1 /* Handling of recursive HTTP retrieving.
2 Copyright (C) 1995, 1996, 1997, 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GNU Wget.
6 GNU Wget is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 GNU Wget is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with Wget; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 In addition, as a special exception, the Free Software Foundation
21 gives permission to link the code of its release of Wget with the
22 OpenSSL project's "OpenSSL" library (or with modified versions of it
23 that use the same license as the "OpenSSL" library), and distribute
24 the linked executables. You must obey the GNU General Public License
25 in all respects for all of the code used other than "OpenSSL". If you
26 modify this file, you may extend this exception to your version of the
27 file, but you are not obligated to do so. If you do not wish to do
28 so, delete this exception statement from your version. */
38 #endif /* HAVE_STRING_H */
41 #endif /* HAVE_UNISTD_H */
44 #include <sys/types.h>
61 extern char *version_string;
63 static struct hash_table *dl_file_url_map;
64 static struct hash_table *dl_url_file_map;
66 /* List of HTML files downloaded in this Wget run, used for link
67 conversion after Wget is done. The list and the set contain the
68 same information, except the list maintains the order. Perhaps I
69 should get rid of the list, it's there for historical reasons. */
70 static slist *downloaded_html_list;
71 static struct hash_table *downloaded_html_set;
73 static void register_delete_file PARAMS ((const char *));
75 /* Functions for maintaining the URL queue. */
77 struct queue_element {
81 struct queue_element *next;
85 struct queue_element *head;
86 struct queue_element *tail;
90 /* Create a URL queue. */
92 static struct url_queue *
95 struct url_queue *queue = xmalloc (sizeof (*queue));
96 memset (queue, '\0', sizeof (*queue));
100 /* Delete a URL queue. */
103 url_queue_delete (struct url_queue *queue)
108 /* Enqueue a URL in the queue. The queue is FIFO: the items will be
109 retrieved ("dequeued") from the queue in the order they were placed
113 url_enqueue (struct url_queue *queue,
114 const char *url, const char *referer, int depth)
116 struct queue_element *qel = xmalloc (sizeof (*qel));
118 qel->referer = referer;
123 if (queue->count > queue->maxcount)
124 queue->maxcount = queue->count;
126 DEBUGP (("Enqueuing %s at depth %d\n", url, depth));
127 DEBUGP (("Queue count %d, maxcount %d.\n", queue->count, queue->maxcount));
130 queue->tail->next = qel;
134 queue->head = queue->tail;
137 /* Take a URL out of the queue. Return 1 if this operation succeeded,
138 or 0 if the queue is empty. */
141 url_dequeue (struct url_queue *queue,
142 const char **url, const char **referer, int *depth)
144 struct queue_element *qel = queue->head;
149 queue->head = queue->head->next;
154 *referer = qel->referer;
159 DEBUGP (("Dequeuing %s at depth %d\n", qel->url, qel->depth));
160 DEBUGP (("Queue count %d, maxcount %d.\n", queue->count, queue->maxcount));
166 static int download_child_p PARAMS ((const struct urlpos *, struct url *, int,
167 struct url *, struct hash_table *));
168 static int descend_redirect_p PARAMS ((const char *, const char *, int,
169 struct url *, struct hash_table *));
172 /* Retrieve a part of the web beginning with START_URL. This used to
173 be called "recursive retrieval", because the old function was
174 recursive and implemented depth-first search. retrieve_tree on the
175 other hand implements breadth-search traversal of the tree, which
176 results in much nicer ordering of downloads.
178 The algorithm this function uses is simple:
180 1. put START_URL in the queue.
181 2. while there are URLs in the queue:
183 3. get next URL from the queue.
185 5. if the URL is HTML and its depth does not exceed maximum depth,
186 get the list of URLs embedded therein.
