Wordpress 2.7.1
[autoinstalls/wordpress.git] / wp-includes / canonical.php
1 <?php
2 /**
3  * Canonical API to handle WordPress Redirecting
4  *
5  * Based on "Permalink Redirect" from Scott Yang and "Enforce www. Preference"
6  * by Mark Jaquith
7  *
8  * @author Scott Yang
9  * @author Mark Jaquith
10  * @package WordPress
11  * @since 2.3.0
12  */
13
14 /**
15  * Redirects incoming links to the proper URL based on the site url.
16  *
17  * Search engines consider www.somedomain.com and somedomain.com to be two
18  * different URLs when they both go to the same location. This SEO enhancement
19  * prevents penality for duplicate content by redirecting all incoming links to
20  * one or the other.
21  *
22  * Prevents redirection for feeds, trackbacks, searches, comment popup, and
23  * admin URLs. Does not redirect on IIS, page/post previews, and on form data.
24  *
25  * Will also attempt to find the correct link when a user enters a URL that does
26  * not exist based on exact WordPress query. Will instead try to parse the URL
27  * or query in an attempt to figure the correct page to go to.
28  *
29  * @since 2.3.0
30  * @uses $wp_rewrite
31  * @uses $is_IIS
32  *
33  * @param string $requested_url Optional. The URL that was requested, used to
34  *              figure if redirect is needed.
35  * @param bool $do_redirect Optional. Redirect to the new URL.
36  * @return null|false|string Null, if redirect not needed. False, if redirect
37  *              not needed or the string of the URL
38  */
39 function redirect_canonical($requested_url=null, $do_redirect=true) {
40         global $wp_rewrite, $is_IIS, $wp_query, $wpdb;
41
42         if ( is_trackback() || is_search() || is_comments_popup() || is_admin() || $is_IIS || ( isset($_POST) && count($_POST) ) || is_preview() || is_robots() )
43                 return;
44
45         if ( !$requested_url ) {
46                 // build the URL in the address bar
47                 $requested_url  = ( !empty($_SERVER['HTTPS'] ) && strtolower($_SERVER['HTTPS']) == 'on' ) ? 'https://' : 'http://';
48                 $requested_url .= $_SERVER['HTTP_HOST'];
49                 $requested_url .= $_SERVER['REQUEST_URI'];
50         }
51
52         $original = @parse_url($requested_url);
53         if ( false === $original )
54                 return;
55
56         // Some PHP setups turn requests for / into /index.php in REQUEST_URI
57         // See: http://trac.wordpress.org/ticket/5017
58         // See: http://trac.wordpress.org/ticket/7173
59         // Disabled, for now:
60         // $original['path'] = preg_replace('|/index\.php$|', '/', $original['path']);
61
62         $redirect = $original;
63         $redirect_url = false;
64
65         // Notice fixing
66         if ( !isset($redirect['path']) )  $redirect['path'] = '';
67         if ( !isset($redirect['query']) ) $redirect['query'] = '';
68
69         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
70
71                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
72
73                 if ( isset($vars[0]) && $vars = $vars[0] ) {
74                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
75                                 $id = $vars->post_parent;
76
77                         if ( $redirect_url = get_permalink($id) )
78                                 $redirect['query'] = remove_query_arg(array('p', 'page_id', 'attachment_id'), $redirect['query']);
79                 }
80         }
81
82         // These tests give us a WP-generated permalink
83         if ( is_404() ) {
84                 $redirect_url = redirect_guess_404_permalink();
85         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
86                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
87                 if ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
88                         if ( $redirect_url = get_permalink(get_query_var('p')) )
89                                 $redirect['query'] = remove_query_arg('p', $redirect['query']);
90                         if ( get_query_var( 'page' ) ) {
91                                 $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
92                                 $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
93                         }
94                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
95                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
96                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
97                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
98                         $m = get_query_var('m');
99                         switch ( strlen($m) ) {
100                                 case 4: // Yearly
101                                         $redirect_url = get_year_link($m);
102                                         break;
103                                 case 6: // Monthly
104                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
105                                         break;
106                                 case 8: // Daily
107                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
108                                         break;
109                         }
110                         if ( $redirect_url )
111                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
112                 // now moving on to non ?m=X year/month/day links
113                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
114                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
115                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
116                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
