wp-includes/canonical.php

   1 <?php
   2 /**
   3  * Canonical API to handle WordPress Redirecting
   4  *
   5  * Based on "Permalink Redirect" from Scott Yang and "Enforce www. Preference"
   6  * by Mark Jaquith
   7  *
   8  * @package WordPress
   9  * @since 2.3.0
  10  */
  11
  12 /**
  13  * Redirects incoming links to the proper URL based on the site url.
  14  *
  15  * Search engines consider www.somedomain.com and somedomain.com to be two
  16  * different URLs when they both go to the same location. This SEO enhancement
  17  * prevents penalty for duplicate content by redirecting all incoming links to
  18  * one or the other.
  19  *
  20  * Prevents redirection for feeds, trackbacks, searches, comment popup, and
  21  * admin URLs. Does not redirect on non-pretty-permalink-supporting IIS 7+,
  22  * page/post previews, WP admin, Trackbacks, robots.txt, searches, or on POST
  23  * requests.
  24  *
  25  * Will also attempt to find the correct link when a user enters a URL that does
  26  * not exist based on exact WordPress query. Will instead try to parse the URL
  27  * or query in an attempt to figure the correct page to go to.
  28  *
  29  * @since 2.3.0
  30  * @uses $wp_rewrite
  31  * @uses $is_IIS
  32  *
  33  * @param string $requested_url Optional. The URL that was requested, used to
  34  *              figure if redirect is needed.
  35  * @param bool $do_redirect Optional. Redirect to the new URL.
  36  * @return null|false|string Null, if redirect not needed. False, if redirect
  37  *              not needed or the string of the URL
  38  */
  39 function redirect_canonical( $requested_url = null, $do_redirect = true ) {
  40         global $wp_rewrite, $is_IIS, $wp_query, $wpdb;
  41
  42         if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ) ) ) {
  43                 return;
  44         }
  45
  46         // If we're not in wp-admin and the post has been published and preview nonce
  47         // is non-existent or invalid then no need for preview in query
  48         if ( is_preview() && get_query_var( 'p' ) && 'publish' == get_post_status( get_query_var( 'p' ) ) ) {
  49                 if ( ! isset( $_GET['preview_id'] )
  50                         || ! isset( $_GET['preview_nonce'] )
  51                         || ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] ) ) {
  52                         $wp_query->is_preview = false;
  53                 }
  54         }
  55
  56         if ( is_trackback() || is_search() || is_comments_popup() || is_admin() || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) ) {
  57                 return;
  58         }
  59
  60         if ( !$requested_url ) {
  61                 // build the URL in the address bar
  62                 $requested_url  = is_ssl() ? 'https://' : 'http://';
  63                 $requested_url .= $_SERVER['HTTP_HOST'];
  64                 $requested_url .= $_SERVER['REQUEST_URI'];
  65         }
  66
  67         $original = @parse_url($requested_url);
  68         if ( false === $original )
  69                 return;
  70
  71         // Some PHP setups turn requests for / into /index.php in REQUEST_URI
  72         // See: https://core.trac.wordpress.org/ticket/5017
  73         // See: https://core.trac.wordpress.org/ticket/7173
  74         // Disabled, for now:
  75         // $original['path'] = preg_replace('|/index\.php$|', '/', $original['path']);
  76
  77         $redirect = $original;
  78         $redirect_url = false;
  79
  80         // Notice fixing
  81         if ( !isset($redirect['path']) )
  82                 $redirect['path'] = '';
  83         if ( !isset($redirect['query']) )
  84                 $redirect['query'] = '';
  85
  86         // If the original URL ended with non-breaking spaces, they were almost
  87         // certainly inserted by accident. Let's remove them, so the reader doesn't
  88         // see a 404 error with no obvious cause.
