1 /* Collect URLs from HTML source.
2 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
3 2007, 2008 Free Software Foundation, Inc.
5 This file is part of GNU Wget.
7 GNU Wget is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 GNU Wget is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Wget. If not, see <http://www.gnu.org/licenses/>.
20 Additional permission under GNU GPL version 3 section 7
22 If you modify this program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a
24 modified version of that library), containing parts covered by the
25 terms of the OpenSSL or SSLeay licenses, the Free Software Foundation
26 grants you additional permission to convey the resulting work.
27 Corresponding Source for a non-source form of such a combination
28 shall include the source code for the parts of OpenSSL used as well
29 as that of the covered work. */
39 #include "html-parse.h"
48 typedef void (*tag_handler_t) (int, struct taginfo *, struct map_context *);
50 #define DECLARE_TAG_HANDLER(fun) \
51 static void fun (int, struct taginfo *, struct map_context *)
53 DECLARE_TAG_HANDLER (tag_find_urls);
54 DECLARE_TAG_HANDLER (tag_handle_base);
55 DECLARE_TAG_HANDLER (tag_handle_form);
56 DECLARE_TAG_HANDLER (tag_handle_link);
57 DECLARE_TAG_HANDLER (tag_handle_meta);
84 /* The list of known tags and functions used for handling them. Most
85 tags are simply harvested for URLs. */
86 static struct known_tag {
89 tag_handler_t handler;
91 { TAG_A, "a", tag_find_urls },
92 { TAG_APPLET, "applet", tag_find_urls },
93 { TAG_AREA, "area", tag_find_urls },
94 { TAG_BASE, "base", tag_handle_base },
95 { TAG_BGSOUND, "bgsound", tag_find_urls },
96 { TAG_BODY, "body", tag_find_urls },
97 { TAG_EMBED, "embed", tag_find_urls },
98 { TAG_FIG, "fig", tag_find_urls },
99 { TAG_FORM, "form", tag_handle_form },
100 { TAG_FRAME, "frame", tag_find_urls },
101 { TAG_IFRAME, "iframe", tag_find_urls },
102 { TAG_IMG, "img", tag_find_urls },
103 { TAG_INPUT, "input", tag_find_urls },
104 { TAG_LAYER, "layer", tag_find_urls },
105 { TAG_LINK, "link", tag_handle_link },
106 { TAG_META, "meta", tag_handle_meta },
107 { TAG_OBJECT, "object", tag_find_urls },
108 { TAG_OVERLAY, "overlay", tag_find_urls },
109 { TAG_SCRIPT, "script", tag_find_urls },
110 { TAG_TABLE, "table", tag_find_urls },
111 { TAG_TD, "td", tag_find_urls },
112 { TAG_TH, "th", tag_find_urls }
115 /* tag_url_attributes documents which attributes of which tags contain
116 URLs to harvest. It is used by tag_find_urls. */
118 /* Defines for the FLAGS. */
120 /* The link is "inline", i.e. needs to be retrieved for this document
121 to be correctly rendered. Inline links include inlined images,
122 stylesheets, children frames, etc. */
123 #define ATTR_INLINE 1
125 /* The link is expected to yield HTML contents. It's important not to
126 try to follow HTML obtained by following e.g. <img src="...">
127 regardless of content-type. Doing this causes infinite loops for
128 "images" that return non-404 error pages with links to the same
132 /* For tags handled by tag_find_urls: attributes that contain URLs to
136 const char *attr_name;
138 } tag_url_attributes[] = {
139 { TAG_A, "href", ATTR_HTML },
140 { TAG_APPLET, "code", ATTR_INLINE },
141 { TAG_AREA, "href", ATTR_HTML },
142 { TAG_BGSOUND, "src", ATTR_INLINE },
143 { TAG_BODY, "background", ATTR_INLINE },
144 { TAG_EMBED, "href", ATTR_HTML },
145 { TAG_EMBED, "src", ATTR_INLINE | ATTR_HTML },
146 { TAG_FIG, "src", ATTR_INLINE },
147 { TAG_FRAME, "src", ATTR_INLINE | ATTR_HTML },
148 { TAG_IFRAME, "src", ATTR_INLINE | ATTR_HTML },
149 { TAG_IMG, "href", ATTR_INLINE },
150 { TAG_IMG, "lowsrc", ATTR_INLINE },
