WordPress 4.5
[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, 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  *
31  * @global WP_Rewrite $wp_rewrite
32  * @global bool $is_IIS
33  * @global WP_Query $wp_query
34  * @global wpdb $wpdb WordPress database abstraction object.
35  *
36  * @param string $requested_url Optional. The URL that was requested, used to
37  *              figure if redirect is needed.
38  * @param bool $do_redirect Optional. Redirect to the new URL.
39  * @return string|void The string of the URL, if redirect needed.
40  */
41 function redirect_canonical( $requested_url = null, $do_redirect = true ) {
42         global $wp_rewrite, $is_IIS, $wp_query, $wpdb, $wp;
43
44         if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ) ) ) {
45                 return;
46         }
47
48         // If we're not in wp-admin and the post has been published and preview nonce
49         // is non-existent or invalid then no need for preview in query
50         if ( is_preview() && get_query_var( 'p' ) && 'publish' == get_post_status( get_query_var( 'p' ) ) ) {
51                 if ( ! isset( $_GET['preview_id'] )
52                         || ! isset( $_GET['preview_nonce'] )
53                         || ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] ) ) {
54                         $wp_query->is_preview = false;
55                 }
56         }
57
58         if ( is_trackback() || is_search() || is_admin() || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) ) {
59                 return;
60         }
61
62         if ( ! $requested_url && isset( $_SERVER['HTTP_HOST'] ) ) {
63                 // build the URL in the address bar
64                 $requested_url  = is_ssl() ? 'https://' : 'http://';
65                 $requested_url .= $_SERVER['HTTP_HOST'];
66                 $requested_url .= $_SERVER['REQUEST_URI'];
67         }
68
69         $original = @parse_url($requested_url);
70         if ( false === $original ) {
71                 return;
72         }
73
74         $redirect = $original;
75         $redirect_url = false;
76
77         // Notice fixing
78         if ( !isset($redirect['path']) )
79                 $redirect['path'] = '';
80         if ( !isset($redirect['query']) )
81                 $redirect['query'] = '';
82
83         // If the original URL ended with non-breaking spaces, they were almost
84         // certainly inserted by accident. Let's remove them, so the reader doesn't
85         // see a 404 error with no obvious cause.
86         $redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );
87
88         // It's not a preview, so remove it from URL
89         if ( get_query_var( 'preview' ) ) {
90                 $redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
91         }
92
93         if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
94                 if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
95                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
96                         $redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
97                 }
98         }
99
100         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
101
102                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
103
104                 if ( isset($vars[0]) && $vars = $vars[0] ) {
105                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
106                                 $id = $vars->post_parent;
107
108                         if ( $redirect_url = get_permalink($id) )
109                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
110                 }
111         }
112
113         // These tests give us a WP-generated permalink
114         if ( is_404() ) {
115
116                 // Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
117                 $id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
118                 if ( $id && $redirect_post = get_post($id) ) {
119                         $post_type_obj = get_post_type_object($redirect_post->post_type);
120                         if ( $post_type_obj->public && 'auto-draft' != $redirect_post->post_status ) {
121                                 $redirect_url = get_permalink($redirect_post);
122                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
123                         }
124                 }
125
126                 if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
127                         $year  = get_query_var( 'year' );
128                         $month = get_query_var( 'monthnum' );
129                         $day   = get_query_var( 'day' );
130                         $date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
131                         if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
132                                 $redirect_url = get_month_link( $year, $month );
133                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
134                         }
135                 } elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
136                         $redirect_url = get_year_link( get_query_var( 'year' ) );
137                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
138                 }
139
140                 if ( ! $redirect_url ) {
141                         if ( $redirect_url = redirect_guess_404_permalink() ) {
142                                 $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 );
143                         }
144                 }
145
146                 if ( get_query_var( 'page' ) && $wp_query->post &&
147                         false !== strpos( $wp_query->post->post_content, '<!--nextpage-->' ) ) {
148                         $redirect['path'] = rtrim( $redirect['path'], (int) get_query_var( 'page' ) . '/' );
149                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
150                         $redirect_url = get_permalink( $wp_query->post->ID );
151                 }
152
153         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
154                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
155                 if ( is_attachment() &&
156                         ! array_diff( array_keys( $wp->query_vars ), array( 'attachment', 'attachment_id' ) ) &&
157                         ! $redirect_url ) {
158                         if ( ! empty( $_GET['attachment_id'] ) ) {
159                                 $redirect_url = get_attachment_link( get_query_var( 'attachment_id' ) );
160                                 if ( $redirect_url ) {
161                                         $redirect['query'] = remove_query_arg( 'attachment_id', $redirect['query'] );
162                                 }
163                         } else {
164                                 $redirect_url = get_attachment_link();
165                         }
166                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
167                         if ( $redirect_url = get_permalink(get_query_var('p')) )
168                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
169                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
170                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
171                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
172                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
173                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
174                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
175                 } elseif ( is_page() && !is_feed() && 'page' == get_option('show_on_front') && get_queried_object_id() == get_option('page_on_front')  && ! $redirect_url ) {
176                         $redirect_url = home_url('/');
177                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
178                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
179                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
180                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
181                         $m = get_query_var('m');
182                         switch ( strlen($m) ) {
183                                 case 4: // Yearly
