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 ( ! $redirect_url ) {
 105                         if ( $redirect_url = redirect_guess_404_permalink() ) {
 106                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 107                         }
 108                 }
 109
 110         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
 111                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
 112                 if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
 113                         if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
 114                                 $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
 115                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
 116                         if ( $redirect_url = get_permalink(get_query_var('p')) )
 117                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
 118                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
 119                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
 120                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
 121                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
 122                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
 123                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 124                 } elseif ( is_page() && !is_feed() && isset($wp_query->queried_object) && 'page' == get_option('show_on_front') && $wp_query->queried_object->ID == get_option('page_on_front')  && ! $redirect_url ) {
 125                         $redirect_url = home_url('/');
 126                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
 127                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
 128                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 129                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
 130                         $m = get_query_var('m');
 131                         switch ( strlen($m) ) {
 132                                 case 4: // Yearly
 133                                         $redirect_url = get_year_link($m);
 134                                         break;
 135                                 case 6: // Monthly
 136                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
 137                                         break;
 138                                 case 8: // Daily
 139                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
 140                                         break;
 141                         }
 142                         if ( $redirect_url )
 143                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
 144                 // now moving on to non ?m=X year/month/day links
 145                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
 146                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
 147                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
 148                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
 149                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
 150                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
 151                 } elseif ( is_year() && !empty($_GET['year']) ) {
 152                         if ( $redirect_url = get_year_link(get_query_var('year')) )
 153                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
 154                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
 155                         $author = get_userdata(get_query_var('author'));
 156                         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 ) ) ) {
 157                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
 158                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
 159                         }
 160                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
 161
 162                         $term_count = 0;
 163                         foreach ( $wp_query->tax_query->queries as $tax_query )
 164                                 $term_count += count( $tax_query['terms'] );
 165
 166                         $obj = $wp_query->get_queried_object();
 167                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
 168                                 if ( !empty($redirect['query']) ) {
 169                                         // Strip taxonomy query vars off the url.
 170                                         $qv_remove = array( 'term', 'taxonomy');
 171                                         if ( is_category() ) {
 172                                                 $qv_remove[] = 'category_name';
 173                                                 $qv_remove[] = 'cat';
 174                                         } elseif ( is_tag() ) {
 175                                                 $qv_remove[] = 'tag';
 176                                                 $qv_remove[] = 'tag_id';
 177                                         } else { // Custom taxonomies will have a custom query var, remove those too:
 178                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
 179                                                 if ( false !== $tax_obj->query_var )
 180                                                         $qv_remove[] = $tax_obj->query_var;
 181                                         }
 182
 183                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
 184
 185                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
 186                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
 187
 188                                                 // Create the destination url for this taxonomy
 189                                                 $tax_url = parse_url($tax_url);
 190                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
 191                                                         parse_str($tax_url['query'], $query_vars);
 192                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
 193                                                 } else { // Taxonomy is accessible via a "pretty-URL"
 194                                                         $redirect['path'] = $tax_url['path'];
 195                                                 }
 196
 197                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
 198                                                 foreach ( $qv_remove as $_qv ) {
 199                                                         if ( isset($rewrite_vars[$_qv]) )
 200                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
 201                                                 }
 202                                         }
 203                                 }
 204
 205                         }
 206                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
 207                         $category = get_category_by_path( $cat );
 208                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
 209                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
 210                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
 211                 }
 212
 213                 // Post Paging
 214                 if ( is_singular() && ! is_front_page() && get_query_var('page') ) {
 215                         if ( !$redirect_url )
 216                                 $redirect_url = get_permalink( get_queried_object_id() );
 217                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 218                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
 219                 }
 220
 221                 // paging and feeds
 222                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
 223                         while ( preg_match( "#/$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'] ) ) {
 224                                 // Strip off paging and feed
 225                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
 226                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
 227                                 $redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $redirect['path']); // strip off any existing comment paging
 228                         }
 229
 230                         $addl_path = '';
 231                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
 232                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 233                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
 234                                         $addl_path .= 'comments/';
 235                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
 236                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