187 6. for each of those URLs do the following:
189 7. if the URL is not one of those downloaded before, and if it
190 satisfies the criteria specified by the various command-line
191 options, add it to the queue. */
194 retrieve_tree (const char *start_url)
196 uerr_t status = RETROK;
198 /* The queue of URLs we need to load. */
199 struct url_queue *queue;
201 /* The URLs we do not wish to enqueue, because they are already in
202 the queue, but haven't been downloaded yet. */
203 struct hash_table *blacklist;
206 struct url *start_url_parsed = url_parse (start_url, &up_error_code);
208 if (!start_url_parsed)
210 logprintf (LOG_NOTQUIET, "%s: %s.\n", start_url,
211 url_error (up_error_code));
215 queue = url_queue_new ();
216 blacklist = make_string_hash_table (0);
218 /* Enqueue the starting URL. Use start_url_parsed->url rather than
219 just URL so we enqueue the canonical form of the URL. */
220 url_enqueue (queue, xstrdup (start_url_parsed->url), NULL, 0);
221 string_set_add (blacklist, start_url_parsed->url);
226 char *url, *referer, *file = NULL;
228 boolean dash_p_leaf_HTML = FALSE;
230 if (downloaded_exceeds_quota ())
232 if (status == FWRITEERR)
235 /* Get the next URL from the queue... */
237 if (!url_dequeue (queue,
238 (const char **)&url, (const char **)&referer,
242 /* ...and download it. Note that this download is in most cases
243 unconditional, as download_child_p already makes sure a file
244 doesn't get enqueued twice -- and yet this check is here, and
245 not in download_child_p. This is so that if you run `wget -r
246 URL1 URL2', and a random URL is encountered once under URL1
247 and again under URL2, but at a different (possibly smaller)
248 depth, we want the URL's children to be taken into account
250 if (dl_url_file_map && hash_table_contains (dl_url_file_map, url))
252 file = xstrdup (hash_table_get (dl_url_file_map, url));
254 DEBUGP (("Already downloaded \"%s\", reusing it from \"%s\".\n",
257 if (string_set_contains (downloaded_html_set, file))
263 char *redirected = NULL;
264 int oldrec = opt.recursive;
267 status = retrieve_url (url, &file, &redirected, referer, &dt);
268 opt.recursive = oldrec;
270 if (file && status == RETROK
271 && (dt & RETROKF) && (dt & TEXTHTML))
276 /* We have been redirected, possibly to another host, or
277 different path, or wherever. Check whether we really
278 want to follow it. */
281 if (!descend_redirect_p (redirected, url, depth,
282 start_url_parsed, blacklist))
285 /* Make sure that the old pre-redirect form gets
287 string_set_add (blacklist, url);
296 && depth >= opt.reclevel && opt.reclevel != INFINITE_RECURSION)
298 if (opt.page_requisites
299 && (depth == opt.reclevel || depth == opt.reclevel + 1))
301 /* When -p is specified, we are allowed to exceed the
302 maximum depth, but only for the "inline" links,
303 i.e. those that are needed to display the page.
304 Originally this could exceed the depth at most by
305 one, but we allow one more level so that the leaf
306 pages that contain frames can be loaded
308 dash_p_leaf_HTML = TRUE;
312 /* Either -p wasn't specified or it was and we've
313 already spent the two extra (pseudo-)levels that it
314 affords us, so we need to bail out. */
315 DEBUGP (("Not descending further; at depth %d, max. %d.\n",
316 depth, opt.reclevel));
321 /* If the downloaded document was HTML, parse it and enqueue the
322 links it contains. */
326 int meta_disallow_follow = 0;
327 struct urlpos *children
328 = get_urls_html (file, url, &meta_disallow_follow);
330 if (opt.use_robots && meta_disallow_follow)
332 free_urlpos (children);
338 struct urlpos *child = children;
339 struct url *url_parsed = url_parsed = url_parse (url, NULL);
340 assert (url_parsed != NULL);
342 for (; child; child = child->next)
344 if (child->ignore_when_downloading)
346 if (dash_p_leaf_HTML && !child->link_inline_p)
348 if (download_child_p (child, url_parsed, depth, start_url_parsed,
351 url_enqueue (queue, xstrdup (child->url->url),
352 xstrdup (url), depth + 1);
353 /* We blacklist the URL we have enqueued, because we
354 don't want to enqueue (and hence download) the
356 string_set_add (blacklist, child->url->url);
360 url_free (url_parsed);
361 free_urlpos (children);
365 if (opt.delete_after || (file && !acceptable (file)))
367 /* Either --delete-after was specified, or we loaded this
368 otherwise rejected (e.g. by -R) HTML file just so we
369 could harvest its hyperlinks -- in either case, delete
371 DEBUGP (("Removing file due to %s in recursive_retrieve():\n",
372 opt.delete_after ? "--delete-after" :
373 "recursive rejection criteria"));
374 logprintf (LOG_VERBOSE,
376 ? _("Removing %s.\n")
377 : _("Removing %s since it should be rejected.\n")),
380 logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno));
381 register_delete_file (file);
385 FREE_MAYBE (referer);
389 /* If anything is left of the queue due to a premature exit, free it
394 while (url_dequeue (queue, (const char **)&d1, (const char **)&d2, &d3))
400 url_queue_delete (queue);
402 if (start_url_parsed)
403 url_free (start_url_parsed);
404 string_set_free (blacklist);
406 if (downloaded_exceeds_quota ())
408 else if (status == FWRITEERR)
414 /* Based on the context provided by retrieve_tree, decide whether a
415 URL is to be descended to. This is only ever called from
416 retrieve_tree, but is in a separate function for clarity.
