wp-includes/canonical.php

   1 <?php
   2 /**
   3  * Canonical API to handle WordPress Redirecting
   4  *
   5  * Based on "Permalink Redirect" from Scott Yang and "Enforce www. Preference"
   6  * by Mark Jaquith
   7  *
   8  * @package WordPress
   9  * @since 2.3.0
  10  */
  11
  12 /**
  13  * Redirects incoming links to the proper URL based on the site url.
  14  *
  15  * Search engines consider www.somedomain.com and somedomain.com to be two
  16  * different URLs when they both go to the same location. This SEO enhancement
  17  * prevents penalty for duplicate content by redirecting all incoming links to
  18  * one or the other.
  19  *
  20  * Prevents redirection for feeds, trackbacks, searches, comment popup, and
  21  * admin URLs. Does not redirect on non-pretty-permalink-supporting IIS 7+,
  22  * page/post previews, WP admin, Trackbacks, robots.txt, searches, or on POST
  23  * requests.
  24  *
  25  * Will also attempt to find the correct link when a user enters a URL that does
  26  * not exist based on exact WordPress query. Will instead try to parse the URL
  27  * or query in an attempt to figure the correct page to go to.
  28  *
  29  * @since 2.3.0
  30  * @uses $wp_rewrite
  31  * @uses $is_IIS
  32  *
  33  * @param string $requested_url Optional. The URL that was requested, used to
  34  *              figure if redirect is needed.
  35  * @param bool $do_redirect Optional. Redirect to the new URL.
  36  * @return null|false|string Null, if redirect not needed. False, if redirect
  37  *              not needed or the string of the URL
  38  */
  39 function redirect_canonical( $requested_url = null, $do_redirect = true ) {
  40         global $wp_rewrite, $is_IIS, $wp_query, $wpdb;
  41
  42         if ( is_trackback() || is_search() || is_comments_popup() || is_admin() || !empty($_POST) || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) )
  43                 return;
  44
  45         if ( !$requested_url ) {
  46                 // build the URL in the address bar
  47                 $requested_url  = is_ssl() ? 'https://' : 'http://';
  48                 $requested_url .= $_SERVER['HTTP_HOST'];
  49                 $requested_url .= $_SERVER['REQUEST_URI'];
  50         }
  51
  52         $original = @parse_url($requested_url);
  53         if ( false === $original )
  54                 return;
  55
  56         // Some PHP setups turn requests for / into /index.php in REQUEST_URI
  57         // See: http://trac.wordpress.org/ticket/5017
  58         // See: http://trac.wordpress.org/ticket/7173
  59         // Disabled, for now:
  60         // $original['path'] = preg_replace('|/index\.php$|', '/', $original['path']);
  61
  62         $redirect = $original;
  63         $redirect_url = false;
  64
  65         // Notice fixing
  66         if ( !isset($redirect['path']) )
  67                 $redirect['path'] = '';
  68         if ( !isset($redirect['query']) )
  69                 $redirect['query'] = '';
  70
  71         if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
  72                 if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
  73                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
  74                         $redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
  75                 }
  76         }
  77
  78         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
  79
  80                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
  81
  82                 if ( isset($vars[0]) && $vars = $vars[0] ) {
  83                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
  84                                 $id = $vars->post_parent;
  85
  86                         if ( $redirect_url = get_permalink($id) )
  87                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
  88                 }
  89         }
  90
  91         // These tests give us a WP-generated permalink
  92         if ( is_404() ) {
  93
  94                 // Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
  95                 $id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
  96                 if ( $id && $redirect_post = get_post($id) ) {
  97                         $post_type_obj = get_post_type_object($redirect_post->post_type);
  98                         if ( $post_type_obj->public ) {
  99                                 $redirect_url = get_permalink($redirect_post);
 100                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 101                         }
 102                 }
 103
 104                 if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
 105                         $year  = get_query_var( 'year' );
 106                         $month = get_query_var( 'monthnum' );
 107                         $day   = get_query_var( 'day' );
 108                         $date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
 109                         if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
 110                                 $redirect_url = get_month_link( $year, $month );
 111                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
 112                         }
 113                 } elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
 114                         $redirect_url = get_year_link( get_query_var( 'year' ) );
 115                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
 116                 }
 117
 118                 if ( ! $redirect_url ) {
 119                         if ( $redirect_url = redirect_guess_404_permalink() ) {
 120                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 121                         }
 122                 }
 123
 124         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
 125                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
 126                 if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
 127                         if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
 128                                 $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
 129                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
 130                         if ( $redirect_url = get_permalink(get_query_var('p')) )
 131                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
 132                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
 133                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
 134                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
 135                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
 136                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
 137                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 138                 } elseif ( is_page() && !is_feed() && isset($wp_query->queried_object) && 'page' == get_option('show_on_front') && $wp_query->queried_object->ID == get_option('page_on_front')  && ! $redirect_url ) {
 139                         $redirect_url = home_url('/');
 140                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
 141                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
 142                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 143                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
 144                         $m = get_query_var('m');
 145                         switch ( strlen($m) ) {
 146                                 case 4: // Yearly
 147                                         $redirect_url = get_year_link($m);
 148                                         break;
 149                                 case 6: // Monthly
 150                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
