c1b90251cf2fd211e9b0caabffad6f50630465e8
[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 ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ) ) ) {
43                 return;
44         }
45
46         // If we're not in wp-admin and the post has been published and preview nonce
47         // is non-existent or invalid then no need for preview in query
48         if ( is_preview() && get_query_var( 'p' ) && 'publish' == get_post_status( get_query_var( 'p' ) ) ) {
49                 if ( ! isset( $_GET['preview_id'] )
50                         || ! isset( $_GET['preview_nonce'] )
51                         || ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] ) ) {
52                         $wp_query->is_preview = false;
53                 }
54         }
55
56         if ( is_trackback() || is_search() || is_comments_popup() || is_admin() || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) ) {
57                 return;
58         }
59
60         if ( !$requested_url ) {
61                 // build the URL in the address bar
62                 $requested_url  = is_ssl() ? 'https://' : 'http://';
63                 $requested_url .= $_SERVER['HTTP_HOST'];
64                 $requested_url .= $_SERVER['REQUEST_URI'];
65         }
66
67         $original = @parse_url($requested_url);
68         if ( false === $original )
69                 return;
70
71         // Some PHP setups turn requests for / into /index.php in REQUEST_URI
72         // See: http://trac.wordpress.org/ticket/5017
73         // See: http://trac.wordpress.org/ticket/7173
74         // Disabled, for now:
75         // $original['path'] = preg_replace('|/index\.php$|', '/', $original['path']);
76
77         $redirect = $original;
78         $redirect_url = false;
79
80         // Notice fixing
81         if ( !isset($redirect['path']) )
82                 $redirect['path'] = '';
83         if ( !isset($redirect['query']) )
84                 $redirect['query'] = '';
85
86         // It's not a preview, so remove it from URL
87         if ( get_query_var( 'preview' ) ) {
88                 $redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
89         }
90
91         if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
92                 if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
93                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
94                         $redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
95                 }
96         }
97
98         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
99
100                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
101
102                 if ( isset($vars[0]) && $vars = $vars[0] ) {
103                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
104                                 $id = $vars->post_parent;
105
106                         if ( $redirect_url = get_permalink($id) )
107                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
108                 }
109         }
110
111         // These tests give us a WP-generated permalink
112         if ( is_404() ) {
113
114                 // Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
115                 $id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
116                 if ( $id && $redirect_post = get_post($id) ) {
117                         $post_type_obj = get_post_type_object($redirect_post->post_type);
118                         if ( $post_type_obj->public ) {
119                                 $redirect_url = get_permalink($redirect_post);
120                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
121                         }
122                 }
123
124                 if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
125                         $year  = get_query_var( 'year' );
126                         $month = get_query_var( 'monthnum' );
127                         $day   = get_query_var( 'day' );
128                         $date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
129                         if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
130                                 $redirect_url = get_month_link( $year, $month );
131                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
132                         }
133                 } elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
134                         $redirect_url = get_year_link( get_query_var( 'year' ) );
135                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
136                 }
137
138                 if ( ! $redirect_url ) {
139                         if ( $redirect_url = redirect_guess_404_permalink() ) {
140                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
141                         }
142                 }
143
144         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
145                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
146                 if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
147                         if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
148                                 $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
149                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
150                         if ( $redirect_url = get_permalink(get_query_var('p')) )
151                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
152                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
153                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
154                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
155                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
156                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
157                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
158                 } elseif ( is_page() && !is_feed() && isset($wp_query->queried_object) && 'page' == get_option('show_on_front') && $wp_query->queried_object->ID == get_option('page_on_front')  && ! $redirect_url ) {
159                         $redirect_url = home_url('/');
160                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
161                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
162                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
163                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
164                         $m = get_query_var('m');
165                         switch ( strlen($m) ) {
166                                 case 4: // Yearly
167                                         $redirect_url = get_year_link($m);
168                                         break;
169                                 case 6: // Monthly
170                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
171                                         break;
172                                 case 8: // Daily
173                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
174                                         break;
175                         }
176                         if ( $redirect_url )
177                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
178                 // now moving on to non ?m=X year/month/day links
179                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
180                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
181                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
182                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
183                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
184                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
185                 } elseif ( is_year() && !empty($_GET['year']) ) {
186                         if ( $redirect_url = get_year_link(get_query_var('year')) )
187                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
188                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
189                         $author = get_userdata(get_query_var('author'));
190                         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 ) ) ) {
191                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
192                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
193                         }
194                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
195
196                         $term_count = 0;
197                         foreach ( $wp_query->tax_query->queries as $tax_query )
198                                 $term_count += count( $tax_query['terms'] );
199
200                         $obj = $wp_query->get_queried_object();
201                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
202                                 if ( !empty($redirect['query']) ) {
203                                         // Strip taxonomy query vars off the url.
