1 /* Handling of recursive HTTP retrieving.
2 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
3 2005, 2006, 2007, 2008, 2009, 2010 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. */
38 #endif /* HAVE_UNISTD_H */
55 /* Functions for maintaining the URL queue. */
57 struct queue_element {
58 const char *url; /* the URL to download */
59 const char *referer; /* the referring document */
60 int depth; /* the depth */
61 bool html_allowed; /* whether the document is allowed to
62 be treated as HTML. */
63 struct iri *iri; /* sXXXav */
64 bool css_allowed; /* whether the document is allowed to
66 struct queue_element *next; /* next element in queue */
70 struct queue_element *head;
71 struct queue_element *tail;
75 /* Create a URL queue. */
77 static struct url_queue *
80 struct url_queue *queue = xnew0 (struct url_queue);
84 /* Delete a URL queue. */
87 url_queue_delete (struct url_queue *queue)
92 /* Enqueue a URL in the queue. The queue is FIFO: the items will be
93 retrieved ("dequeued") from the queue in the order they were placed
97 url_enqueue (struct url_queue *queue, struct iri *i,
98 const char *url, const char *referer, int depth,
99 bool html_allowed, bool css_allowed)
101 struct queue_element *qel = xnew (struct queue_element);
104 qel->referer = referer;
106 qel->html_allowed = html_allowed;
107 qel->css_allowed = css_allowed;
111 if (queue->count > queue->maxcount)
112 queue->maxcount = queue->count;
114 DEBUGP (("Enqueuing %s at depth %d\n",
115 quotearg_n_style (0, escape_quoting_style, url), depth));
116 DEBUGP (("Queue count %d, maxcount %d.\n", queue->count, queue->maxcount));
119 DEBUGP (("[IRI Enqueuing %s with %s\n", quote_n (0, url),
120 i->uri_encoding ? quote_n (1, i->uri_encoding) : "None"));
123 queue->tail->next = qel;
127 queue->head = queue->tail;
130 /* Take a URL out of the queue. Return true if this operation
131 succeeded, or false if the queue is empty. */
134 url_dequeue (struct url_queue *queue, struct iri **i,
135 const char **url, const char **referer, int *depth,
136 bool *html_allowed, bool *css_allowed)
138 struct queue_element *qel = queue->head;
143 queue->head = queue->head->next;
149 *referer = qel->referer;
151 *html_allowed = qel->html_allowed;
152 *css_allowed = qel->css_allowed;
156 DEBUGP (("Dequeuing %s at depth %d\n",
157 quotearg_n_style (0, escape_quoting_style, qel->url), qel->depth));
158 DEBUGP (("Queue count %d, maxcount %d.\n", queue->count, queue->maxcount));
164 static bool download_child_p (const struct urlpos *, struct url *, int,
165 struct url *, struct hash_table *, struct iri *);
166 static bool descend_redirect_p (const char *, struct url *, int,
167 struct url *, struct hash_table *, struct iri *);
170 /* Retrieve a part of the web beginning with START_URL. This used to
171 be called "recursive retrieval", because the old function was
172 recursive and implemented depth-first search. retrieve_tree on the
173 other hand implements breadth-search traversal of the tree, which
174 results in much nicer ordering of downloads.
176 The algorithm this function uses is simple:
178 1. put START_URL in the queue.
179 2. while there are URLs in the queue:
181 3. get next URL from the queue.
183 5. if the URL is HTML and its depth does not exceed maximum depth,
184 get the list of URLs embedded therein.