151 { TAG_IMG, "src", ATTR_INLINE },
152 { TAG_INPUT, "src", ATTR_INLINE },
153 { TAG_LAYER, "src", ATTR_INLINE | ATTR_HTML },
154 { TAG_OBJECT, "data", ATTR_INLINE },
155 { TAG_OVERLAY, "src", ATTR_INLINE | ATTR_HTML },
156 { TAG_SCRIPT, "src", ATTR_INLINE },
157 { TAG_TABLE, "background", ATTR_INLINE },
158 { TAG_TD, "background", ATTR_INLINE },
159 { TAG_TH, "background", ATTR_INLINE }
162 /* The lists of interesting tags and attributes are built dynamically,
163 from the information above. However, some places in the code refer
164 to the attributes not mentioned here. We add them manually. */
165 static const char *additional_attributes[] = {
166 "rel", /* used by tag_handle_link */
167 "http-equiv", /* used by tag_handle_meta */
168 "name", /* used by tag_handle_meta */
169 "content", /* used by tag_handle_meta */
170 "action", /* used by tag_handle_form */
171 "style" /* used by check_style_attr */
174 static struct hash_table *interesting_tags;
175 static struct hash_table *interesting_attributes;
177 /* Will contains the (last) charset found in 'http-equiv=content-type'
179 static char *meta_charset;
182 init_interesting (void)
184 /* Init the variables interesting_tags and interesting_attributes
185 that are used by the HTML parser to know which tags and
186 attributes we're interested in. We initialize this only once,
187 for performance reasons.
189 Here we also make sure that what we put in interesting_tags
190 matches the user's preferences as specified through --ignore-tags
191 and --follow-tags. */
194 interesting_tags = make_nocase_string_hash_table (countof (known_tags));
196 /* First, add all the tags we know hot to handle, mapped to their
197 respective entries in known_tags. */
198 for (i = 0; i < countof (known_tags); i++)
199 hash_table_put (interesting_tags, known_tags[i].name, known_tags + i);
201 /* Then remove the tags ignored through --ignore-tags. */
205 for (ignored = opt.ignore_tags; *ignored; ignored++)
206 hash_table_remove (interesting_tags, *ignored);
209 /* If --follow-tags is specified, use only those tags. */
212 /* Create a new table intersecting --follow-tags and known_tags,
213 and use it as interesting_tags. */
214 struct hash_table *intersect = make_nocase_string_hash_table (0);
216 for (followed = opt.follow_tags; *followed; followed++)
218 struct known_tag *t = hash_table_get (interesting_tags, *followed);
220 continue; /* ignore unknown --follow-tags entries. */
221 hash_table_put (intersect, *followed, t);
223 hash_table_destroy (interesting_tags);
224 interesting_tags = intersect;
227 /* Add the attributes we care about. */
228 interesting_attributes = make_nocase_string_hash_table (10);
229 for (i = 0; i < countof (additional_attributes); i++)
230 hash_table_put (interesting_attributes, additional_attributes[i], "1");
231 for (i = 0; i < countof (tag_url_attributes); i++)
232 hash_table_put (interesting_attributes,
233 tag_url_attributes[i].attr_name, "1");
236 /* Find the value of attribute named NAME in the taginfo TAG. If the
237 attribute is not present, return NULL. If ATTRIND is non-NULL, the
238 index of the attribute in TAG will be stored there. */
241 find_attr (struct taginfo *tag, const char *name, int *attrind)
244 for (i = 0; i < tag->nattrs; i++)
245 if (!strcasecmp (tag->attrs[i].name, name))
249 return tag->attrs[i].value;
254 /* used for calls to append_url */
255 #define ATTR_POS(tag, attrind, ctx) \
256 (tag->attrs[attrind].value_raw_beginning - ctx->text)
257 #define ATTR_SIZE(tag, attrind) \
258 (tag->attrs[attrind].value_raw_size)
260 /* Append LINK_URI to the urlpos structure that is being built.