204                                         $qv_remove = array( 'term', 'taxonomy');
205                                         if ( is_category() ) {
206                                                 $qv_remove[] = 'category_name';
207                                                 $qv_remove[] = 'cat';
208                                         } elseif ( is_tag() ) {
209                                                 $qv_remove[] = 'tag';
210                                                 $qv_remove[] = 'tag_id';
211                                         } else { // Custom taxonomies will have a custom query var, remove those too:
212                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
213                                                 if ( false !== $tax_obj->query_var )
214                                                         $qv_remove[] = $tax_obj->query_var;
215                                         }
216
217                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
218
219                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
220                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
221
222                                                 // Create the destination url for this taxonomy
223                                                 $tax_url = parse_url($tax_url);
224                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
225                                                         parse_str($tax_url['query'], $query_vars);
226                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
227                                                 } else { // Taxonomy is accessible via a "pretty-URL"
228                                                         $redirect['path'] = $tax_url['path'];
229                                                 }
230
231                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
232                                                 foreach ( $qv_remove as $_qv ) {
233                                                         if ( isset($rewrite_vars[$_qv]) )
234                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
235                                                 }
236                                         }
237                                 }
238
239                         }
240                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
241                         $category = get_category_by_path( $cat );
242                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
243                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
244                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
245                 }
246
247                 // Post Paging
248                 if ( is_singular() && ! is_front_page() && get_query_var('page') ) {
249                         if ( !$redirect_url )
250                                 $redirect_url = get_permalink( get_queried_object_id() );
251                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
252                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
253                 }
254
255                 // paging and feeds
256                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
257                         while ( preg_match( "#/$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'] ) ) {
258                                 // Strip off paging and feed
259                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
260                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
261                                 $redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $redirect['path']); // strip off any existing comment paging
262                         }
263
264                         $addl_path = '';
265                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
266                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
267                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
268                                         $addl_path .= 'comments/';
269                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
270                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
271                                 else
272                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
273                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
274                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
275                                 $old_feed_files = array(
276                                         'wp-atom.php'         => 'atom',
277                                         'wp-commentsrss2.php' => 'comments_rss2',
278                                         'wp-feed.php'         => get_default_feed(),
279                                         'wp-rdf.php'          => 'rdf',
280                                         'wp-rss.php'          => 'rss2',
281                                         'wp-rss2.php'         => 'rss2',
282                                 );
283                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
284                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
285                                         wp_redirect( $redirect_url, 301 );
286                                         die();
287                                 }
288                         }
289
290                         if ( get_query_var('paged') > 0 ) {
291                                 $paged = get_query_var('paged');
292                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
293                                 if ( !is_feed() ) {
294                                         if ( $paged > 1 && !is_single() ) {
295                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
296                                         } elseif ( !is_single() ) {
297                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
298                                         }
299                                 } elseif ( $paged > 1 ) {
300                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
301                                 }
302                         }
303
304                         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 ) ) ) {
305                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
306                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
307                         }
308