185 6. for each of those URLs do the following:
187 7. if the URL is not one of those downloaded before, and if it
188 satisfies the criteria specified by the various command-line
189 options, add it to the queue. */
192 retrieve_tree (struct url *start_url_parsed, struct iri *pi)
194 uerr_t status = RETROK;
196 /* The queue of URLs we need to load. */
197 struct url_queue *queue;
199 /* The URLs we do not wish to enqueue, because they are already in
200 the queue, but haven't been downloaded yet. */
201 struct hash_table *blacklist;
204 struct iri *i = iri_new ();
206 #define COPYSTR(x) (x) ? xstrdup(x) : NULL;
207 /* Duplicate pi struct if not NULL */
210 i->uri_encoding = COPYSTR (pi->uri_encoding);
211 i->content_encoding = COPYSTR (pi->content_encoding);
212 i->utf8_encode = pi->utf8_encode;
215 set_uri_encoding (i, opt.locale, true);
218 queue = url_queue_new ();
219 blacklist = make_string_hash_table (0);
221 /* Enqueue the starting URL. Use start_url_parsed->url rather than
222 just URL so we enqueue the canonical form of the URL. */
223 url_enqueue (queue, i, xstrdup (start_url_parsed->url), NULL, 0, true,
225 string_set_add (blacklist, start_url_parsed->url);
229 bool descend = false;
230 char *url, *referer, *file = NULL;
232 bool html_allowed, css_allowed;
234 bool dash_p_leaf_HTML = false;
236 if (opt.quota && total_downloaded_bytes > opt.quota)
238 if (status == FWRITEERR)
241 /* Get the next URL from the queue... */
243 if (!url_dequeue (queue, (struct iri **) &i,
244 (const char **)&url, (const char **)&referer,
245 &depth, &html_allowed, &css_allowed))
248 /* ...and download it. Note that this download is in most cases
249 unconditional, as download_child_p already makes sure a file
250 doesn't get enqueued twice -- and yet this check is here, and
251 not in download_child_p. This is so that if you run `wget -r
252 URL1 URL2', and a random URL is encountered once under URL1
253 and again under URL2, but at a different (possibly smaller)
254 depth, we want the URL's children to be taken into account
256 if (dl_url_file_map && hash_table_contains (dl_url_file_map, url))
258 file = xstrdup (hash_table_get (dl_url_file_map, url));
260 DEBUGP (("Already downloaded \"%s\", reusing it from \"%s\".\n",
263 /* this sucks, needs to be combined! */
265 && downloaded_html_set
266 && string_set_contains (downloaded_html_set, file))
272 && downloaded_css_set
273 && string_set_contains (downloaded_css_set, file))
282 char *redirected = NULL;
283 struct url *url_parsed = url_parse (url, &url_err, i, true);
285 status = retrieve_url (url_parsed, url, &file, &redirected, referer,
286 &dt, false, i, true);
288 if (html_allowed && file && status == RETROK
289 && (dt & RETROKF) && (dt & TEXTHTML))
295 /* a little different, css_allowed can override content type
296 lots of web servers serve css with an incorrect content type
298 if (file && status == RETROK
300 ((dt & TEXTCSS) || css_allowed))
308 /* We have been redirected, possibly to another host, or
309 different path, or wherever. Check whether we really
310 want to follow it. */
313 if (!descend_redirect_p (redirected, url_parsed, depth,
314 start_url_parsed, blacklist, i))
317 /* Make sure that the old pre-redirect form gets
319 string_set_add (blacklist, url);
328 url = xstrdup (url_parsed->url);
330 url_free(url_parsed);
335 visited_url (url, referer);
339 && depth >= opt.reclevel && opt.reclevel != INFINITE_RECURSION)
341 if (opt.page_requisites
342 && (depth == opt.reclevel || depth == opt.reclevel + 1))
344 /* When -p is specified, we are allowed to exceed the
345 maximum depth, but only for the "inline" links,
346 i.e. those that are needed to display the page.