184                                         $redirect_url = get_year_link($m);
185                                         break;
186                                 case 6: // Monthly
187                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
188                                         break;
189                                 case 8: // Daily
190                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
191                                         break;
192                         }
193                         if ( $redirect_url )
194                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
195                 // now moving on to non ?m=X year/month/day links
196                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
197                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
198                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
199                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
200                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
201                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
202                 } elseif ( is_year() && !empty($_GET['year']) ) {
203                         if ( $redirect_url = get_year_link(get_query_var('year')) )
204                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
205                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
206                         $author = get_userdata(get_query_var('author'));
207                         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 ) ) ) {
208                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
209                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
210                         }
211                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
212
213                         $term_count = 0;
214                         foreach ( $wp_query->tax_query->queried_terms as $tax_query )
215                                 $term_count += count( $tax_query['terms'] );
216
217                         $obj = $wp_query->get_queried_object();
218                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
219                                 if ( !empty($redirect['query']) ) {
220                                         // Strip taxonomy query vars off the url.
221                                         $qv_remove = array( 'term', 'taxonomy');
222                                         if ( is_category() ) {
223                                                 $qv_remove[] = 'category_name';
224                                                 $qv_remove[] = 'cat';
225                                         } elseif ( is_tag() ) {
226                                                 $qv_remove[] = 'tag';
227                                                 $qv_remove[] = 'tag_id';
228                                         } else { // Custom taxonomies will have a custom query var, remove those too:
229                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
230                                                 if ( false !== $tax_obj->query_var )
231                                                         $qv_remove[] = $tax_obj->query_var;
232                                         }
233
234                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
235
236                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
237                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
238
239                                                 // Create the destination url for this taxonomy
240                                                 $tax_url = parse_url($tax_url);
241                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
242                                                         parse_str($tax_url['query'], $query_vars);
243                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
244                                                 } else { // Taxonomy is accessible via a "pretty-URL"
245                                                         $redirect['path'] = $tax_url['path'];
246                                                 }
247
248                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
249                                                 foreach ( $qv_remove as $_qv ) {
250                                                         if ( isset($rewrite_vars[$_qv]) )
251                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
252                                                 }
253                                         }
254                                 }
255
256                         }
257                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
258                         $category = get_category_by_path( $cat );
259                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
260                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
261                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
262                 }
263
264                 // Post Paging
265                 if ( is_singular() && get_query_var('page') ) {
266                         if ( !$redirect_url )
267                                 $redirect_url = get_permalink( get_queried_object_id() );
268
269                         $page = get_query_var( 'page' );
270                         if ( $page > 1 ) {
271                                 if ( is_front_page() ) {
272                                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( "$wp_rewrite->pagination_base/$page", 'paged' );
273                                 } else {
274                                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( $page, 'single_paged' );
275                                 }
276                         }
277                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
278                 }
279
280                 // paging and feeds
281                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
282                         while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $redirect['path'] ) || preg_match( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+(/+)?$#", $redirect['path'] ) ) {
283                                 // Strip off paging and feed
284                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
285                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
286                                 $redirect['path'] = preg_replace("#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing comment paging
287                         }
288
289                         $addl_path = '';
290                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
291                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
292                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
293                                         $addl_path .= 'comments/';
294                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
295                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
296                                 else
297                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
298                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
299                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
300                                 $old_feed_files = array(
301                                         'wp-atom.php'         => 'atom',
302                                         'wp-commentsrss2.php' => 'comments_rss2',
303                                         'wp-feed.php'         => get_default_feed(),
304                                         'wp-rdf.php'          => 'rdf',
305                                         'wp-rss.php'          => 'rss2',
306                                         'wp-rss2.php'         => 'rss2',
307                                 );
308                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
309                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
310                                         wp_redirect( $redirect_url, 301 );
311                                         die();
