Wordpress 3.7
[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  * @package WordPress
9  * @since 2.3.0
10  */
11
12 /**
13  * Redirects incoming links to the proper URL based on the site url.
14  *
15  * Search engines consider www.somedomain.com and somedomain.com to be two
16  * different URLs when they both go to the same location. This SEO enhancement
17  * prevents penalty for duplicate content by redirecting all incoming links to
18  * one or the other.
19  *
20  * Prevents redirection for feeds, trackbacks, searches, comment popup, and
21  * admin URLs. Does not redirect on non-pretty-permalink-supporting IIS 7+,
22  * page/post previews, WP admin, Trackbacks, robots.txt, searches, or on POST
23  * requests.
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, $wpdb;
41
42         if ( is_trackback() || is_search() || is_comments_popup() || is_admin() || !empty($_POST) || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) )
43                 return;
44
45         if ( !$requested_url ) {
46                 // build the URL in the address bar
47                 $requested_url  = is_ssl() ? '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']) )
67                 $redirect['path'] = '';
68         if ( !isset($redirect['query']) )
69                 $redirect['query'] = '';
70
71         if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
72                 if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
73                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
74                         $redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
75                 }
76         }
77
78         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
79
80                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
81
82                 if ( isset($vars[0]) && $vars = $vars[0] ) {
83                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
84                                 $id = $vars->post_parent;
85
86                         if ( $redirect_url = get_permalink($id) )
87                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
88                 }
89         }
90
91         // These tests give us a WP-generated permalink
92         if ( is_404() ) {
93
94                 // Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
95                 $id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
96                 if ( $id && $redirect_post = get_post($id) ) {
97                         $post_type_obj = get_post_type_object($redirect_post->post_type);
98                         if ( $post_type_obj->public ) {
99                                 $redirect_url = get_permalink($redirect_post);
100                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
101                         }
102                 }
103
104                 if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
105                         $year  = get_query_var( 'year' );
106                         $month = get_query_var( 'monthnum' );
107                         $day   = get_query_var( 'day' );
108                         $date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
109                         if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
110                                 $redirect_url = get_month_link( $year, $month );
111                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
112                         }
113                 } elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
114                         $redirect_url = get_year_link( get_query_var( 'year' ) );
115                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
116                 }
117
118                 if ( ! $redirect_url ) {
119                         if ( $redirect_url = redirect_guess_404_permalink() ) {
120                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
121                         }
122                 }
123
124         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
125                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
126                 if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
127                         if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
128                                 $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
129                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
130                         if ( $redirect_url = get_permalink(get_query_var('p')) )
131                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
132                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
133                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
134                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
135                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
136                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
137                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
138                 } elseif ( is_page() && !is_feed() && isset($wp_query->queried_object) && 'page' == get_option('show_on_front') && $wp_query->queried_object->ID == get_option('page_on_front')  && ! $redirect_url ) {
139                         $redirect_url = home_url('/');
140                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
141                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
142                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
143                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
144                         $m = get_query_var('m');
145                         switch ( strlen($m) ) {
146                                 case 4: // Yearly
147                                         $redirect_url = get_year_link($m);
148                                         break;
149                                 case 6: // Monthly
150                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
151                                         break;
152                                 case 8: // Daily
153                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
154                                         break;
155                         }
156                         if ( $redirect_url )
157                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
158                 // now moving on to non ?m=X year/month/day links
159                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
160                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
161                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
162                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
163                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
164                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
165                 } elseif ( is_year() && !empty($_GET['year']) ) {
166                         if ( $redirect_url = get_year_link(get_query_var('year')) )
167                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
168                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
169                         $author = get_userdata(get_query_var('author'));
170                         if ( ( false !== $author ) && $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE $wpdb->posts.post_author = %d AND $wpdb->posts.post_status = 'publish' LIMIT 1", $author->ID ) ) ) {
171                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
172                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
173                         }
174                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
175
176                         $term_count = 0;
177                         foreach ( $wp_query->tax_query->queries as $tax_query )
178                                 $term_count += count( $tax_query['terms'] );
179
180                         $obj = $wp_query->get_queried_object();
181                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
182                                 if ( !empty($redirect['query']) ) {
183                                         // Strip taxonomy query vars off the url.