 151                                         break;
 152                                 case 8: // Daily
 153                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
 154                                         break;
 155                         }
 156                         if ( $redirect_url )
 157                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
 158                 // now moving on to non ?m=X year/month/day links
 159                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
 160                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
 161                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
 162                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
 163                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
 164                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
 165                 } elseif ( is_year() && !empty($_GET['year']) ) {
 166                         if ( $redirect_url = get_year_link(get_query_var('year')) )
 167                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
 168                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
 169                         $author = get_userdata(get_query_var('author'));
 170                         if ( ( false !== $author ) && $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE $wpdb->posts.post_author = %d AND $wpdb->posts.post_status = 'publish' LIMIT 1", $author->ID ) ) ) {
 171                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
 172                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
 173                         }
 174                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
 175
 176                         $term_count = 0;
 177                         foreach ( $wp_query->tax_query->queries as $tax_query )
 178                                 $term_count += count( $tax_query['terms'] );
 179
 180                         $obj = $wp_query->get_queried_object();
 181                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
 182                                 if ( !empty($redirect['query']) ) {
 183                                         // Strip taxonomy query vars off the url.
 184                                         $qv_remove = array( 'term', 'taxonomy');
 185                                         if ( is_category() ) {
 186                                                 $qv_remove[] = 'category_name';
 187                                                 $qv_remove[] = 'cat';
 188                                         } elseif ( is_tag() ) {
 189                                                 $qv_remove[] = 'tag';
 190                                                 $qv_remove[] = 'tag_id';
 191                                         } else { // Custom taxonomies will have a custom query var, remove those too:
 192                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
 193                                                 if ( false !== $tax_obj->query_var )
 194                                                         $qv_remove[] = $tax_obj->query_var;
 195                                         }
 196
 197                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
 198
 199                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
 200                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
 201
 202                                                 // Create the destination url for this taxonomy
 203                                                 $tax_url = parse_url($tax_url);
 204                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
 205                                                         parse_str($tax_url['query'], $query_vars);
 206                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
 207                                                 } else { // Taxonomy is accessible via a "pretty-URL"
 208                                                         $redirect['path'] = $tax_url['path'];
 209                                                 }
 210
 211                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
 212                                                 foreach ( $qv_remove as $_qv ) {
 213                                                         if ( isset($rewrite_vars[$_qv]) )
 214                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
 215                                                 }
 216                                         }
 217                                 }
 218
 219                         }
 220                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
 221                         $category = get_category_by_path( $cat );
 222                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
 223                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
 224                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
 225                 }
 226
 227                 // Post Paging
 228                 if ( is_singular() && ! is_front_page() && get_query_var('page') ) {
 229                         if ( !$redirect_url )
 230                                 $redirect_url = get_permalink( get_queried_object_id() );
 231                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 232                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
 233                 }
 234
 235                 // paging and feeds
 236                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
 237                         while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $redirect['path'] ) || preg_match( '#/comment-page-[0-9]+(/+)?$#', $redirect['path'] ) ) {
 238                                 // Strip off paging and feed
 239                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
 240                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
 241                                 $redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $redirect['path']); // strip off any existing comment paging
 242                         }
 243
 244                         $addl_path = '';
 245                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
 246                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 247                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
 248                                         $addl_path .= 'comments/';
 249                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
 250                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
 251                                 else
 252                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
 253                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
 254                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
 255                                 $old_feed_files = array(
 256                                         'wp-atom.php'         => 'atom',
 257                                         'wp-commentsrss2.php' => 'comments_rss2',
 258                                         'wp-feed.php'         => get_default_feed(),
 259                                         'wp-rdf.php'          => 'rdf',
 260                                         'wp-rss.php'          => 'rss2',
 261                                         'wp-rss2.php'         => 'rss2',
 262                                 );
 263                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
 264                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
 265                                         wp_redirect( $redirect_url, 301 );
 266                                         die();