117                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
118                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
119                 } elseif ( is_year() && !empty($_GET['year']) ) {
120                         if ( $redirect_url = get_year_link(get_query_var('year')) )
121                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
122                 } elseif ( is_category() && !empty($_GET['cat']) && preg_match( '|^[0-9]+$|', $_GET['cat'] ) ) {
123                         if ( $redirect_url = get_category_link(get_query_var('cat')) )
124                                 $redirect['query'] = remove_query_arg('cat', $redirect['query']);
125                 } elseif ( is_author() && !empty($_GET['author']) ) {
126                         $author = get_userdata(get_query_var('author'));
127                         if ( false !== $author && $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
128                                 $redirect['query'] = remove_query_arg('author', $redirect['author']);
129                 }
130
131         // paging and feeds
132                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
133                         if ( !$redirect_url )
134                                 $redirect_url = $requested_url;
135                         $paged_redirect = @parse_url($redirect_url);
136                         while ( preg_match( '#/page/[0-9]+?(/+)?$#', $paged_redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $paged_redirect['path'] ) || preg_match( '#/comment-page-[0-9]+(/+)?$#', $paged_redirect['path'] ) ) {
137                                 // Strip off paging and feed
138                                 $paged_redirect['path'] = preg_replace('#/page/[0-9]+?(/+)?$#', '/', $paged_redirect['path']); // strip off any existing paging
139                                 $paged_redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $paged_redirect['path']); // strip off feed endings
140                                 $paged_redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $paged_redirect['path']); // strip off any existing comment paging
141                         }
142
143                         $addl_path = '';
144                         if ( is_feed() ) {
145                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
146                                 if ( get_query_var( 'withcomments' ) )
147                                         $addl_path .= 'comments/';
148                                 $addl_path .= user_trailingslashit( 'feed/' . ( ( 'rss2' ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
149                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
150                         }
151
152                         if ( get_query_var('paged') > 0 ) {
153                                 $paged = get_query_var('paged');
154                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
155                                 if ( !is_feed() ) {
156                                         if ( $paged > 1 && !is_single() ) {
157                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("page/$paged", 'paged');
158                                         } elseif ( !is_single() ) {
159                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit($paged_redirect['path'], 'paged');
160                                         }
161                                 } elseif ( $paged > 1 ) {
162                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
163                                 }
164                         }
165
166                         if ( get_option('page_comments') && ( ( 'newest' == get_option('default_comments_page') && get_query_var('cpage') > 0 ) || ( 'newest' != get_option('default_comments_page') && get_query_var('cpage') > 1 ) ) ) {
167                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
168                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
169                         }
170
171                         $paged_redirect['path'] = user_trailingslashit( preg_replace('|/index.php/?$|', '/', $paged_redirect['path']) ); // strip off trailing /index.php/
172                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($paged_redirect['path'], '/index.php/') === false )
173                                 $paged_redirect['path'] = trailingslashit($paged_redirect['path']) . 'index.php/';
174                         if ( !empty( $addl_path ) )
175                                 $paged_redirect['path'] = trailingslashit($paged_redirect['path']) . $addl_path;
176                         $redirect_url = $paged_redirect['scheme'] . '://' . $paged_redirect['host'] . $paged_redirect['path'];
177                         $redirect['path'] = $paged_redirect['path'];
178                 }
179         }
180
181         // tack on any additional query vars
182         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
183         if ( $redirect_url && !empty($redirect['query']) ) {
184                 if ( strpos($redirect_url, '?') !== false )
185                         $redirect_url .= '&';
186                 else
187                         $redirect_url .= '?';
188                 $redirect_url .= $redirect['query'];
189         }
190
191         if ( $redirect_url )
192                 $redirect = @parse_url($redirect_url);
193
194         // www.example.com vs example.com
195         $user_home = @parse_url(get_option('home'));
196         if ( !empty($user_home['host']) )
197                 $redirect['host'] = $user_home['host'];
198         if ( empty($user_home['path']) )
199                 $user_home['path'] = '/';
200
201         // Handle ports