184                                         $qv_remove = array( 'term', 'taxonomy');
185                                         if ( is_category() ) {
186                                                 $qv_remove[] = 'category_name';
187                                                 $qv_remove[] = 'cat';
188                                         } elseif ( is_tag() ) {
189                                                 $qv_remove[] = 'tag';
190                                                 $qv_remove[] = 'tag_id';
191                                         } else { // Custom taxonomies will have a custom query var, remove those too:
192                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
193                                                 if ( false !== $tax_obj->query_var )
194                                                         $qv_remove[] = $tax_obj->query_var;
195                                         }
196
197                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
198
199                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
200                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
201
202                                                 // Create the destination url for this taxonomy
203                                                 $tax_url = parse_url($tax_url);
204                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
205                                                         parse_str($tax_url['query'], $query_vars);
206                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
207                                                 } else { // Taxonomy is accessible via a "pretty-URL"
208                                                         $redirect['path'] = $tax_url['path'];
209                                                 }
210
211                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
212                                                 foreach ( $qv_remove as $_qv ) {
213                                                         if ( isset($rewrite_vars[$_qv]) )
214                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
215                                                 }
216                                         }
217                                 }
218
219                         }
220                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
221                         $category = get_category_by_path( $cat );
222                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
223                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
224                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
225                 }
226
227                 // Post Paging
228                 if ( is_singular() && ! is_front_page() && get_query_var('page') ) {
229                         if ( !$redirect_url )
230                                 $redirect_url = get_permalink( get_queried_object_id() );
231                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
232                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
233                 }
234
235                 // paging and feeds
236                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
237                         while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $redirect['path'] ) || preg_match( '#/comment-page-[0-9]+(/+)?$#', $redirect['path'] ) ) {
238                                 // Strip off paging and feed
239                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
240                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
241                                 $redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $redirect['path']); // strip off any existing comment paging
242                         }
243
244                         $addl_path = '';
245                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
246                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
247                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
248                                         $addl_path .= 'comments/';
249                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
250                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
251                                 else
252                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
253                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
254                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
255                                 $old_feed_files = array(
256                                         'wp-atom.php'         => 'atom',
257                                         'wp-commentsrss2.php' => 'comments_rss2',
258                                         'wp-feed.php'         => get_default_feed(),
259                                         'wp-rdf.php'          => 'rdf',
260                                         'wp-rss.php'          => 'rss2',
261                                         'wp-rss2.php'         => 'rss2',
262                                 );
263                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
264                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
265                                         wp_redirect( $redirect_url, 301 );
266                                         die();
267                                 }
268                         }
269
270                         if ( get_query_var('paged') > 0 ) {
271                                 $paged = get_query_var('paged');
272                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
273                                 if ( !is_feed() ) {
274                                         if ( $paged > 1 && !is_single() ) {
275                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
276                                         } elseif ( !is_single() ) {
277                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
278                                         }
279                                 } elseif ( $paged > 1 ) {
280                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
281                                 }
282                         }
283
284                         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 ) ) ) {
285                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
286                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
287                         }
288
289                         $redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
290                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
291                                 $redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
292                         if ( !empty( $addl_path ) )
293                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
294                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
295                 }
296
297                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
298                         if ( is_multisite() )
299                                 /** This filter is documented in wp-login.php */
300                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
301                         else
302                                 $redirect_url = site_url( 'wp-login.php?action=register' );
303                         wp_redirect( $redirect_url, 301 );
304                         die();
305                 }
306         }
307
308         // tack on any additional query vars
309         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
310         if ( $redirect_url && !empty($redirect['query']) ) {
311                 parse_str( $redirect['query'], $_parsed_query );
312                 $redirect = @parse_url($redirect_url);
313
314                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
315                         parse_str( $redirect['query'], $_parsed_redirect_query );
316
317                         if ( empty( $_parsed_redirect_query['name'] ) )
318                                 unset( $_parsed_query['name'] );
319                 }
320
321                 $_parsed_query = rawurlencode_deep( $_parsed_query );
322                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
323         }
324
325         if ( $redirect_url )
326                 $redirect = @parse_url($redirect_url);
327
328         // www.example.com vs example.com
329         $user_home = @parse_url(home_url());
330         if ( !empty($user_home['host']) )
331                 $redirect['host'] = $user_home['host'];
332         if ( empty($user_home['path']) )
333                 $user_home['path'] = '/';
334
335         // Handle ports
336         if ( !empty($user_home['port']) )
337                 $redirect['port'] = $user_home['port'];
338         else
339                 unset($redirect['port']);
340
341         // trailing /index.php
342         $redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
343
344         // Remove trailing spaces from the path
345         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
346
347         if ( !empty( $redirect['query'] ) ) {
348                 // Remove trailing spaces from certain terminating query string args
349                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
350
351                 // Clean up empty query strings
352                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
353
354                 // Redirect obsolete feeds
355                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
356
357                 // Remove redundant leading ampersands
358                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
359         }
360
361         // strip /index.php/ when we're not using PATHINFO permalinks
362         if ( !$wp_rewrite->using_index_permalinks() )
363                 $redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
364
365         // trailing slashes
366         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
367                 $user_ts_type = '';
368                 if ( get_query_var('paged') > 0 ) {
369                         $user_ts_type = 'paged';
370                 } else {
371                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
372                                 $func = 'is_' . $type;
373                                 if ( call_user_func($func) ) {
374                                         $user_ts_type = $type;
375                                         break;
376                                 }
377                         }
378                 }
379                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
380         } elseif ( is_front_page() ) {
381                 $redirect['path'] = trailingslashit($redirect['path']);
382         }
383
384         // Strip multiple slashes out of the URL
385         if ( strpos($redirect['path'], '//') > -1 )
386                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
387
388         // Always trailing slash the Front Page URL
389         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
390                 $redirect['path'] = trailingslashit($redirect['path']);
391
392         // Ignore differences in host capitalization, as this can lead to infinite redirects
393         // Only redirect no-www <=> yes-www
394         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
395                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
396                 $redirect['host'] = $original['host'];
397
398         $compare_original = array($original['host'], $original['path']);
399
400         if ( !empty( $original['port'] ) )
401                 $compare_original[] = $original['port'];
402
403         if ( !empty( $original['query'] ) )
404                 $compare_original[] = $original['query'];
405
406         $compare_redirect = array($redirect['host'], $redirect['path']);
407
408         if ( !empty( $redirect['port'] ) )
409                 $compare_redirect[] = $redirect['port'];
410
411         if ( !empty( $redirect['query'] ) )
412                 $compare_redirect[] = $redirect['query'];
413
414         if ( $compare_original !== $compare_redirect ) {
415                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
416                 if ( !empty($redirect['port']) )
417                         $redirect_url .= ':' . $redirect['port'];
418                 $redirect_url .= $redirect['path'];
419                 if ( !empty($redirect['query']) )
420                         $redirect_url .= '?' . $redirect['query'];
421         }
422
423         if ( !$redirect_url || $redirect_url == $requested_url )
424                 return false;
425
426         // Hex encoded octets are case-insensitive.