347 Originally this could exceed the depth at most by
348 one, but we allow one more level so that the leaf
349 pages that contain frames can be loaded
351 dash_p_leaf_HTML = true;
355 /* Either -p wasn't specified or it was and we've
356 already spent the two extra (pseudo-)levels that it
357 affords us, so we need to bail out. */
358 DEBUGP (("Not descending further; at depth %d, max. %d.\n",
359 depth, opt.reclevel));
364 /* If the downloaded document was HTML or CSS, parse it and enqueue the
365 links it contains. */
369 bool meta_disallow_follow = false;
370 struct urlpos *children
371 = is_css ? get_urls_css_file (file, url) :
372 get_urls_html (file, url, &meta_disallow_follow, i);
374 if (opt.use_robots && meta_disallow_follow)
376 free_urlpos (children);
382 struct urlpos *child = children;
383 struct url *url_parsed = url_parse (url, NULL, i, true);
385 char *referer_url = url;
386 bool strip_auth = (url_parsed != NULL
387 && url_parsed->user != NULL);
388 assert (url_parsed != NULL);
390 /* Strip auth info if present */
392 referer_url = url_string (url_parsed, URL_AUTH_HIDE);
394 for (; child; child = child->next)
396 if (child->ignore_when_downloading)
398 if (dash_p_leaf_HTML && !child->link_inline_p)
400 if (download_child_p (child, url_parsed, depth, start_url_parsed,
404 set_uri_encoding (ci, i->content_encoding, false);
405 url_enqueue (queue, ci, xstrdup (child->url->url),
406 xstrdup (referer_url), depth + 1,
407 child->link_expect_html,
408 child->link_expect_css);
409 /* We blacklist the URL we have enqueued, because we
410 don't want to enqueue (and hence download) the
412 string_set_add (blacklist, child->url->url);
418 url_free (url_parsed);
419 free_urlpos (children);
425 || opt.spider /* opt.recursive is implicitely true */
426 || !acceptable (file)))
428 /* Either --delete-after was specified, or we loaded this
429 (otherwise unneeded because of --spider or rejected by -R)
430 HTML file just to harvest its hyperlinks -- in either case,
431 delete the local file. */
432 DEBUGP (("Removing file due to %s in recursive_retrieve():\n",
433 opt.delete_after ? "--delete-after" :
434 (opt.spider ? "--spider" :
435 "recursive rejection criteria")));
436 logprintf (LOG_VERBOSE,
437 (opt.delete_after || opt.spider
438 ? _("Removing %s.\n")
439 : _("Removing %s since it should be rejected.\n")),
442 logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno));
443 logputs (LOG_VERBOSE, "\n");
444 register_delete_file (file);
448 xfree_null (referer);
453 /* If anything is left of the queue due to a premature exit, free it
460 while (url_dequeue (queue, (struct iri **)&d6,
461 (const char **)&d1, (const char **)&d2, &d3, &d4, &d5))
468 url_queue_delete (queue);
470 string_set_free (blacklist);
472 if (opt.quota && total_downloaded_bytes > opt.quota)
474 else if (status == FWRITEERR)
480 /* Based on the context provided by retrieve_tree, decide whether a
481 URL is to be descended to. This is only ever called from
482 retrieve_tree, but is in a separate function for clarity.
484 The most expensive checks (such as those for robots) are memoized
485 by storing these URLs to BLACKLIST. This may or may not help. It
486 will help if those URLs are encountered many times. */
489 download_child_p (const struct urlpos *upos, struct url *parent, int depth,
490 struct url *start_url_parsed, struct hash_table *blacklist,
493 struct url *u = upos->url;
494 const char *url = u->url;
495 bool u_scheme_like_http;
497 DEBUGP (("Deciding whether to enqueue \"%s\".\n", url));
499 if (string_set_contains (blacklist, url))
503 char *referrer = url_string (parent, URL_AUTH_HIDE_PASSWD);
504 DEBUGP (("download_child_p: parent->url is: %s\n", quote (parent->url)));
505 visited_url (url, referrer);
508 DEBUGP (("Already on the black list.\n"));
512 /* Several things to check for:
513 1. if scheme is not http, and we don't load it
514 2. check for relative links (if relative_only is set)
516 4. check for no-parent
517 5. check for excludes && includes
519 7. check for same host (if spanhost is unset), with possible
520 gethostbyname baggage
521 8. check for robots.txt
523 Addendum: If the URL is FTP, and it is to be loaded, only the
524 domain and suffix settings are "stronger".
526 Note that .html files will get loaded regardless of suffix rules
527 (but that is remedied later with unlink) unless the depth equals
530 More time- and memory- consuming tests should be put later on
533 /* Determine whether URL under consideration has a HTTP-like scheme. */
534 u_scheme_like_http = schemes_are_similar_p (u->scheme, SCHEME_HTTP);
536 /* 1. Schemes other than HTTP are normally not recursed into. */
537 if (!u_scheme_like_http && !(u->scheme == SCHEME_FTP && opt.follow_ftp))
539 DEBUGP (("Not following non-HTTP schemes.\n"));
543 /* 2. If it is an absolute link and they are not followed, throw it
545 if (u_scheme_like_http)
546 if (opt.relative_only && !upos->link_relative_p)
548 DEBUGP (("It doesn't really look like a relative link.\n"));
552 /* 3. If its domain is not to be accepted/looked-up, chuck it
554 if (!accept_domain (u))
556 DEBUGP (("The domain was not accepted.\n"));
560 /* 4. Check for parent directory.
