminated {mime,ext} table. key selects the lookup
+// column (0=mime, 1=ext); returns the other column, or NULL if no row matches
+// (a "*" partner means the row carries no value).
+static const char *hts_mime_lookup(const char *(*table)[2], int key,
+                                   const char *needle) {
+  int j;
+
+  for (j = 0; strnotempty(table[j][1]); j++) {
+    if (strfield2(table[j][key], needle) && table[j][!key][0] != '*')
+      return table[j][!key];
+  }
+  return NULL;
+}
+
 // write the mime type for fil into s (capacity ssize)
 // flag: 1 to always return a type (the "application/..." / octet-stream
 // fallback) returns 1 if a type was written to s, 0 otherwise
@@ -4331,17 +4378,15 @@ HTSEXT_API hts_boolean get_httptype_sized(httrackp *opt, char *s, size_t ssize,
     while ((a > fil) && (*a != '.') && (*a != '/'))
       a--;
     if (a >= fil && *a == '.' && strlen(a) < 32) {
-      int j = 0;
+      const char *mime;
 
       a++;
-      while(strnotempty(hts_mime[j][1])) {
-        if (strfield2(hts_mime[j][1], a)) {
-          if (hts_mime[j][0][0] != '*') { // a match exists
-            strlcpybuff(s, hts_mime[j][0], ssize);
-            return 1;
-          }
-        }
-        j++;
+      mime = hts_mime_lookup(hts_mime, 1, a);
+      if (mime == NULL)
+        mime = hts_mime_lookup(hts_mime_modern, 1, a);
+      if (mime != NULL) {
+        strlcpybuff(s, mime, ssize);
+        return 1;
       }
 
       if (flag) {
@@ -4476,18 +4521,16 @@ int get_userhttptype(httrackp * opt, char *s, const char *fil) {
 // returns 1 if an extension was found (and written to s), 0 otherwise
 int give_mimext(char *s, size_t ssize, const char *st) {
   int ok = 0;
-  int j = 0;
+  const char *ext;
 
   st = hts_effective_mime(st); /* no declared type: derive an html ext */
   s[0] = '\0';
-  while((!ok) && (strnotempty(hts_mime[j][1]))) {
-    if (strfield2(hts_mime[j][0], st)) {
-      if (hts_mime[j][1][0] != '*') { // a match exists
-        strlcpybuff(s, hts_mime[j][1], ssize);
-        ok = 1;
-      }
-    }
-    j++;
+  ext = hts_mime_lookup(hts_mime, 0, st);
+  if (ext == NULL)
+    ext = hts_mime_lookup(hts_mime_modern, 0, st);
+  if (ext != NULL) {
+    strlcpybuff(s, ext, ssize);
+    ok = 1;
   }
   // wrap "x" mimetypes, such as:
   // application/x-mp3
@@ -6005,8 +6048,7 @@ HTSEXT_API httrackp *hts_create_opt(void) {
   opt->shell = HTS_FALSE;
   opt->proxy.active = 0;        // pas de proxy
   opt->user_agent_send = HTS_TRUE;
-  StringCopy(opt->user_agent,
-             "Mozilla/4.5 (compatible; HTTrack 3.0x; Windows 98)");
+  StringCopy(opt->user_agent, HTS_DEFAULT_USER_AGENT);
   StringCopy(opt->referer, "");
   StringCopy(opt->from, "");
   opt->savename_83 = HTS_SAVENAME_83_LONG; // long names by default