427         if ( false !== strpos($requested_url, '%') ) {
428                 if ( !function_exists('lowercase_octets') ) {
429                         function lowercase_octets($matches) {
430                                 return strtolower( $matches[0] );
431                         }
432                 }
433                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
434         }
435
436         /**
437          * Filter the canonical redirect URL.
438          *
439          * Returning false to this filter will cancel the redirect.
440          *
441          * @since 2.3.0
442          *
443          * @param string $redirect_url  The redirect URL.
444          * @param string $requested_url The requested URL.
445          */
446         $redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
447
448         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
449                 return false;
450
451         if ( $do_redirect ) {
452                 // protect against chained redirects
453                 if ( !redirect_canonical($redirect_url, false) ) {
454                         wp_redirect($redirect_url, 301);
455                         exit();
456                 } else {
457                         // Debug
458                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
459                         return false;
460                 }
461         } else {
462                 return $redirect_url;
463         }
464 }
465
466 /**
467  * Removes arguments from a query string if they are not present in a URL
468  * DO NOT use this in plugin code.
469  *
470  * @since 3.4
471  * @access private
472  *
473  * @return string The altered query string
474  */
475 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
476         $parsed_url = @parse_url( $url );
477         if ( ! empty( $parsed_url['query'] ) ) {
478                 parse_str( $parsed_url['query'], $parsed_query );
479                 foreach ( $args_to_check as $qv ) {
480                         if ( !isset( $parsed_query[$qv] ) )
481                                 $query_string = remove_query_arg( $qv, $query_string );
482                 }
483         } else {
484                 $query_string = remove_query_arg( $args_to_check, $query_string );
485         }
486         return $query_string;
487 }
488
489 /**
490  * Attempts to guess the correct URL based on query vars
491  *
492  * @since 2.3.0
493  * @uses $wpdb
494  *
495  * @return bool|string The correct URL if one is found. False on failure.
496  */
497 function redirect_guess_404_permalink() {
498         global $wpdb, $wp_rewrite;
499
500         if ( get_query_var('name') ) {
501                 $where = $wpdb->prepare("post_name LIKE %s", like_escape( get_query_var('name') ) . '%');
502
503                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
504                 if ( get_query_var('post_type') )
505                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
506                 else
507                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
508
509                 if ( get_query_var('year') )
510                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
511                 if ( get_query_var('monthnum') )
512                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
513                 if ( get_query_var('day') )
514                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
515
516                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
517                 if ( ! $post_id )
518                         return false;
519                 if ( get_query_var( 'feed' ) )
520                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
521                 elseif ( get_query_var( 'page' ) )
522                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
523                 else
524                         return get_permalink( $post_id );
525         }
526
527         return false;
528 }
529
530 add_action('template_redirect', 'redirect_canonical');
531
532 function wp_redirect_admin_locations() {
533         global $wp_rewrite;
534         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
535                 return;
536
537         $admins = array(
538                 home_url( 'wp-admin', 'relative' ),
539                 home_url( 'dashboard', 'relative' ),
540                 home_url( 'admin', 'relative' ),
541                 site_url( 'dashboard', 'relative' ),
542                 site_url( 'admin', 'relative' ),
543         );
544         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
545                 wp_redirect( admin_url() );
546                 exit;
547         }
548
549         $logins = array(
550                 home_url( 'wp-login.php', 'relative' ),
551                 home_url( 'login', 'relative' ),
552                 site_url( 'login', 'relative' ),
553         );
554         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
555                 wp_redirect( site_url( 'wp-login.php', 'login' ) );
556                 exit;
557         }
558 }
559
560 add_action( 'template_redirect', 'wp_redirect_admin_locations', 1000 );