418 The most expensive checks (such as those for robots) are memoized
419 by storing these URLs to BLACKLIST. This may or may not help. It
420 will help if those URLs are encountered many times. */
423 download_child_p (const struct urlpos *upos, struct url *parent, int depth,
424 struct url *start_url_parsed, struct hash_table *blacklist)
426 struct url *u = upos->url;
427 const char *url = u->url;
428 int u_scheme_like_http;
430 DEBUGP (("Deciding whether to enqueue \"%s\".\n", url));
432 if (string_set_contains (blacklist, url))
434 DEBUGP (("Already on the black list.\n"));
438 /* Several things to check for:
439 1. if scheme is not http, and we don't load it
440 2. check for relative links (if relative_only is set)
442 4. check for no-parent
443 5. check for excludes && includes
445 7. check for same host (if spanhost is unset), with possible
446 gethostbyname baggage
447 8. check for robots.txt
449 Addendum: If the URL is FTP, and it is to be loaded, only the
450 domain and suffix settings are "stronger".
452 Note that .html files will get loaded regardless of suffix rules
453 (but that is remedied later with unlink) unless the depth equals
456 More time- and memory- consuming tests should be put later on
459 /* Determine whether URL under consideration has a HTTP-like scheme. */
460 u_scheme_like_http = schemes_are_similar_p (u->scheme, SCHEME_HTTP);
462 /* 1. Schemes other than HTTP are normally not recursed into. */
463 if (!u_scheme_like_http && !(u->scheme == SCHEME_FTP && opt.follow_ftp))
465 DEBUGP (("Not following non-HTTP schemes.\n"));
469 /* 2. If it is an absolute link and they are not followed, throw it
471 if (u_scheme_like_http)
472 if (opt.relative_only && !upos->link_relative_p)
474 DEBUGP (("It doesn't really look like a relative link.\n"));
478 /* 3. If its domain is not to be accepted/looked-up, chuck it
480 if (!accept_domain (u))
482 DEBUGP (("The domain was not accepted.\n"));
486 /* 4. Check for parent directory.
488 If we descended to a different host or changed the scheme, ignore
489 opt.no_parent. Also ignore it for documents needed to display
490 the parent page when in -p mode. */
492 && schemes_are_similar_p (u->scheme, start_url_parsed->scheme)
493 && 0 == strcasecmp (u->host, start_url_parsed->host)
494 && u->port == start_url_parsed->port
495 && !(opt.page_requisites && upos->link_inline_p))
497 if (!frontcmp (start_url_parsed->dir, u->dir))
499 DEBUGP (("Going to \"%s\" would escape \"%s\" with no_parent on.\n",
500 u->dir, start_url_parsed->dir));
505 /* 5. If the file does not match the acceptance list, or is on the
506 rejection list, chuck it out. The same goes for the directory
507 exclusion and inclusion lists. */
508 if (opt.includes || opt.excludes)
510 if (!accdir (u->dir, ALLABS))
512 DEBUGP (("%s (%s) is excluded/not-included.\n", url, u->dir));
517 /* 6. Check for acceptance/rejection rules. We ignore these rules
518 for directories (no file name to match) and for HTML documents,
519 which might lead to other files that do need to be downloaded.