562 If we descended to a different host or changed the scheme, ignore
563 opt.no_parent. Also ignore it for documents needed to display
564 the parent page when in -p mode. */
566 && schemes_are_similar_p (u->scheme, start_url_parsed->scheme)
567 && 0 == strcasecmp (u->host, start_url_parsed->host)
568 && u->port == start_url_parsed->port
569 && !(opt.page_requisites && upos->link_inline_p))
571 if (!subdir_p (start_url_parsed->dir, u->dir))
573 DEBUGP (("Going to \"%s\" would escape \"%s\" with no_parent on.\n",
574 u->dir, start_url_parsed->dir));
579 /* 5. If the file does not match the acceptance list, or is on the
580 rejection list, chuck it out. The same goes for the directory
581 exclusion and inclusion lists. */
582 if (opt.includes || opt.excludes)
584 if (!accdir (u->dir))
586 DEBUGP (("%s (%s) is excluded/not-included.\n", url, u->dir));
591 /* 6. Check for acceptance/rejection rules. We ignore these rules
592 for directories (no file name to match) and for non-leaf HTMLs,
593 which can lead to other files that do need to be downloaded. (-p
594 automatically implies non-leaf because with -p we can, if
595 necesary, overstep the maximum depth to get the page requisites.) */
596 if (u->file[0] != '\0'
597 && !(has_html_suffix_p (u->file)
598 /* The exception only applies to non-leaf HTMLs (but -p
599 always implies non-leaf because we can overstep the
600 maximum depth to get the requisites): */
602 opt.reclevel == INFINITE_RECURSION
604 || depth < opt.reclevel - 1
605 /* -p, which implies non-leaf (see above) */
606 || opt.page_requisites)))
608 if (!acceptable (u->file))
610 DEBUGP (("%s (%s) does not match acc/rej rules.\n",
617 if (schemes_are_similar_p (u->scheme, parent->scheme))
618 if (!opt.spanhost && 0 != strcasecmp (parent->host, u->host))
620 DEBUGP (("This is not the same hostname as the parent's (%s and %s).\n",
621 u->host, parent->host));
626 if (opt.use_robots && u_scheme_like_http)
628 struct robot_specs *specs = res_get_specs (u->host, u->port);
632 if (res_retrieve_file (url, &rfile, iri))
634 specs = res_parse_from_file (rfile);
636 /* Delete the robots.txt file if we chose to either delete the
637 files after downloading or we're just running a spider. */
638 if (opt.delete_after || opt.spider)
640 logprintf (LOG_VERBOSE, "Removing %s.\n", rfile);
642 logprintf (LOG_NOTQUIET, "unlink: %s\n",
650 /* If we cannot get real specs, at least produce
651 dummy ones so that we can register them and stop
652 trying to retrieve them. */
653 specs = res_parse ("", 0);
655 res_register_specs (u->host, u->port, specs);
658 /* Now that we have (or don't have) robots.txt specs, we can
659 check what they say. */
660 if (!res_match_path (specs, u->path))
662 DEBUGP (("Not following %s because robots.txt forbids it.\n", url));
663 string_set_add (blacklist, url);
668 /* The URL has passed all the tests. It can be placed in the
670 DEBUGP (("Decided to load it.\n"));
675 DEBUGP (("Decided NOT to load it.\n"));
680 /* This function determines whether we will consider downloading the
681 children of a URL whose download resulted in a redirection,
682 possibly to another host, etc. It is needed very rarely, and thus
683 it is merely a simple-minded wrapper around download_child_p. */
686 descend_redirect_p (const char *redirected, struct url *orig_parsed, int depth,
687 struct url *start_url_parsed, struct hash_table *blacklist,
690 struct url *new_parsed;
694 assert (orig_parsed != NULL);
696 new_parsed = url_parse (redirected, NULL, NULL, false);
697 assert (new_parsed != NULL);
699 upos = xnew0 (struct urlpos);
700 upos->url = new_parsed;
702 success = download_child_p (upos, orig_parsed, depth,
703 start_url_parsed, blacklist, iri);
705 url_free (new_parsed);
709 DEBUGP (("Redirection \"%s\" failed the test.\n", redirected));
714 /* vim:set sts=2 sw=2 cino+={s: */