202         if ( !empty($user_home['port']) )
203                 $redirect['port'] = $user_home['port'];
204         else
205                 unset($redirect['port']);
206
207         // trailing /index.php
208         $redirect['path'] = preg_replace('|/index.php/*?$|', '/', $redirect['path']);
209
210         // Remove trailing spaces from the path
211         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
212
213         if ( !empty( $redirect['query'] ) ) {
214                 // Remove trailing spaces from certain terminating query string args
215                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
216
217                 // Clean up empty query strings
218                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
219
220                 // Remove redundant leading ampersands
221                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
222         }
223
224         // strip /index.php/ when we're not using PATHINFO permalinks
225         if ( !$wp_rewrite->using_index_permalinks() )
226                 $redirect['path'] = str_replace('/index.php/', '/', $redirect['path']);
227
228         // trailing slashes
229         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
230                 $user_ts_type = '';
231                 if ( get_query_var('paged') > 0 ) {
232                         $user_ts_type = 'paged';
233                 } else {
234                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
235                                 $func = 'is_' . $type;
236                                 if ( call_user_func($func) ) {
237                                         $user_ts_type = $type;
238                                         break;
239                                 }
240                         }
241                 }
242                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
243         } elseif ( is_front_page() ) {
244                 $redirect['path'] = trailingslashit($redirect['path']);
245         }
246
247         // Always trailing slash the Front Page URL
248         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
249                 $redirect['path'] = trailingslashit($redirect['path']);
250
251         // Ignore differences in host capitalization, as this can lead to infinite redirects
252         // Only redirect no-www <=> yes-www
253         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
254                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
255                 $redirect['host'] = $original['host'];
256
257         $compare_original = array($original['host'], $original['path']);
258
259         if ( !empty( $original['port'] ) )
260                 $compare_original[] = $original['port'];
261
262         if ( !empty( $original['query'] ) )
263                 $compare_original[] = $original['query'];
264
265         $compare_redirect = array($redirect['host'], $redirect['path']);
266
267         if ( !empty( $redirect['port'] ) )
268                 $compare_redirect[] = $redirect['port'];
269
270         if ( !empty( $redirect['query'] ) )
271                 $compare_redirect[] = $redirect['query'];
272
273         if ( $compare_original !== $compare_redirect ) {
274                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
275                 if ( !empty($redirect['port']) )
276                         $redirect_url .= ':' . $redirect['port'];
277                 $redirect_url .= $redirect['path'];
278                 if ( !empty($redirect['query']) )
279                         $redirect_url .= '?' . $redirect['query'];
280         }
281
282         if ( !$redirect_url || $redirect_url == $requested_url )
283                 return false;
284
285         // Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning FALSE
286         $redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);
287
288         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
289                 return false;
290
291         if ( $do_redirect ) {
292                 // protect against chained redirects
293                 if ( !redirect_canonical($redirect_url, false) ) {
294                         wp_redirect($redirect_url, 301);
295                         exit();
296                 } else {
297                         // Debug
298                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
299                         return false;
300                 }
301         } else {
302                 return $redirect_url;
303         }
304 }
305
306 /**
307  * Attempts to guess correct post based on query vars.
308  *
309  * @since 2.3.0
310  * @uses $wpdb
311  *
312  * @return bool|string Returns False, if it can't find post, returns correct
313  *              location on success.
314  */
315 function redirect_guess_404_permalink() {
316         global $wpdb;
317
318         if ( !get_query_var('name') )
319                 return false;
320
321         $where = $wpdb->prepare("post_name LIKE %s", get_query_var('name') . '%');
322
323         // if any of year, monthnum, or day are set, use them to refine the query
324         if ( get_query_var('year') )
325                 $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
326         if ( get_query_var('monthnum') )
327                 $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
328         if ( get_query_var('day') )
329                 $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
330
331         $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
332         if ( !$post_id )
333                 return false;
334         return get_permalink($post_id);
335 }
336
337 add_action('template_redirect', 'redirect_canonical');
338
339 ?>