520 That is, unless we've exhausted the recursion depth anyway. */
521 if (u->file[0] != '\0'
522 && !(has_html_suffix_p (u->file)
523 && depth != INFINITE_RECURSION
524 && depth < opt.reclevel - 1))
526 if (!acceptable (u->file))
528 DEBUGP (("%s (%s) does not match acc/rej rules.\n",
535 if (schemes_are_similar_p (u->scheme, parent->scheme))
536 if (!opt.spanhost && 0 != strcasecmp (parent->host, u->host))
538 DEBUGP (("This is not the same hostname as the parent's (%s and %s).\n",
539 u->host, parent->host));
544 if (opt.use_robots && u_scheme_like_http)
546 struct robot_specs *specs = res_get_specs (u->host, u->port);
550 if (res_retrieve_file (url, &rfile))
552 specs = res_parse_from_file (rfile);
557 /* If we cannot get real specs, at least produce
558 dummy ones so that we can register them and stop
559 trying to retrieve them. */
560 specs = res_parse ("", 0);
562 res_register_specs (u->host, u->port, specs);
565 /* Now that we have (or don't have) robots.txt specs, we can
566 check what they say. */
567 if (!res_match_path (specs, u->path))
569 DEBUGP (("Not following %s because robots.txt forbids it.\n", url));
570 string_set_add (blacklist, url);
575 /* The URL has passed all the tests. It can be placed in the
577 DEBUGP (("Decided to load it.\n"));
582 DEBUGP (("Decided NOT to load it.\n"));
587 /* This function determines whether we will consider downloading the
588 children of a URL whose download resulted in a redirection,
589 possibly to another host, etc. It is needed very rarely, and thus
590 it is merely a simple-minded wrapper around download_child_p. */
593 descend_redirect_p (const char *redirected, const char *original, int depth,
594 struct url *start_url_parsed, struct hash_table *blacklist)
596 struct url *orig_parsed, *new_parsed;
600 orig_parsed = url_parse (original, NULL);
601 assert (orig_parsed != NULL);
603 new_parsed = url_parse (redirected, NULL);
604 assert (new_parsed != NULL);
606 upos = xmalloc (sizeof (struct urlpos));
607 memset (upos, 0, sizeof (*upos));
608 upos->url = new_parsed;
610 success = download_child_p (upos, orig_parsed, depth,
611 start_url_parsed, blacklist);
613 url_free (orig_parsed);
614 url_free (new_parsed);
618 DEBUGP (("Redirection \"%s\" failed the test.\n", redirected));
624 #define ENSURE_TABLES_EXIST do { \
625 if (!dl_file_url_map) \
626 dl_file_url_map = make_string_hash_table (0); \
627 if (!dl_url_file_map) \
628 dl_url_file_map = make_string_hash_table (0); \
631 /* Return 1 if S1 and S2 are the same, except for "/index.html". The
632 three cases in which it returns one are (substitute any substring
635 m("foo/index.html", "foo/") ==> 1
636 m("foo/", "foo/index.html") ==> 1
637 m("foo", "foo/index.html") ==> 1
638 m("foo", "foo/" ==> 1
639 m("foo", "foo") ==> 1 */
642 match_except_index (const char *s1, const char *s2)
647 /* Skip common substring. */
648 for (i = 0; *s1 && *s2 && *s1 == *s2; s1++, s2++, i++)
651 /* Strings differ at the very beginning -- bail out. We need to
652 check this explicitly to avoid `lng - 1' reading outside the
657 /* Both strings hit EOF -- strings are equal. */
660 /* Strings are randomly different, e.g. "/foo/bar" and "/foo/qux". */
663 /* S1 is the longer one. */
666 /* S2 is the longer one. */
670 /* foo/index.html */ /* or */ /* foo/index.html */
674 /* The right-hand case. */
677 if (*lng == '/' && *(lng + 1) == '\0')
682 return 0 == strcmp (lng, "/index.html");
686 dissociate_urls_from_file_mapper (void *key, void *value, void *arg)
688 char *mapping_url = (char *)key;
689 char *mapping_file = (char *)value;
690 char *file = (char *)arg;
692 if (0 == strcmp (mapping_file, file))
694 hash_table_remove (dl_url_file_map, mapping_url);
696 xfree (mapping_file);
699 /* Continue mapping. */
703 /* Remove all associations from various URLs to FILE from dl_url_file_map. */
706 dissociate_urls_from_file (const char *file)
708 hash_table_map (dl_url_file_map, dissociate_urls_from_file_mapper,
712 /* Register that URL has been successfully downloaded to FILE. This
713 is used by the link conversion code to convert references to URLs