 267                                 }
 268                         }
 269
 270                         if ( get_query_var('paged') > 0 ) {
 271                                 $paged = get_query_var('paged');
 272                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
 273                                 if ( !is_feed() ) {
 274                                         if ( $paged > 1 && !is_single() ) {
 275                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
 276                                         } elseif ( !is_single() ) {
 277                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 278                                         }
 279                                 } elseif ( $paged > 1 ) {
 280                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
 281                                 }
 282                         }
 283
 284                         if ( get_option('page_comments') && ( ( 'newest' == get_option('default_comments_page') && get_query_var('cpage') > 0 ) || ( 'newest' != get_option('default_comments_page') && get_query_var('cpage') > 1 ) ) ) {
 285                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
 286                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 287                         }
 288
 289                         $redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
 290                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
 291                                 $redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
 292                         if ( !empty( $addl_path ) )
 293                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
 294                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
 295                 }
 296
 297                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
 298                         if ( is_multisite() )
 299                                 /** This filter is documented in wp-login.php */
 300                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
 301                         else
 302                                 $redirect_url = site_url( 'wp-login.php?action=register' );
 303                         wp_redirect( $redirect_url, 301 );
 304                         die();
 305                 }
 306         }
 307
 308         // tack on any additional query vars
 309         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 310         if ( $redirect_url && !empty($redirect['query']) ) {
 311                 parse_str( $redirect['query'], $_parsed_query );
 312                 $redirect = @parse_url($redirect_url);
 313
 314                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
 315                         parse_str( $redirect['query'], $_parsed_redirect_query );
 316
 317                         if ( empty( $_parsed_redirect_query['name'] ) )
 318                                 unset( $_parsed_query['name'] );
 319                 }
 320
 321                 $_parsed_query = rawurlencode_deep( $_parsed_query );
 322                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
 323         }
 324
 325         if ( $redirect_url )
 326                 $redirect = @parse_url($redirect_url);
 327
 328         // www.example.com vs example.com
 329         $user_home = @parse_url(home_url());
 330         if ( !empty($user_home['host']) )
 331                 $redirect['host'] = $user_home['host'];
 332         if ( empty($user_home['path']) )
 333                 $user_home['path'] = '/';
 334
 335         // Handle ports
 336         if ( !empty($user_home['port']) )
 337                 $redirect['port'] = $user_home['port'];
 338         else
 339                 unset($redirect['port']);
 340
 341         // trailing /index.php
 342         $redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
 343
 344         // Remove trailing spaces from the path
 345         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
 346
 347         if ( !empty( $redirect['query'] ) ) {
 348                 // Remove trailing spaces from certain terminating query string args
 349                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
 350
 351                 // Clean up empty query strings
 352                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
 353
 354                 // Redirect obsolete feeds
 355                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
 356
 357                 // Remove redundant leading ampersands
 358                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 359         }
 360
 361         // strip /index.php/ when we're not using PATHINFO permalinks
 362         if ( !$wp_rewrite->using_index_permalinks() )
 363                 $redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
 364
 365         // trailing slashes
 366         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
 367                 $user_ts_type = '';
 368                 if ( get_query_var('paged') > 0 ) {
 369                         $user_ts_type = 'paged';
 370                 } else {
 371                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
 372                                 $func = 'is_' . $type;
 373                                 if ( call_user_func($func) ) {
 374                                         $user_ts_type = $type;
 375                                         break;
 376                                 }
 377                         }
 378                 }
 379                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
 380         } elseif ( is_front_page() ) {
 381                 $redirect['path'] = trailingslashit($redirect['path']);
 382         }
 383
 384         // Strip multiple slashes out of the URL
 385         if ( strpos($redirect['path'], '//') > -1 )
 386                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
 387
 388         // Always trailing slash the Front Page URL
 389         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
 390                 $redirect['path'] = trailingslashit($redirect['path']);
 391
 392         // Ignore differences in host capitalization, as this can lead to infinite redirects
 393         // Only redirect no-www <=> yes-www
 394         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
 395                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
 396                 $redirect['host'] = $original['host'];
 397
 398         $compare_original = array($original['host'], $original['path']);
 399
 400         if ( !empty( $original['port'] ) )
 401                 $compare_original[] = $original['port'];
 402
 403         if ( !empty( $original['query'] ) )
 404                 $compare_original[] = $original['query'];
 405
 406         $compare_redirect = array($redirect['host'], $redirect['path']);
 407
 408         if ( !empty( $redirect['port'] ) )
 409                 $compare_redirect[] = $redirect['port'];
 410
 411         if ( !empty( $redirect['query'] ) )
 412                 $compare_redirect[] = $redirect['query'];
 413
 414         if ( $compare_original !== $compare_redirect ) {
 415                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
 416                 if ( !empty($redirect['port']) )
 417                         $redirect_url .= ':' . $redirect['port'];
 418                 $redirect_url .= $redirect['path'];
 419                 if ( !empty($redirect['query']) )
 420                         $redirect_url .= '?' . $redirect['query'];
 421         }
 422
 423         if ( !$redirect_url || $redirect_url == $requested_url )
 424                 return false;
 425
 426         // Hex encoded octets are case-insensitive.