  89         $redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );
  90
  91         // It's not a preview, so remove it from URL
  92         if ( get_query_var( 'preview' ) ) {
  93                 $redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
  94         }
  95
  96         if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
  97                 if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
  98                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
  99                         $redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
 100                 }
 101         }
 102
 103         if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
 104
 105                 $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
 106
 107                 if ( isset($vars[0]) && $vars = $vars[0] ) {
 108                         if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
 109                                 $id = $vars->post_parent;
 110
 111                         if ( $redirect_url = get_permalink($id) )
 112                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 113                 }
 114         }
 115
 116         // These tests give us a WP-generated permalink
 117         if ( is_404() ) {
 118
 119                 // Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
 120                 $id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
 121                 if ( $id && $redirect_post = get_post($id) ) {
 122                         $post_type_obj = get_post_type_object($redirect_post->post_type);
 123                         if ( $post_type_obj->public ) {
 124                                 $redirect_url = get_permalink($redirect_post);
 125                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 126                         }
 127                 }
 128
 129                 if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
 130                         $year  = get_query_var( 'year' );
 131                         $month = get_query_var( 'monthnum' );
 132                         $day   = get_query_var( 'day' );
 133                         $date  = sprintf( '%04d-%02d-%02d', $year, $month, $day );
 134                         if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
 135                                 $redirect_url = get_month_link( $year, $month );
 136                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
 137                         }
 138                 } elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
 139                         $redirect_url = get_year_link( get_query_var( 'year' ) );
 140                         $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
 141                 }
 142
 143                 if ( ! $redirect_url ) {
 144                         if ( $redirect_url = redirect_guess_404_permalink() ) {
 145                                 $redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
 146                         }
 147                 }
 148
 149         } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
 150                 // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
 151                 if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
 152                         if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
 153                                 $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
 154                 } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
 155                         if ( $redirect_url = get_permalink(get_query_var('p')) )
 156                                 $redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
 157                 } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
 158                         if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
 159                                 $redirect['query'] = remove_query_arg('name', $redirect['query']);
 160                 } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
 161                         if ( $redirect_url = get_permalink(get_query_var('page_id')) )
 162                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 163                 } elseif ( is_page() && !is_feed() && isset($wp_query->queried_object) && 'page' == get_option('show_on_front') && $wp_query->queried_object->ID == get_option('page_on_front')  && ! $redirect_url ) {
 164                         $redirect_url = home_url('/');
 165                 } elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts')  && ! $redirect_url ) {
 166                         if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
 167                                 $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 168                 } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
 169                         $m = get_query_var('m');
 170                         switch ( strlen($m) ) {
 171                                 case 4: // Yearly
 172                                         $redirect_url = get_year_link($m);
 173                                         break;
 174                                 case 6: // Monthly
 175                                         $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
 176                                         break;
 177                                 case 8: // Daily
 178                                         $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
 179                                         break;
 180                         }
 181                         if ( $redirect_url )
 182                                 $redirect['query'] = remove_query_arg('m', $redirect['query']);
 183                 // now moving on to non ?m=X year/month/day links
 184                 } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
 185                         if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
 186                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
 187                 } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
 188                         if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
 189                                 $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
 190                 } elseif ( is_year() && !empty($_GET['year']) ) {
 191                         if ( $redirect_url = get_year_link(get_query_var('year')) )
 192                                 $redirect['query'] = remove_query_arg('year', $redirect['query']);
 193                 } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
 194                         $author = get_userdata(get_query_var('author'));
 195                         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 ) ) ) {
 196                                 if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
 197                                         $redirect['query'] = remove_query_arg('author', $redirect['query']);
 198                         }
 199                 } elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
 200
 201                         $term_count = 0;
 202                         foreach ( $wp_query->tax_query->queried_terms as $tax_query )
 203                                 $term_count += count( $tax_query['terms'] );
 204
 205                         $obj = $wp_query->get_queried_object();
 206                         if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
 207                                 if ( !empty($redirect['query']) ) {
 208                                         // Strip taxonomy query vars off the url.