714 to references to local files. It is also being used to check if a
715 URL has already been downloaded. */
718 register_download (const char *url, const char *file)
720 char *old_file, *old_url;
724 /* With some forms of retrieval, it is possible, although not likely
725 or particularly desirable. If both are downloaded, the second
726 download will override the first one. When that happens,
727 dissociate the old file name from the URL. */
729 if (hash_table_get_pair (dl_file_url_map, file, &old_file, &old_url))
731 if (0 == strcmp (url, old_url))
732 /* We have somehow managed to download the same URL twice.
736 if (match_except_index (url, old_url)
737 && !hash_table_contains (dl_url_file_map, url))
738 /* The two URLs differ only in the "index.html" ending. For
739 example, one is "http://www.server.com/", and the other is
740 "http://www.server.com/index.html". Don't remove the old
741 one, just add the new one as a non-canonical entry. */
744 hash_table_remove (dl_file_url_map, file);
748 /* Remove all the URLs that point to this file. Yes, there can
749 be more than one such URL, because we store redirections as
750 multiple entries in dl_url_file_map. For example, if URL1
751 redirects to URL2 which gets downloaded to FILE, we map both
752 URL1 and URL2 to FILE in dl_url_file_map. (dl_file_url_map
753 only points to URL2.) When another URL gets loaded to FILE,
754 we want both URL1 and URL2 dissociated from it.
756 This is a relatively expensive operation because it performs
757 a linear search of the whole hash table, but it should be
758 called very rarely, only when two URLs resolve to the same
759 file name, *and* the "<file>.1" extensions are turned off.
760 In other words, almost never. */
761 dissociate_urls_from_file (file);
764 hash_table_put (dl_file_url_map, xstrdup (file), xstrdup (url));
767 /* A URL->FILE mapping is not possible without a FILE->URL mapping.
768 If the latter were present, it should have been removed by the
769 above `if'. So we could write:
771 assert (!hash_table_contains (dl_url_file_map, url));
773 The above is correct when running in recursive mode where the
774 same URL always resolves to the same file. But if you do
779 then the first URL will resolve to "FILE", and the other to
780 "FILE.1". In that case, FILE.1 will not be found in
781 dl_file_url_map, but URL will still point to FILE in
783 if (hash_table_get_pair (dl_url_file_map, url, &old_url, &old_file))
785 hash_table_remove (dl_url_file_map, url);
790 hash_table_put (dl_url_file_map, xstrdup (url), xstrdup (file));
793 /* Register that FROM has been redirected to TO. This assumes that TO
794 is successfully downloaded and already registered using
795 register_download() above. */
798 register_redirection (const char *from, const char *to)
804 file = hash_table_get (dl_url_file_map, to);
805 assert (file != NULL);
806 if (!hash_table_contains (dl_url_file_map, from))
807 hash_table_put (dl_url_file_map, xstrdup (from), xstrdup (file));
810 /* Register that the file has been deleted. */
813 register_delete_file (const char *file)
815 char *old_url, *old_file;
819 if (!hash_table_get_pair (dl_file_url_map, file, &old_file, &old_url))
822 hash_table_remove (dl_file_url_map, file);
825 dissociate_urls_from_file (file);
828 /* Register that FILE is an HTML file that has been downloaded. */
831 register_html (const char *url, const char *file)
833 if (!downloaded_html_set)
834 downloaded_html_set = make_string_hash_table (0);
835 else if (hash_table_contains (downloaded_html_set, file))
838 /* The set and the list should use the same copy of FILE, but the
839 slist interface insists on strduping the string it gets. Oh
841 string_set_add (downloaded_html_set, file);
842 downloaded_html_list = slist_prepend (downloaded_html_list, file);
845 /* This function is called when the retrieval is done to convert the
846 links that have been downloaded. It has to be called at the end of
847 the retrieval, because only then does Wget know conclusively which
848 URLs have been downloaded, and which not, so it can tell which
849 direction to convert to.