309                         $redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
310                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
311                                 $redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
312                         if ( !empty( $addl_path ) )
313                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
314                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
315                 }
316
317                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
318                         if ( is_multisite() ) {
319                                 /** This filter is documented in wp-login.php */
320                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
321                         } else {
322                                 $redirect_url = site_url( 'wp-login.php?action=register' );
323                         }
324
325                         wp_redirect( $redirect_url, 301 );
326                         die();
327                 }
328         }
329
330         // tack on any additional query vars
331         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
332         if ( $redirect_url && !empty($redirect['query']) ) {
333                 parse_str( $redirect['query'], $_parsed_query );
334                 $redirect = @parse_url($redirect_url);
335
336                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
337                         parse_str( $redirect['query'], $_parsed_redirect_query );
338
339                         if ( empty( $_parsed_redirect_query['name'] ) )
340                                 unset( $_parsed_query['name'] );
341                 }
342
343                 $_parsed_query = rawurlencode_deep( $_parsed_query );
344                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
345         }
346
347         if ( $redirect_url )
348                 $redirect = @parse_url($redirect_url);
349
350         // www.example.com vs example.com
351         $user_home = @parse_url(home_url());
352         if ( !empty($user_home['host']) )
353                 $redirect['host'] = $user_home['host'];
354         if ( empty($user_home['path']) )
355                 $user_home['path'] = '/';
356
357         // Handle ports
358         if ( !empty($user_home['port']) )
359                 $redirect['port'] = $user_home['port'];
360         else
361                 unset($redirect['port']);
362
363         if ( ! empty( $user_home['scheme'] ) && $user_home['scheme'] === 'https' ) {
364                 $redirect['scheme'] = 'https';
365         }
366
367         // trailing /index.php
368         $redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
369
370         // Remove trailing spaces from the path
371         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
372
373         if ( !empty( $redirect['query'] ) ) {
374                 // Remove trailing spaces from certain terminating query string args
375                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
376
377                 // Clean up empty query strings
378                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
379
380                 // Redirect obsolete feeds
381                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
382
383                 // Remove redundant leading ampersands
384                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
385         }
386
387         // strip /index.php/ when we're not using PATHINFO permalinks
388         if ( !$wp_rewrite->using_index_permalinks() )
389                 $redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
390
391         // trailing slashes
392         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
393                 $user_ts_type = '';
394                 if ( get_query_var('paged') > 0 ) {
395                         $user_ts_type = 'paged';
396                 } else {
397                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
398                                 $func = 'is_' . $type;
399                                 if ( call_user_func($func) ) {
400                                         $user_ts_type = $type;
401                                         break;
402                                 }
403                         }
404                 }
405                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
406         } elseif ( is_front_page() ) {
407                 $redirect['path'] = trailingslashit($redirect['path']);
408         }
409
410         // Strip multiple slashes out of the URL
411         if ( strpos($redirect['path'], '//') > -1 )
412                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
413
414         // Always trailing slash the Front Page URL
415         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
416                 $redirect['path'] = trailingslashit($redirect['path']);
417
418         // Ignore differences in host capitalization, as this can lead to infinite redirects
419         // Only redirect no-www <=> yes-www
420         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
421                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
422                 $redirect['host'] = $original['host'];
423
424         $compare_original = array( $original['scheme'], $original['host'], $original['path'] );
425
426         if ( !empty( $original['port'] ) )
427                 $compare_original[] = $original['port'];
428
429         if ( !empty( $original['query'] ) )
430                 $compare_original[] = $original['query'];
431
432         $compare_redirect = array( $redirect['scheme'], $redirect['host'], $redirect['path'] );
433
434         if ( !empty( $redirect['port'] ) )
435                 $compare_redirect[] = $redirect['port'];
436
437         if ( !empty( $redirect['query'] ) )
438                 $compare_redirect[] = $redirect['query'];
439
440         if ( $compare_original !== $compare_redirect ) {
441                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
442                 if ( !empty($redirect['port']) )
443                         $redirect_url .= ':' . $redirect['port'];
444                 $redirect_url .= $redirect['path'];
445                 if ( !empty($redirect['query']) )
446                         $redirect_url .= '?' . $redirect['query'];
447         }
448
449         if ( !$redirect_url || $redirect_url == $requested_url )
450                 return false;
451
452         // Hex encoded octets are case-insensitive.