 237                                 else
 238                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
 239                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
 240                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
 241                                 $old_feed_files = array(
 242                                         'wp-atom.php'         => 'atom',
 243                                         'wp-commentsrss2.php' => 'comments_rss2',
 244                                         'wp-feed.php'         => get_default_feed(),
 245                                         'wp-rdf.php'          => 'rdf',
 246                                         'wp-rss.php'          => 'rss2',
 247                                         'wp-rss2.php'         => 'rss2',
 248                                 );
 249                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
 250                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
 251                                         wp_redirect( $redirect_url, 301 );
 252                                         die();
 253                                 }
 254                         }
 255
 256                         if ( get_query_var('paged') > 0 ) {
 257                                 $paged = get_query_var('paged');
 258                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
 259                                 if ( !is_feed() ) {
 260                                         if ( $paged > 1 && !is_single() ) {
 261                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
 262                                         } elseif ( !is_single() ) {
 263                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 264                                         }
 265                                 } elseif ( $paged > 1 ) {
 266                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
 267                                 }
 268                         }
 269
 270                         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 ) ) ) {
 271                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
 272                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 273                         }
 274
 275                         $redirect['path'] = user_trailingslashit( preg_replace('|/index.php/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
 276                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/index.php/') === false )
 277                                 $redirect['path'] = trailingslashit($redirect['path']) . 'index.php/';
 278                         if ( !empty( $addl_path ) )
 279                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
 280                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
 281                 }
 282
 283                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
 284                         if ( is_multisite() )
 285                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
 286                         else
 287                                 $redirect_url = site_url( 'wp-login.php?action=register' );
 288                         wp_redirect( $redirect_url, 301 );
 289                         die();
 290                 }
 291         }
 292
 293         // tack on any additional query vars
 294         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 295         if ( $redirect_url && !empty($redirect['query']) ) {
 296                 parse_str( $redirect['query'], $_parsed_query );
 297                 $redirect = @parse_url($redirect_url);
 298
 299                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
 300                         parse_str( $redirect['query'], $_parsed_redirect_query );
 301
 302                         if ( empty( $_parsed_redirect_query['name'] ) )
 303                                 unset( $_parsed_query['name'] );
 304                 }
 305
 306                 $_parsed_query = rawurlencode_deep( $_parsed_query );
 307                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
 308         }
 309
 310         if ( $redirect_url )
 311                 $redirect = @parse_url($redirect_url);
 312
 313         // www.example.com vs example.com
 314         $user_home = @parse_url(home_url());
 315         if ( !empty($user_home['host']) )
 316                 $redirect['host'] = $user_home['host'];
 317         if ( empty($user_home['path']) )
 318                 $user_home['path'] = '/';
 319
 320         // Handle ports
 321         if ( !empty($user_home['port']) )
 322                 $redirect['port'] = $user_home['port'];
 323         else
 324                 unset($redirect['port']);
 325
 326         // trailing /index.php
 327         $redirect['path'] = preg_replace('|/index.php/*?$|', '/', $redirect['path']);
 328
 329         // Remove trailing spaces from the path
 330         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
 331
 332         if ( !empty( $redirect['query'] ) ) {
 333                 // Remove trailing spaces from certain terminating query string args
 334                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
 335
 336                 // Clean up empty query strings
 337                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
 338
 339                 // Redirect obsolete feeds
 340                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$3', $redirect['query'] );
 341
 342                 // Remove redundant leading ampersands
 343                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 344         }
 345
 346         // strip /index.php/ when we're not using PATHINFO permalinks
 347         if ( !$wp_rewrite->using_index_permalinks() )
 348                 $redirect['path'] = str_replace('/index.php/', '/', $redirect['path']);
 349
 350         // trailing slashes
 351         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
 352                 $user_ts_type = '';
 353                 if ( get_query_var('paged') > 0 ) {
 354                         $user_ts_type = 'paged';
 355                 } else {
 356                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
 357                                 $func = 'is_' . $type;
 358                                 if ( call_user_func($func) ) {
 359                                         $user_ts_type = $type;
 360                                         break;
 361                                 }
 362                         }
 363                 }
 364                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
 365         } elseif ( is_front_page() ) {
 366                 $redirect['path'] = trailingslashit($redirect['path']);
 367         }
 368
 369         // Strip multiple slashes out of the URL
 370         if ( strpos($redirect['path'], '//') > -1 )
 371                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
 372
 373         // Always trailing slash the Front Page URL
 374         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
 375                 $redirect['path'] = trailingslashit($redirect['path']);
 376
 377         // Ignore differences in host capitalization, as this can lead to infinite redirects
 378         // Only redirect no-www <=> yes-www
 379         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
 380                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
 381                 $redirect['host'] = $original['host'];
 382
 383         $compare_original = array($original['host'], $original['path']);
 384
 385         if ( !empty( $original['port'] ) )
 386                 $compare_original[] = $original['port'];
 387
 388         if ( !empty( $original['query'] ) )
 389                 $compare_original[] = $original['query'];
 390
 391         $compare_redirect = array($redirect['host'], $redirect['path']);
 392
 393         if ( !empty( $redirect['port'] ) )
 394                 $compare_redirect[] = $redirect['port'];
 395
 396         if ( !empty( $redirect['query'] ) )
 397                 $compare_redirect[] = $redirect['query'];
 398
 399         if ( $compare_original !== $compare_redirect ) {
 400                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
 401                 if ( !empty($redirect['port']) )
 402                         $redirect_url .= ':' . $redirect['port'];
 403                 $redirect_url .= $redirect['path'];
 404                 if ( !empty($redirect['query']) )
 405                         $redirect_url .= '?' . $redirect['query'];
 406         }
 407
 408         if ( !$redirect_url || $redirect_url == $requested_url )
 409                 return false;
 410
 411         // Hex encoded octets are case-insensitive.