262 LINK_URI will be merged with the current document base.
266 append_url (const char *link_uri, int position, int size,
267 struct map_context *ctx)
269 int link_has_scheme = url_has_scheme (link_uri);
270 struct urlpos *newel;
271 const char *base = ctx->base ? ctx->base : ctx->parent_base;
276 DEBUGP (("%s: no base, merge will use \"%s\".\n",
277 ctx->document_file, link_uri));
279 if (!link_has_scheme)
281 /* Base URL is unavailable, and the link does not have a
282 location attached to it -- we have to give up. Since
283 this can only happen when using `--force-html -i', print
285 logprintf (LOG_NOTQUIET,
286 _("%s: Cannot resolve incomplete link %s.\n"),
287 ctx->document_file, link_uri);
291 url = url_parse (link_uri, NULL, NULL, false);
294 DEBUGP (("%s: link \"%s\" doesn't parse.\n",
295 ctx->document_file, link_uri));
301 /* Merge BASE with LINK_URI, but also make sure the result is
302 canonicalized, i.e. that "../" have been resolved.
303 (parse_url will do that for us.) */
305 char *complete_uri = uri_merge (base, link_uri);
307 DEBUGP (("%s: merge(%s, %s) -> %s\n",
308 quotearg_n_style (0, escape_quoting_style, ctx->document_file),
310 quote_n (2, link_uri),
311 quotearg_n_style (3, escape_quoting_style, complete_uri)));
313 url = url_parse (complete_uri, NULL, NULL, false);
316 DEBUGP (("%s: merged link \"%s\" doesn't parse.\n",
317 ctx->document_file, complete_uri));
318 xfree (complete_uri);
321 xfree (complete_uri);
324 DEBUGP (("appending %s to urlpos.\n", quote (url->url)));
326 newel = xnew0 (struct urlpos);
328 newel->pos = position;
331 /* A URL is relative if the host is not named, and the name does not
333 if (!link_has_scheme && *link_uri != '/')
334 newel->link_relative_p = 1;
335 else if (link_has_scheme)
336 newel->link_complete_p = 1;
340 ctx->tail->next = newel;
344 ctx->tail = ctx->head = newel;
350 check_style_attr (struct taginfo *tag, struct map_context *ctx)
353 char *style = find_attr (tag, "style", &attrind);
357 /* raw pos and raw size include the quotes, hence the +1 -2 */
358 get_urls_css (ctx, ATTR_POS(tag,attrind,ctx)+1, ATTR_SIZE(tag,attrind)-2);
361 /* All the tag_* functions are called from collect_tags_mapper, as
362 specified by KNOWN_TAGS. */
364 /* Default tag handler: collect URLs from attributes specified for
365 this tag by tag_url_attributes. */
368 tag_find_urls (int tagid, struct taginfo *tag, struct map_context *ctx)
374 for (i = 0; i < countof (tag_url_attributes); i++)
375 if (tag_url_attributes[i].tagid == tagid)
377 /* We've found the index of tag_url_attributes where the
378 attributes of our tag begin. */
382 assert (first != -1);
384 /* Loop over the "interesting" attributes of this tag. In this
385 example, it will loop over "src" and "lowsrc".
387 <img src="foo.png" lowsrc="bar.png">
389 This has to be done in the outer loop so that the attributes are
390 processed in the same order in which they appear in the page.
391 This is required when converting links. */
393 for (attrind = 0; attrind < tag->nattrs; attrind++)
395 /* Find whether TAG/ATTRIND is a combination that contains a
397 char *link = tag->attrs[attrind].value;
398 const size_t size = countof (tag_url_attributes);
400 /* If you're cringing at the inefficiency of the nested loops,
401 remember that they both iterate over a very small number of
402 items. The worst-case inner loop is for the IMG tag, which
403 has three attributes. */
404 for (i = first; i < size && tag_url_attributes[i].tagid == tagid; i++)
406 if (0 == strcasecmp (tag->attrs[attrind].name,
407 tag_url_attributes[i].attr_name))
409 struct urlpos *up = append_url (link, ATTR_POS(tag,attrind,ctx),
410 ATTR_SIZE(tag,attrind), ctx);
413 int flags = tag_url_attributes[i].flags;
414 if (flags & ATTR_INLINE)
415 up->link_inline_p = 1;
416 if (flags & ATTR_HTML)
417 up->link_expect_html = 1;
424 /* Handle the BASE tag, for <base href=...>. */
427 tag_handle_base (int tagid, struct taginfo *tag, struct map_context *ctx)
429 struct urlpos *base_urlpos;