453         if ( false !== strpos($requested_url, '%') ) {
454                 if ( !function_exists('lowercase_octets') ) {
455                         function lowercase_octets($matches) {
456                                 return strtolower( $matches[0] );
457                         }
458                 }
459                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
460         }
461
462         /**
463          * Filter the canonical redirect URL.
464          *
465          * Returning false to this filter will cancel the redirect.
466          *
467          * @since 2.3.0
468          *
469          * @param string $redirect_url  The redirect URL.
470          * @param string $requested_url The requested URL.
471          */
472         $redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
473
474         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
475                 return false;
476
477         if ( $do_redirect ) {
478                 // protect against chained redirects
479                 if ( !redirect_canonical($redirect_url, false) ) {
480                         wp_redirect($redirect_url, 301);
481                         exit();
482                 } else {
483                         // Debug
484                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
485                         return false;
486                 }
487         } else {
488                 return $redirect_url;
489         }
490 }
491
492 /**
493  * Removes arguments from a query string if they are not present in a URL
494  * DO NOT use this in plugin code.
495  *
496  * @since 3.4.0
497  * @access private
498  *
499  * @return string The altered query string
500  */
501 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
502         $parsed_url = @parse_url( $url );
503         if ( ! empty( $parsed_url['query'] ) ) {
504                 parse_str( $parsed_url['query'], $parsed_query );
505                 foreach ( $args_to_check as $qv ) {
506                         if ( !isset( $parsed_query[$qv] ) )
507                                 $query_string = remove_query_arg( $qv, $query_string );
508                 }
509         } else {
510                 $query_string = remove_query_arg( $args_to_check, $query_string );
511         }
512         return $query_string;
513 }
514
515 /**
516  * Attempts to guess the correct URL based on query vars
517  *
518  * @since 2.3.0
519  * @uses $wpdb
520  *
521  * @return bool|string The correct URL if one is found. False on failure.
522  */
523 function redirect_guess_404_permalink() {
524         global $wpdb, $wp_rewrite;
525
526         if ( get_query_var('name') ) {
527                 $where = $wpdb->prepare("post_name LIKE %s", $wpdb->esc_like( get_query_var('name') ) . '%');
528
529                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
530                 if ( get_query_var('post_type') )
531                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
532                 else
533                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
534
535                 if ( get_query_var('year') )
536                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
537                 if ( get_query_var('monthnum') )
538                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
539                 if ( get_query_var('day') )
540                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
541
542                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
543                 if ( ! $post_id )
544                         return false;
545                 if ( get_query_var( 'feed' ) )
546                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
547                 elseif ( get_query_var( 'page' ) )
548                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
549                 else
550                         return get_permalink( $post_id );
551         }
552
553         return false;
554 }
555
556 add_action('template_redirect', 'redirect_canonical');
557
558 function wp_redirect_admin_locations() {
559         global $wp_rewrite;
560         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
561                 return;
562
563         $admins = array(
564                 home_url( 'wp-admin', 'relative' ),
565                 home_url( 'dashboard', 'relative' ),
566                 home_url( 'admin', 'relative' ),
567                 site_url( 'dashboard', 'relative' ),
568                 site_url( 'admin', 'relative' ),
569         );
570         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
571                 wp_redirect( admin_url() );
572                 exit;
573         }
574
575         $logins = array(
576                 home_url( 'wp-login.php', 'relative' ),
577                 home_url( 'login', 'relative' ),
578                 site_url( 'login', 'relative' ),
579         );
580         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
581                 wp_redirect( site_url( 'wp-login.php', 'login' ) );
582                 exit;
583         }
584 }
585
586 add_action( 'template_redirect', 'wp_redirect_admin_locations', 1000 );