 209                                         $qv_remove = array( 'term', 'taxonomy');
 210                                         if ( is_category() ) {
 211                                                 $qv_remove[] = 'category_name';
 212                                                 $qv_remove[] = 'cat';
 213                                         } elseif ( is_tag() ) {
 214                                                 $qv_remove[] = 'tag';
 215                                                 $qv_remove[] = 'tag_id';
 216                                         } else { // Custom taxonomies will have a custom query var, remove those too:
 217                                                 $tax_obj = get_taxonomy( $obj->taxonomy );
 218                                                 if ( false !== $tax_obj->query_var )
 219                                                         $qv_remove[] = $tax_obj->query_var;
 220                                         }
 221
 222                                         $rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
 223
 224                                         if ( !array_diff($rewrite_vars, array_keys($_GET))  ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
 225                                                 $redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
 226
 227                                                 // Create the destination url for this taxonomy
 228                                                 $tax_url = parse_url($tax_url);
 229                                                 if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
 230                                                         parse_str($tax_url['query'], $query_vars);
 231                                                         $redirect['query'] = add_query_arg($query_vars, $redirect['query']);
 232                                                 } else { // Taxonomy is accessible via a "pretty-URL"
 233                                                         $redirect['path'] = $tax_url['path'];
 234                                                 }
 235
 236                                         } else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
 237                                                 foreach ( $qv_remove as $_qv ) {
 238                                                         if ( isset($rewrite_vars[$_qv]) )
 239                                                                 $redirect['query'] = remove_query_arg($_qv, $redirect['query']);
 240                                                 }
 241                                         }
 242                                 }
 243
 244                         }
 245                 } elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
 246                         $category = get_category_by_path( $cat );
 247                         $post_terms = wp_get_object_terms($wp_query->get_queried_object_id(), 'category', array('fields' => 'tt_ids'));
 248                         if ( (!$category || is_wp_error($category)) || ( !is_wp_error($post_terms) && !empty($post_terms) && !in_array($category->term_taxonomy_id, $post_terms) ) )
 249                                 $redirect_url = get_permalink($wp_query->get_queried_object_id());
 250                 }
 251
 252                 // Post Paging
 253                 if ( is_singular() && ! is_front_page() && get_query_var('page') ) {
 254                         if ( !$redirect_url )
 255                                 $redirect_url = get_permalink( get_queried_object_id() );
 256                         $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 257                         $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
 258                 }
 259
 260                 // paging and feeds
 261                 if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
 262                         while ( preg_match( "#/$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'] ) ) {
 263                                 // Strip off paging and feed
 264                                 $redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
 265                                 $redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
 266                                 $redirect['path'] = preg_replace("#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing comment paging
 267                         }
 268
 269                         $addl_path = '';
 270                         if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
 271                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 272                                 if ( !is_singular() && get_query_var( 'withcomments' ) )
 273                                         $addl_path .= 'comments/';
 274                                 if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
 275                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
 276                                 else
 277                                         $addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
 278                                 $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
 279                         } elseif ( is_feed() && 'old' == get_query_var('feed') ) {
 280                                 $old_feed_files = array(
 281                                         'wp-atom.php'         => 'atom',
 282                                         'wp-commentsrss2.php' => 'comments_rss2',
 283                                         'wp-feed.php'         => get_default_feed(),
 284                                         'wp-rdf.php'          => 'rdf',
 285                                         'wp-rss.php'          => 'rss2',
 286                                         'wp-rss2.php'         => 'rss2',
 287                                 );
 288                                 if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
 289                                         $redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
 290                                         wp_redirect( $redirect_url, 301 );
 291                                         die();
 292                                 }
 293                         }
 294
 295                         if ( get_query_var('paged') > 0 ) {
 296                                 $paged = get_query_var('paged');
 297                                 $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
 298                                 if ( !is_feed() ) {
 299                                         if ( $paged > 1 && !is_single() ) {
 300                                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
 301                                         } elseif ( !is_single() ) {
 302                                                 $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 303                                         }
 304                                 } elseif ( $paged > 1 ) {
 305                                         $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