312                                 }
313                         }
314
315                         if ( get_query_var('paged') > 0 ) {
316                                 $paged = get_query_var('paged');
317                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
318                                 if ( !is_feed() ) {
319                                         if ( $paged > 1 && !is_single() ) {
320                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
321                                         } elseif ( !is_single() ) {
322                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
323                                         }
324                                 } elseif ( $paged > 1 ) {
325                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
326                                 }
327                         }
328
329                         if ( get_option( 'page_comments' ) && (
330                                 ( 'newest' == get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 0 ) ||
331                                 ( 'newest' != get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 1 )
332                         ) ) {
333                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . get_query_var('cpage'), 'commentpaged' );
334                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
335                         }
336
337                         $redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
338                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
339                                 $redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
340                         if ( !empty( $addl_path ) )
341                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
342                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
343                 }
344
345                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
346                         if ( is_multisite() ) {
347                                 /** This filter is documented in wp-login.php */
348                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
349                         } else {
350                                 $redirect_url = wp_registration_url();
351                         }
352
353                         wp_redirect( $redirect_url, 301 );
354                         die();
355                 }
356         }
357
358         // tack on any additional query vars
359         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
360         if ( $redirect_url && !empty($redirect['query']) ) {
361                 parse_str( $redirect['query'], $_parsed_query );
362                 $redirect = @parse_url($redirect_url);
363
364                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
365                         parse_str( $redirect['query'], $_parsed_redirect_query );
366
367                         if ( empty( $_parsed_redirect_query['name'] ) )
368                                 unset( $_parsed_query['name'] );
369                 }
370
371                 $_parsed_query = rawurlencode_deep( $_parsed_query );
372                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
373         }
374
375         if ( $redirect_url )
376                 $redirect = @parse_url($redirect_url);
377
378         // www.example.com vs example.com
379         $user_home = @parse_url(home_url());
380         if ( !empty($user_home['host']) )
381                 $redirect['host'] = $user_home['host'];
382         if ( empty($user_home['path']) )
383                 $user_home['path'] = '/';
384
385         // Handle ports
386         if ( !empty($user_home['port']) )
387                 $redirect['port'] = $user_home['port'];
388         else
389                 unset($redirect['port']);
390
391         // trailing /index.php
392         $redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
393
394         // Remove trailing spaces from the path
395         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
396
397         if ( !empty( $redirect['query'] ) ) {
398                 // Remove trailing spaces from certain terminating query string args
399                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
400
401                 // Clean up empty query strings
402                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
403
404                 // Redirect obsolete feeds
405                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
406
407                 // Remove redundant leading ampersands
408                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
409         }
410
411         // strip /index.php/ when we're not using PATHINFO permalinks
412         if ( !$wp_rewrite->using_index_permalinks() )
413                 $redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
414
415         // trailing slashes
416         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
417                 $user_ts_type = '';
418                 if ( get_query_var('paged') > 0 ) {
419                         $user_ts_type = 'paged';
420                 } else {
421                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
422                                 $func = 'is_' . $type;
423                                 if ( call_user_func($func) ) {
424                                         $user_ts_type = $type;
425                                         break;
426                                 }
427                         }
428                 }
429                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
430         } elseif ( is_front_page() ) {
431                 $redirect['path'] = trailingslashit($redirect['path']);
432         }
433
434         // Strip multiple slashes out of the URL
435         if ( strpos($redirect['path'], '//') > -1 )
436                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
437
438         // Always trailing slash the Front Page URL
439         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
440                 $redirect['path'] = trailingslashit($redirect['path']);
441
442         // Ignore differences in host capitalization, as this can lead to infinite redirects
443         // Only redirect no-www <=> yes-www
444         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
445                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
446                 $redirect['host'] = $original['host'];
447
448         $compare_original = array( $original['host'], $original['path'] );
449
450         if ( !empty( $original['port'] ) )
451                 $compare_original[] = $original['port'];
452
453         if ( !empty( $original['query'] ) )
454                 $compare_original[] = $original['query'];
455
456         $compare_redirect = array( $redirect['host'], $redirect['path'] );
457
458         if ( !empty( $redirect['port'] ) )
459                 $compare_redirect[] = $redirect['port'];
460
461         if ( !empty( $redirect['query'] ) )
462                 $compare_redirect[] = $redirect['query'];
463
464         if ( $compare_original !== $compare_redirect ) {
465                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
466                 if ( !empty($redirect['port']) )
467                         $redirect_url .= ':' . $redirect['port'];
468                 $redirect_url .= $redirect['path'];
469                 if ( !empty($redirect['query']) )
470                         $redirect_url .= '?' . $redirect['query'];
471         }
472
473         if ( ! $redirect_url || $redirect_url == $requested_url ) {
474                 return;
475         }
476
477         // Hex encoded octets are case-insensitive.
478         if ( false !== strpos($requested_url, '%') ) {
479                 if ( !function_exists('lowercase_octets') ) {
480                         function lowercase_octets($matches) {
481                                 return strtolower( $matches[0] );
482                         }
483                 }
484                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
485         }
486
487         /**
488          * Filter the canonical redirect URL.