431 char *newbase = find_attr (tag, "href", &attrind);
435 base_urlpos = append_url (newbase, ATTR_POS(tag,attrind,ctx),
436 ATTR_SIZE(tag,attrind), ctx);
439 base_urlpos->ignore_when_downloading = 1;
440 base_urlpos->link_base_p = 1;
444 if (ctx->parent_base)
445 ctx->base = uri_merge (ctx->parent_base, newbase);
447 ctx->base = xstrdup (newbase);
450 /* Mark the URL found in <form action=...> for conversion. */
453 tag_handle_form (int tagid, struct taginfo *tag, struct map_context *ctx)
456 char *action = find_attr (tag, "action", &attrind);
460 struct urlpos *up = append_url (action, ATTR_POS(tag,attrind,ctx),
461 ATTR_SIZE(tag,attrind), ctx);
463 up->ignore_when_downloading = 1;
467 /* Handle the LINK tag. It requires special handling because how its
468 links will be followed in -p mode depends on the REL attribute. */
471 tag_handle_link (int tagid, struct taginfo *tag, struct map_context *ctx)
474 char *href = find_attr (tag, "href", &attrind);
476 /* All <link href="..."> link references are external, except those
477 known not to be, such as style sheet and shortcut icon:
479 <link rel="stylesheet" href="...">
480 <link rel="shortcut icon" href="...">
484 struct urlpos *up = append_url (href, ATTR_POS(tag,attrind,ctx),
485 ATTR_SIZE(tag,attrind), ctx);
488 char *rel = find_attr (tag, "rel", NULL);
491 if (0 == strcasecmp (rel, "stylesheet"))
493 up->link_inline_p = 1;
494 up->link_expect_css = 1;
496 else if (0 == strcasecmp (rel, "shortcut icon"))
498 up->link_inline_p = 1;
502 /* The external ones usually point to HTML pages, such as
503 <link rel="next" href="..."> */
504 up->link_expect_html = 1;
509 /* Handle the META tag. This requires special handling because of the
510 refresh feature and because of robot exclusion. */
513 tag_handle_meta (int tagid, struct taginfo *tag, struct map_context *ctx)
515 char *name = find_attr (tag, "name", NULL);
516 char *http_equiv = find_attr (tag, "http-equiv", NULL);
518 if (http_equiv && 0 == strcasecmp (http_equiv, "refresh"))
520 /* Some pages use a META tag to specify that the page be
521 refreshed by a new page after a given number of seconds. The
522 general format for this is:
524 <meta http-equiv=Refresh content="NUMBER; URL=index2.html">
526 So we just need to skip past the "NUMBER; URL=" garbage to
529 struct urlpos *entry;
534 char *refresh = find_attr (tag, "content", &attrind);
538 for (p = refresh; c_isdigit (*p); p++)
539 timeout = 10 * timeout + *p - '0';
543 while (c_isspace (*p))
545 if (!( c_toupper (*p) == 'U'
546 && c_toupper (*(p + 1)) == 'R'
547 && c_toupper (*(p + 2)) == 'L'
551 while (c_isspace (*p))
554 entry = append_url (p, ATTR_POS(tag,attrind,ctx),
555 ATTR_SIZE(tag,attrind), ctx);
558 entry->link_refresh_p = 1;
559 entry->refresh_timeout = timeout;
560 entry->link_expect_html = 1;
563 else if (http_equiv && 0 == strcasecmp (http_equiv, "content-type"))
565 /* Handle stuff like:
566 <meta http-equiv="Content-Type" content="text/html; charset=CHARSET"> */
569 char *content = find_attr (tag, "content", NULL);
573 mcharset = parse_charset (content);
577 xfree_null (meta_charset);
578 meta_charset = mcharset;
580 else if (name && 0 == strcasecmp (name, "robots"))
582 /* Handle stuff like:
583 <meta name="robots" content="index,nofollow"> */
584 char *content = find_attr (tag, "content", NULL);
587 if (!strcasecmp (content, "none"))
588 ctx->nofollow = true;
593 /* Find the next occurrence of ',' or the end of
595 char *end = strchr (content, ',');
599 end = content + strlen (content);
600 if (!strncasecmp (content, "nofollow", end - content))
601 ctx->nofollow = true;
608 /* Dispatch the tag handler appropriate for the tag we're mapping
609 over. See known_tags[] for definition of tag handlers. */
612 collect_tags_mapper (struct taginfo *tag, void *arg)
614 struct map_context *ctx = (struct map_context *)arg;
616 /* Find the tag in our table of tags. This must not fail because
617 map_html_tags only returns tags found in interesting_tags.