851 The "direction" means that the URLs to the files that have been
852 downloaded get converted to the relative URL which will point to
853 that file. And the other URLs get converted to the remote URL on
856 All the downloaded HTMLs are kept in downloaded_html_files, and
857 downloaded URLs in urls_downloaded. All the information is
858 extracted from these two lists. */
861 convert_all_links (void)
867 struct wget_timer *timer = wtimer_new ();
869 /* Destructively reverse downloaded_html_files to get it in the right order.
870 recursive_retrieve() used slist_prepend() consistently. */
871 downloaded_html_list = slist_nreverse (downloaded_html_list);
873 for (html = downloaded_html_list; html; html = html->next)
875 struct urlpos *urls, *cur_url;
877 char *file = html->string;
879 /* Determine the URL of the HTML file. get_urls_html will need
881 url = hash_table_get (dl_file_url_map, file);
884 DEBUGP (("Apparently %s has been removed.\n", file));
888 DEBUGP (("Scanning %s (from %s)\n", file, url));
890 /* Parse the HTML file... */
891 urls = get_urls_html (file, url, NULL);
893 /* We don't respect meta_disallow_follow here because, even if
894 the file is not followed, we might still want to convert the
895 links that have been followed from other files. */
897 for (cur_url = urls; cur_url; cur_url = cur_url->next)
900 struct url *u = cur_url->url;
902 if (cur_url->link_base_p)
904 /* Base references have been resolved by our parser, so
905 we turn the base URL into an empty string. (Perhaps
906 we should remove the tag entirely?) */
907 cur_url->convert = CO_NULLIFY_BASE;
911 /* We decide the direction of conversion according to whether
912 a URL was downloaded. Downloaded URLs will be converted
913 ABS2REL, whereas non-downloaded will be converted REL2ABS. */
914 local_name = hash_table_get (dl_url_file_map, u->url);
916 /* Decide on the conversion type. */
919 /* We've downloaded this URL. Convert it to relative
920 form. We do this even if the URL already is in
921 relative form, because our directory structure may
922 not be identical to that on the server (think `-nd',
923 `--cut-dirs', etc.) */
924 cur_url->convert = CO_CONVERT_TO_RELATIVE;
925 cur_url->local_name = xstrdup (local_name);
926 DEBUGP (("will convert url %s to local %s\n", u->url, local_name));
930 /* We haven't downloaded this URL. If it's not already
931 complete (including a full host name), convert it to
932 that form, so it can be reached while browsing this
934 if (!cur_url->link_complete_p)
935 cur_url->convert = CO_CONVERT_TO_COMPLETE;
936 cur_url->local_name = NULL;
937 DEBUGP (("will convert url %s to complete\n", u->url));
941 /* Convert the links in the file. */
942 convert_links (file, urls);
949 msecs = wtimer_elapsed (timer);
950 wtimer_delete (timer);
951 logprintf (LOG_VERBOSE, _("Converted %d files in %.2f seconds.\n"),
952 file_count, (double)msecs / 1000);
955 /* Cleanup the data structures associated with recursive retrieving
956 (the variables above). */
958 recursive_cleanup (void)
962 free_keys_and_values (dl_file_url_map);
963 hash_table_destroy (dl_file_url_map);
964 dl_file_url_map = NULL;
968 free_keys_and_values (dl_url_file_map);
969 hash_table_destroy (dl_url_file_map);
970 dl_url_file_map = NULL;
972 if (downloaded_html_set)
973 string_set_free (downloaded_html_set);
974 slist_free (downloaded_html_list);
975 downloaded_html_list = NULL;