 306                                 }
 307                         }
 308
 309                         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 ) ) ) {
 310                                 $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . get_query_var('cpage'), 'commentpaged' );
 311                                 $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 312                         }
 313
 314                         $redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
 315                         if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
 316                                 $redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
 317                         if ( !empty( $addl_path ) )
 318                                 $redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
 319                         $redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
 320                 }
 321
 322                 if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
 323                         if ( is_multisite() ) {
 324                                 /** This filter is documented in wp-login.php */
 325                                 $redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
 326                         } else {
 327                                 $redirect_url = site_url( 'wp-login.php?action=register' );
 328                         }
 329
 330                         wp_redirect( $redirect_url, 301 );
 331                         die();
 332                 }
 333         }
 334
 335         // tack on any additional query vars
 336         $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 337         if ( $redirect_url && !empty($redirect['query']) ) {
 338                 parse_str( $redirect['query'], $_parsed_query );
 339                 $redirect = @parse_url($redirect_url);
 340
 341                 if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
 342                         parse_str( $redirect['query'], $_parsed_redirect_query );
 343
 344                         if ( empty( $_parsed_redirect_query['name'] ) )
 345                                 unset( $_parsed_query['name'] );
 346                 }
 347
 348                 $_parsed_query = rawurlencode_deep( $_parsed_query );
 349                 $redirect_url = add_query_arg( $_parsed_query, $redirect_url );
 350         }
 351
 352         if ( $redirect_url )
 353                 $redirect = @parse_url($redirect_url);
 354
 355         // www.example.com vs example.com
 356         $user_home = @parse_url(home_url());
 357         if ( !empty($user_home['host']) )
 358                 $redirect['host'] = $user_home['host'];
 359         if ( empty($user_home['path']) )
 360                 $user_home['path'] = '/';
 361
 362         // Handle ports
 363         if ( !empty($user_home['port']) )
 364                 $redirect['port'] = $user_home['port'];
 365         else
 366                 unset($redirect['port']);
 367
 368         // trailing /index.php
 369         $redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
 370
 371         // Remove trailing spaces from the path
 372         $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
 373
 374         if ( !empty( $redirect['query'] ) ) {
 375                 // Remove trailing spaces from certain terminating query string args
 376                 $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
 377
 378                 // Clean up empty query strings
 379                 $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
 380
 381                 // Redirect obsolete feeds
 382                 $redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
 383
 384                 // Remove redundant leading ampersands
 385                 $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 386         }
 387
 388         // strip /index.php/ when we're not using PATHINFO permalinks
 389         if ( !$wp_rewrite->using_index_permalinks() )
 390                 $redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
 391
 392         // trailing slashes
 393         if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
 394                 $user_ts_type = '';
 395                 if ( get_query_var('paged') > 0 ) {
 396                         $user_ts_type = 'paged';
 397                 } else {
 398                         foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
 399                                 $func = 'is_' . $type;
 400                                 if ( call_user_func($func) ) {
 401                                         $user_ts_type = $type;
 402                                         break;
 403                                 }
 404                         }
 405                 }
 406                 $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
 407         } elseif ( is_front_page() ) {
 408                 $redirect['path'] = trailingslashit($redirect['path']);
 409         }
 410
 411         // Strip multiple slashes out of the URL
 412         if ( strpos($redirect['path'], '//') > -1 )
 413                 $redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
 414
 415         // Always trailing slash the Front Page URL
 416         if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
 417                 $redirect['path'] = trailingslashit($redirect['path']);
 418
 419         // Ignore differences in host capitalization, as this can lead to infinite redirects
 420         // Only redirect no-www <=> yes-www
 421         if ( strtolower($original['host']) == strtolower($redirect['host']) ||
 422                 ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
 423                 $redirect['host'] = $original['host'];
 424
 425         $compare_original = array( $original['host'], $original['path'] );
 426
 427         if ( !empty( $original['port'] ) )
 428                 $compare_original[] = $original['port'];
 429
 430         if ( !empty( $original['query'] ) )
 431                 $compare_original[] = $original['query'];
 432
 433         $compare_redirect = array( $redirect['host'], $redirect['path'] );
 434
 435         if ( !empty( $redirect['port'] ) )
 436                 $compare_redirect[] = $redirect['port'];
 437
 438         if ( !empty( $redirect['query'] ) )
 439                 $compare_redirect[] = $redirect['query'];
 440
 441         if ( $compare_original !== $compare_redirect ) {
 442                 $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
 443                 if ( !empty($redirect['port']) )
 444                         $redirect_url .= ':' . $redirect['port'];
 445                 $redirect_url .= $redirect['path'];
 446                 if ( !empty($redirect['query']) )
 447                         $redirect_url .= '?' . $redirect['query'];
 448         }
 449
 450         if ( !$redirect_url || $redirect_url == $requested_url )
 451                 return false;
 452
 453         // Hex encoded octets are case-insensitive.