src/htsselftest.c

@@ -239,6 +239,14 @@ static void basic_selftests(void) {
     assertf(strcmp(ext, "html") == 0);
     assertf(give_mimext(ext, sizeof(ext), "no/such-mime-type") == 0);
     assertf(ext[0] == '\0');
+    // modern web formats -> extension. Avoid MIME types the
+    // application/<=4-char-subtype fallback could fabricate without a row.
+    assertf(give_mimext(ext, sizeof(ext), "image/webp") == 1);
+    assertf(strcmp(ext, "webp") == 0);
+    assertf(give_mimext(ext, sizeof(ext), "application/manifest+json") == 1);
+    assertf(strcmp(ext, "webmanifest") == 0);
+    assertf(give_mimext(ext, sizeof(ext), "font/woff2") == 1);
+    assertf(strcmp(ext, "woff2") == 0);
   }
   // convtolower(): lower-cases into the caller buffer (bounded by its size).
   {
@@ -293,6 +301,16 @@ static void basic_selftests(void) {
     assertf(get_httptype_sized(opt, r.contenttype, sizeof(r.contenttype),
                                "x.gif", 0) == 1);
     assertf(strcmp(r.contenttype, "image/gif") == 0);
+    // modern extensions map back to their MIME type
+    assertf(get_httptype_sized(opt, r.contenttype, sizeof(r.contenttype),
+                               "x.webp", 0) == 1);
+    assertf(strcmp(r.contenttype, "image/webp") == 0);
+    assertf(get_httptype_sized(opt, r.contenttype, sizeof(r.contenttype),
+                               "app.wasm", 0) == 1);
+    assertf(strcmp(r.contenttype, "application/wasm") == 0);
+    assertf(get_httptype_sized(opt, r.contenttype, sizeof(r.contenttype),
+                               "mod.mjs", 0) == 1);
+    assertf(strcmp(r.contenttype, "text/javascript") == 0);
     // no extension and flag==0: nothing written, returns 0
     assertf(get_httptype_sized(opt, r.contenttype, sizeof(r.contenttype),
                                "noextfile", 0) == 0);
@@ -1284,6 +1302,21 @@ static int st_urlhack(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+/* Default User-Agent: honest HTTrack token, no resurrected Windows 98. */
+static int st_useragent(httrackp *opt, int argc, char **argv) {
+  const char *ua = StringBuff(opt->user_agent);
+  (void) argc;
+  (void) argv;
+  assertf(ua != NULL);
+  assertf(strcmp(ua, HTS_DEFAULT_USER_AGENT) == 0);
+  /* Macro-independent teeth: token, self-id URL, no Mozilla/4.x. */
+  assertf(strstr(ua, "HTTrack/") != NULL);
+  assertf(strstr(ua, "+https://www.httrack.com/") != NULL);
+  assertf(strstr(ua, "Mozilla/4.") == NULL);
+  printf("useragent self-test OK: %s\n", ua);
+  return 0;
+}
+
 /* ------------------------------------------------------------ */
 /* Registry: name -> handler, with a usage hint and a one-line description. */
 /* ------------------------------------------------------------ */
@@ -1330,6 +1363,7 @@ static const struct selftest_entry {
      st_cache_writefail},
     {"dns", "", "DNS resolver/cache self-test", st_dns},
     {"cookies", "", "cookie request-header self-test", st_cookies},
+    {"useragent", "", "default User-Agent self-test", st_useragent},
 };
 
 static void list_selftests(void) {

src/htsserver.c

@@ -358,12 +358,12 @@ int smallserver(T_SOC soc, char *url, char *method, char *data, char *path) {
       {NULL, 0}
     };
     initStrElt initStr[] = {
-      {"user", "Mozilla/4.5 (compatible; HTTrack 3.0x; Windows 98)"},
-      {"footer",
-       "<!-- Mirrored from %s%s by HTTrack Website Copier/3.x [XR&CO'2014], %s -->"},
-      {"url2", "+*.png +*.gif +*.jpg +*.jpeg +*.css +*.js -ad.doubleclick.net/*"},
-      {NULL, NULL}
-    };
+        {"user", HTS_DEFAULT_USER_AGENT},
+        {"footer", "<!-- Mirrored from %s%s by HTTrack Website Copier/3.x "
+                   "[XR&CO'2014], %s -->"},
+        {"url2",
+         "+*.png +*.gif +*.jpg +*.jpeg +*.css +*.js -ad.doubleclick.net/*"},
+        {NULL, NULL}};
     int i = 0;
 
     for(i = 0; initInt[i].name; i++) {

tests/01_engine-useragent.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# Default User-Agent (#449): honest HTTrack token, no Windows 98 relic.
+httrack -O /dev/null -#test=useragent run | grep -q "useragent self-test OK"

tests/Makefile.am

@@ -50,6 +50,7 @@ TESTS = \
 	01_engine-stripquery.test \
 	01_engine-strsafe.test \
 	01_engine-urlhack.test \
+	01_engine-useragent.test \
 	02_manpage-regen.test \
 	02_update-cache.test \
 	10_crawl-simple.test \