489          *
490          * Returning false to this filter will cancel the redirect.
491          *
492          * @since 2.3.0
493          *
494          * @param string $redirect_url  The redirect URL.
495          * @param string $requested_url The requested URL.
496          */
497         $redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
498
499         // yes, again -- in case the filter aborted the request
500         if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) == strip_fragment_from_url( $requested_url ) ) {
501                 return;
502         }
503
504         if ( $do_redirect ) {
505                 // protect against chained redirects
506                 if ( !redirect_canonical($redirect_url, false) ) {
507                         wp_redirect($redirect_url, 301);
508                         exit();
509                 } else {
510                         // Debug
511                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
512                         return;
513                 }
514         } else {
515                 return $redirect_url;
516         }
517 }
518
519 /**
520  * Removes arguments from a query string if they are not present in a URL
521  * DO NOT use this in plugin code.
522  *
523  * @since 3.4.0
524  * @access private
525  *
526  * @param string $query_string
527  * @param array $args_to_check
528  * @param string $url
529  * @return string The altered query string
530  */
531 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
532         $parsed_url = @parse_url( $url );
533         if ( ! empty( $parsed_url['query'] ) ) {
534                 parse_str( $parsed_url['query'], $parsed_query );
535                 foreach ( $args_to_check as $qv ) {
536                         if ( !isset( $parsed_query[$qv] ) )
537                                 $query_string = remove_query_arg( $qv, $query_string );
538                 }
539         } else {
540                 $query_string = remove_query_arg( $args_to_check, $query_string );
541         }
542         return $query_string;
543 }
544
545 /**
546  * Strips the #fragment from a URL, if one is present.
547  *
548  * @since 4.4.0
549  *
550  * @param string $url The URL to strip.
551  * @return string The altered URL.
552  */
553 function strip_fragment_from_url( $url ) {
554         $parsed_url = @parse_url( $url );
555         if ( ! empty( $parsed_url['host'] ) ) {
556                 // This mirrors code in redirect_canonical(). It does not handle every case.
557                 $url = $parsed_url['scheme'] . '://' . $parsed_url['host'];
558                 if ( ! empty( $parsed_url['port'] ) ) {
559                         $url .= ':' . $parsed_url['port'];
560                 }
561                 $url .= $parsed_url['path'];
562                 if ( ! empty( $parsed_url['query'] ) ) {
563                         $url .= '?' . $parsed_url['query'];
564                 }
565         }
566
567         return $url;
568 }
569
570 /**
571  * Attempts to guess the correct URL based on query vars
572  *
573  * @since 2.3.0
574  *
575  * @global wpdb $wpdb WordPress database abstraction object.
576  *
577  * @return false|string The correct URL if one is found. False on failure.
578  */
579 function redirect_guess_404_permalink() {
580         global $wpdb;
581
582         if ( get_query_var('name') ) {
583                 $where = $wpdb->prepare("post_name LIKE %s", $wpdb->esc_like( get_query_var('name') ) . '%');
584
585                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
586                 if ( get_query_var('post_type') )
587                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
588                 else
589                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
590
591                 if ( get_query_var('year') )
592                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
593                 if ( get_query_var('monthnum') )
594                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
595                 if ( get_query_var('day') )
596                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
597
598                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
599                 if ( ! $post_id )
600                         return false;
601                 if ( get_query_var( 'feed' ) )
602                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
603                 elseif ( get_query_var( 'page' ) && 1 < get_query_var( 'page' ) )
604                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
605                 else
606                         return get_permalink( $post_id );
607         }
608
609         return false;
610 }
611
612 /**
613  * Redirects a variety of shorthand URLs to the admin.
614  *
615  * If a user visits example.com/admin, they'll be redirected to /wp-admin.
616  * Visiting /login redirects to /wp-login.php, and so on.
617  *
618  * @since 3.4.0
619  *
620  * @global WP_Rewrite $wp_rewrite
621  */
622 function wp_redirect_admin_locations() {
623         global $wp_rewrite;
624         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
625                 return;
626
627         $admins = array(
628                 home_url( 'wp-admin', 'relative' ),
629                 home_url( 'dashboard', 'relative' ),
630                 home_url( 'admin', 'relative' ),
631                 site_url( 'dashboard', 'relative' ),
632                 site_url( 'admin', 'relative' ),
633         );
634         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
635                 wp_redirect( admin_url() );
636                 exit;
637         }
638
639         $logins = array(
640                 home_url( 'wp-login.php', 'relative' ),
641                 home_url( 'login', 'relative' ),
642                 site_url( 'login', 'relative' ),
643         );
644         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
645                 wp_redirect( wp_login_url() );
646                 exit;
647         }
648 }