 454         if ( false !== strpos($requested_url, '%') ) {
 455                 if ( !function_exists('lowercase_octets') ) {
 456                         function lowercase_octets($matches) {
 457                                 return strtolower( $matches[0] );
 458                         }
 459                 }
 460                 $requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
 461         }
 462
 463         /**
 464          * Filter the canonical redirect URL.
 465          *
 466          * Returning false to this filter will cancel the redirect.
 467          *
 468          * @since 2.3.0
 469          *
 470          * @param string $redirect_url  The redirect URL.
 471          * @param string $requested_url The requested URL.
 472          */
 473         $redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
 474
 475         if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
 476                 return false;
 477
 478         if ( $do_redirect ) {
 479                 // protect against chained redirects
 480                 if ( !redirect_canonical($redirect_url, false) ) {
 481                         wp_redirect($redirect_url, 301);
 482                         exit();
 483                 } else {
 484                         // Debug
 485                         // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
 486                         return false;
 487                 }
 488         } else {
 489                 return $redirect_url;
 490         }
 491 }
 492
 493 /**
 494  * Removes arguments from a query string if they are not present in a URL
 495  * DO NOT use this in plugin code.
 496  *
 497  * @since 3.4.0
 498  * @access private
 499  *
 500  * @param string $query_string
 501  * @param array $args_to_check
 502  * @param string $url
 503  * @return string The altered query string
 504  */
 505 function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
 506         $parsed_url = @parse_url( $url );
 507         if ( ! empty( $parsed_url['query'] ) ) {
 508                 parse_str( $parsed_url['query'], $parsed_query );
 509                 foreach ( $args_to_check as $qv ) {
 510                         if ( !isset( $parsed_query[$qv] ) )
 511                                 $query_string = remove_query_arg( $qv, $query_string );
 512                 }
 513         } else {
 514                 $query_string = remove_query_arg( $args_to_check, $query_string );
 515         }
 516         return $query_string;
 517 }
 518
 519 /**
 520  * Attempts to guess the correct URL based on query vars
 521  *
 522  * @since 2.3.0
 523  *
 524  * @global wpdb $wpdb WordPress database abstraction object.
 525  *
 526  * @return bool|string The correct URL if one is found. False on failure.
 527  */
 528 function redirect_guess_404_permalink() {
 529         global $wpdb, $wp_rewrite;
 530
 531         if ( get_query_var('name') ) {
 532                 $where = $wpdb->prepare("post_name LIKE %s", $wpdb->esc_like( get_query_var('name') ) . '%');
 533
 534                 // if any of post_type, year, monthnum, or day are set, use them to refine the query
 535                 if ( get_query_var('post_type') )
 536                         $where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
 537                 else
 538                         $where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
 539
 540                 if ( get_query_var('year') )
 541                         $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
 542                 if ( get_query_var('monthnum') )
 543                         $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
 544                 if ( get_query_var('day') )
 545                         $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
 546
 547                 $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
 548                 if ( ! $post_id )
 549                         return false;
 550                 if ( get_query_var( 'feed' ) )
 551                         return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
 552                 elseif ( get_query_var( 'page' ) )
 553                         return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
 554                 else
 555                         return get_permalink( $post_id );
 556         }
 557
 558         return false;
 559 }
 560
 561 function wp_redirect_admin_locations() {
 562         global $wp_rewrite;
 563         if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
 564                 return;
 565
 566         $admins = array(
 567                 home_url( 'wp-admin', 'relative' ),
 568                 home_url( 'dashboard', 'relative' ),
 569                 home_url( 'admin', 'relative' ),
 570                 site_url( 'dashboard', 'relative' ),
 571                 site_url( 'admin', 'relative' ),
 572         );
 573         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
 574                 wp_redirect( admin_url() );
 575                 exit;
 576         }
 577
 578         $logins = array(
 579                 home_url( 'wp-login.php', 'relative' ),
 580                 home_url( 'login', 'relative' ),
 581                 site_url( 'login', 'relative' ),
 582         );
 583         if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
 584                 wp_redirect( site_url( 'wp-login.php', 'login' ) );
 585                 exit;
 586         }
 587 }