 427         if ( false !== strpos($requested_url, '%') ) {
 428                 if ( !function_exists('lowercase_octets') ) {
 429                         function lowercase_octets($matches) {
 430                                 return strtolower( $matches[0] );
 431                         }
 432                 }
 433                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
 434         }
 435
 436         /**
 437          * Filter the canonical redirect URL.
 438          *
 439          * Returning false to this filter will cancel the redirect.
 440          *
 441          * @since 2.3.0
 442          *
 443          * @param string $redirect_url  The redirect URL.
 444          * @param string $requested_url The requested URL.
 445          */
 446         $redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
 447
 448         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
 449                 return false;
 450
 451         if ( $do_redirect ) {
 452                 // protect against chained redirects
 453                 if ( !redirect_canonical($redirect_url, false) ) {
 454                         wp_redirect($redirect_url, 301);
 455                         exit();
 456                 } else {
 457                         // Debug
 458                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
 459                         return false;
 460                 }
 461         } else {
 462                 return $redirect_url;
 463         }
 464 }
 465
 466 /**
 467  * Removes arguments from a query string if they are not present in a URL
 468  * DO NOT use this in plugin code.
 469  *
 470  * @since 3.4
 471  * @access private
 472  *
 473  * @return string The altered query string
 474  */
 475 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
 476         $parsed_url = @parse_url( $url );
 477         if ( ! empty( $parsed_url['query'] ) ) {
 478                 parse_str( $parsed_url['query'], $parsed_query );
 479                 foreach ( $args_to_check as $qv ) {
 480                         if ( !isset( $parsed_query[$qv] ) )
 481                                 $query_string = remove_query_arg( $qv, $query_string );
 482                 }
 483         } else {
 484                 $query_string = remove_query_arg( $args_to_check, $query_string );
 485         }
 486         return $query_string;
 487 }
 488
 489 /**
 490  * Attempts to guess the correct URL based on query vars
 491  *
 492  * @since 2.3.0
 493  * @uses $wpdb
 494  *
 495  * @return bool|string The correct URL if one is found. False on failure.
 496  */
 497 function redirect_guess_404_permalink() {
 498         global $wpdb, $wp_rewrite;
 499
 500         if ( get_query_var('name') ) {
 501                 $where = $wpdb->prepare("post_name LIKE %s", like_escape( get_query_var('name') ) . '%');
 502
 503                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
 504                 if ( get_query_var('post_type') )
 505                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
 506                 else
 507                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
 508
 509                 if ( get_query_var('year') )
 510                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
 511                 if ( get_query_var('monthnum') )
 512                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
 513                 if ( get_query_var('day') )
 514                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
 515
 516                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
 517                 if ( ! $post_id )
 518                         return false;
 519                 if ( get_query_var( 'feed' ) )
 520                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
 521                 elseif ( get_query_var( 'page' ) )
 522                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 523                 else
 524                         return get_permalink( $post_id );
 525         }
 526
 527         return false;
 528 }
 529
 530 add_action('template_redirect', 'redirect_canonical');
 531
 532 function wp_redirect_admin_locations() {
 533         global $wp_rewrite;
 534         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
 535                 return;
 536
 537         $admins = array(
 538                 home_url( 'wp-admin', 'relative' ),
 539                 home_url( 'dashboard', 'relative' ),
 540                 home_url( 'admin', 'relative' ),
 541                 site_url( 'dashboard', 'relative' ),
 542                 site_url( 'admin', 'relative' ),
 543         );
 544         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
 545                 wp_redirect( admin_url() );
 546                 exit;
 547         }
 548
 549         $logins = array(
 550                 home_url( 'wp-login.php', 'relative' ),
 551                 home_url( 'login', 'relative' ),
 552                 site_url( 'login', 'relative' ),
 553         );
 554         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
 555                 wp_redirect( site_url( 'wp-login.php', 'login' ) );
 556                 exit;
 557         }
 558 }
 559
 560 add_action( 'template_redirect', 'wp_redirect_admin_locations', 1000 );