 412         if ( false !== strpos($requested_url, '%') ) {
 413                 if ( !function_exists('lowercase_octets') ) {
 414                         function lowercase_octets($matches) {
 415                                 return strtolower( $matches[0] );
 416                         }
 417                 }
 418                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
 419         }
 420
 421         // Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning false
 422         $redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);
 423
 424         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
 425                 return false;
 426
 427         if ( $do_redirect ) {
 428                 // protect against chained redirects
 429                 if ( !redirect_canonical($redirect_url, false) ) {
 430                         wp_redirect($redirect_url, 301);
 431                         exit();
 432                 } else {
 433                         // Debug
 434                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
 435                         return false;
 436                 }
 437         } else {
 438                 return $redirect_url;
 439         }
 440 }
 441
 442 /**
 443  * Removes arguments from a query string if they are not present in a URL
 444  * DO NOT use this in plugin code.
 445  *
 446  * @since 3.4
 447  * @access private
 448  *
 449  * @return string The altered query string
 450  */
 451 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
 452         $parsed_url = @parse_url( $url );
 453         if ( ! empty( $parsed_url['query'] ) ) {
 454                 parse_str( $parsed_url['query'], $parsed_query );
 455                 foreach ( $args_to_check as $qv ) {
 456                         if ( !isset( $parsed_query[$qv] ) )
 457                                 $query_string = remove_query_arg( $qv, $query_string );
 458                 }
 459         } else {
 460                 $query_string = remove_query_arg( $args_to_check, $query_string );
 461         }
 462         return $query_string;
 463 }
 464
 465 /**
 466  * Attempts to guess the correct URL based on query vars
 467  *
 468  * @since 2.3.0
 469  * @uses $wpdb
 470  *
 471  * @return bool|string The correct URL if one is found. False on failure.
 472  */
 473 function redirect_guess_404_permalink() {
 474         global $wpdb, $wp_rewrite;
 475
 476         if ( get_query_var('name') ) {
 477                 $where = $wpdb->prepare("post_name LIKE %s", like_escape( get_query_var('name') ) . '%');
 478
 479                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
 480                 if ( get_query_var('post_type') )
 481                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
 482                 else
 483                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
 484
 485                 if ( get_query_var('year') )
 486                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
 487                 if ( get_query_var('monthnum') )
 488                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
 489                 if ( get_query_var('day') )
 490                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
 491
 492                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
 493                 if ( ! $post_id )
 494                         return false;
 495                 if ( get_query_var( 'feed' ) )
 496                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
 497                 elseif ( get_query_var( 'page' ) )
 498                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 499                 else
 500                         return get_permalink( $post_id );
 501         }
 502
 503         return false;
 504 }
 505
 506 add_action('template_redirect', 'redirect_canonical');
 507
 508 function wp_redirect_admin_locations() {
 509         global $wp_rewrite;
 510         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
 511                 return;
 512
 513         $admins = array(
 514                 home_url( 'wp-admin', 'relative' ),
 515                 home_url( 'dashboard', 'relative' ),
 516                 home_url( 'admin', 'relative' ),
 517                 site_url( 'dashboard', 'relative' ),
 518                 site_url( 'admin', 'relative' ),
 519         );
 520         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
 521                 wp_redirect( admin_url() );
 522                 exit;
 523         }
 524
 525         $logins = array(
 526                 home_url( 'wp-login.php', 'relative' ),
 527                 home_url( 'login', 'relative' ),
 528                 site_url( 'login', 'relative' ),
 529         );
 530         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
 531                 wp_redirect( site_url( 'wp-login.php', 'login' ) );
 532                 exit;
 533         }
 534 }
 535
 536 add_action( 'template_redirect', 'wp_redirect_admin_locations', 1000 );