619 I've changed this for now, I'm passing NULL as interesting_tags
620 to map_html_tags. This way we can check all tags for a style
623 struct known_tag *t = hash_table_get (interesting_tags, tag->name);
626 t->handler (t->tagid, tag, ctx);
628 check_style_attr (tag, ctx);
630 if (tag->end_tag_p && (0 == strcasecmp (tag->name, "style")) &&
631 tag->contents_begin && tag->contents_end)
634 get_urls_css (ctx, tag->contents_begin - ctx->text,
635 tag->contents_end - tag->contents_begin);
639 /* Analyze HTML tags FILE and construct a list of URLs referenced from
640 it. It merges relative links in FILE with URL. It is aware of
641 <base href=...> and does the right thing. */
644 get_urls_html (const char *file, const char *url, bool *meta_disallow_follow,
647 struct file_memory *fm;
648 struct map_context ctx;
652 fm = read_file (file);
655 logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
658 DEBUGP (("Loaded %s (size %s).\n", file, number_to_static_string (fm->length)));
660 ctx.text = fm->content;
661 ctx.head = ctx.tail = NULL;
663 ctx.parent_base = url ? url : opt.base_href;
664 ctx.document_file = file;
665 ctx.nofollow = false;
667 if (!interesting_tags)
670 /* Specify MHT_TRIM_VALUES because of buggy HTML generators that
671 generate <a href=" foo"> instead of <a href="foo"> (browsers
672 ignore spaces as well.) If you really mean space, use &32; or
673 %20. MHT_TRIM_VALUES also causes squashing of embedded newlines,
674 e.g. in <img src="foo.[newline]html">. Such newlines are also
675 ignored by IE and Mozilla and are presumably introduced by
676 writing HTML with editors that force word wrap. */
677 flags = MHT_TRIM_VALUES;
678 if (opt.strict_comments)
679 flags |= MHT_STRICT_COMMENTS;
681 /* the NULL here used to be interesting_tags */
682 map_html_tags (fm->content, fm->length, collect_tags_mapper, &ctx, flags,
683 NULL, interesting_attributes);
685 /* If meta charset isn't null, override content encoding */
686 if (iri && meta_charset)
687 set_content_encoding (iri, meta_charset);
689 DEBUGP (("no-follow in %s: %d\n", file, ctx.nofollow));
690 if (meta_disallow_follow)
691 *meta_disallow_follow = ctx.nofollow;
693 xfree_null (ctx.base);
698 /* This doesn't really have anything to do with HTML, but it's similar
699 to get_urls_html, so we put it here. */
702 get_urls_file (const char *file)
704 struct file_memory *fm;
705 struct urlpos *head, *tail;
706 const char *text, *text_end;
709 fm = read_file (file);
712 logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
715 DEBUGP (("Loaded %s (size %s).\n", file, number_to_static_string (fm->length)));
719 text_end = fm->content + fm->length;
720 while (text < text_end)
724 struct urlpos *entry;
727 const char *line_beg = text;
728 const char *line_end = memchr (text, '\n', text_end - text);
735 /* Strip whitespace from the beginning and end of line. */
736 while (line_beg < line_end && c_isspace (*line_beg))
738 while (line_end > line_beg && c_isspace (*(line_end - 1)))
741 if (line_beg == line_end)
744 /* The URL is in the [line_beg, line_end) region. */
746 /* We must copy the URL to a zero-terminated string, and we
747 can't use alloca because we're in a loop. *sigh*. */
748 url_text = strdupdelim (line_beg, line_end);
752 /* Merge opt.base_href with URL. */
753 char *merged = uri_merge (opt.base_href, url_text);
758 url = url_parse (url_text, &up_error_code, NULL, false);
761 char *error = url_error (url_text, up_error_code);
762 logprintf (LOG_NOTQUIET, _("%s: Invalid URL %s: %s\n"),
763 file, url_text, error);
770 entry = xnew0 (struct urlpos);
784 cleanup_html_url (void)
786 /* Destroy the hash tables. The hash table keys and values are not
787 allocated by this code, so we don't need to free them here. */
788 if (interesting_tags)
789 hash_table_destroy (interesting_tags);
790 if (interesting_attributes)
791 hash_table_destroy (interesting_attributes);