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/wp-includes/ -> canonical.php (source)

   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   * @author Scott Yang
   9   * @author Mark Jaquith
  10   * @package WordPress
  11   * @since 2.3.0
  12   */
  13  
  14  /**
  15   * Redirects incoming links to the proper URL based on the site url.
  16   *
  17   * Search engines consider www.somedomain.com and somedomain.com to be two
  18   * different URLs when they both go to the same location. This SEO enhancement
  19   * prevents penality for duplicate content by redirecting all incoming links to
  20   * one or the other.
  21   *
  22   * Prevents redirection for feeds, trackbacks, searches, comment popup, and
  23   * admin URLs. Does not redirect on IIS, page/post previews, and on form data.
  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() || $is_IIS || ( isset($_POST) && count($_POST) ) || is_preview() || is_robots() )
  43          return;
  44  
  45      if ( !$requested_url ) {
  46          // build the URL in the address bar
  47          $requested_url  = ( !empty($_SERVER['HTTPS'] ) && strtolower($_SERVER['HTTPS']) == 'on' ) ? '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']) )  $redirect['path'] = '';
  67      if ( !isset($redirect['query']) ) $redirect['query'] = '';
  68  
  69      if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
  70  
  71          $vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
  72  
  73          if ( isset($vars[0]) && $vars = $vars[0] ) {
  74              if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
  75                  $id = $vars->post_parent;
  76  
  77              if ( $redirect_url = get_permalink($id) )
  78                  $redirect['query'] = remove_query_arg(array('p', 'page_id', 'attachment_id'), $redirect['query']);
  79          }
  80      }
  81  
  82      // These tests give us a WP-generated permalink
  83      if ( is_404() ) {
  84          $redirect_url = redirect_guess_404_permalink();
  85      } elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
  86          // rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
  87          if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {
  88              if ( $redirect_url = get_attachment_link(get_query_var('attachment_id')) )
  89                  $redirect['query'] = remove_query_arg('attachment_id', $redirect['query']);
  90          } elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
  91              if ( $redirect_url = get_permalink(get_query_var('p')) )
  92                  $redirect['query'] = remove_query_arg('p', $redirect['query']);
  93              if ( get_query_var( 'page' ) ) {
  94                  $redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
  95                  $redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
  96              }
  97          } elseif ( is_single() && !empty($_GET['name'])  && ! $redirect_url ) {
  98              if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
  99                  $redirect['query'] = remove_query_arg('name', $redirect['query']);
 100          } elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
 101              if ( $redirect_url = get_permalink(get_query_var('page_id')) )
 102                  $redirect['query'] = remove_query_arg('page_id', $redirect['query']);
 103          } elseif ( !empty($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {
 104              $m = get_query_var('m');
 105              switch ( strlen($m) ) {
 106                  case 4: // Yearly
 107                      $redirect_url = get_year_link($m);
 108                      break;
 109                  case 6: // Monthly
 110                      $redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );
 111                      break;
 112                  case 8: // Daily
 113                      $redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));
 114                      break;
 115              }
 116              if ( $redirect_url )
 117                  $redirect['query'] = remove_query_arg('m', $redirect['query']);
 118          // now moving on to non ?m=X year/month/day links
 119          } elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_GET['day']) ) {
 120              if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )
 121                  $redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);
 122          } elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
 123              if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
 124                  $redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
 125          } elseif ( is_year() && !empty($_GET['year']) ) {
 126              if ( $redirect_url = get_year_link(get_query_var('year')) )
 127                  $redirect['query'] = remove_query_arg('year', $redirect['query']);
 128          } elseif ( is_category() && !empty($_GET['cat']) && preg_match( '|^[0-9]+$|', $_GET['cat'] ) ) {
 129              if ( $redirect_url = get_category_link(get_query_var('cat')) )
 130                  $redirect['query'] = remove_query_arg('cat', $redirect['query']);
 131          } elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
 132              $author = get_userdata(get_query_var('author'));
 133              if ( false !== $author && $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
 134                  $redirect['query'] = remove_query_arg('author', $redirect['author']);
 135          }
 136  
 137      // paging and feeds
 138          if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
 139              if ( !$redirect_url )
 140                  $redirect_url = $requested_url;
 141              $paged_redirect = @parse_url($redirect_url);
 142              while ( preg_match( '#/page/[0-9]+?(/+)?$#', $paged_redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $paged_redirect['path'] ) || preg_match( '#/comment-page-[0-9]+(/+)?$#', $paged_redirect['path'] ) ) {
 143                  // Strip off paging and feed
 144                  $paged_redirect['path'] = preg_replace('#/page/[0-9]+?(/+)?$#', '/', $paged_redirect['path']); // strip off any existing paging
 145                  $paged_redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $paged_redirect['path']); // strip off feed endings
 146                  $paged_redirect['path'] = preg_replace('#/comment-page-[0-9]+?(/+)?$#', '/', $paged_redirect['path']); // strip off any existing comment paging
 147              }
 148  
 149              $addl_path = '';
 150              if ( is_feed() ) {
 151                  $addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
 152                  if ( get_query_var( 'withcomments' ) )
 153                      $addl_path .= 'comments/';
 154                  $addl_path .= user_trailingslashit( 'feed/' . ( ( 'rss2' ==  get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
 155                  $redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
 156              }
 157  
 158              if ( get_query_var('paged') > 0 ) {
 159                  $paged = get_query_var('paged');
 160                  $redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
 161                  if ( !is_feed() ) {
 162                      if ( $paged > 1 && !is_single() ) {
 163                          $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("page/$paged", 'paged');
 164                      } elseif ( !is_single() ) {
 165                          $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit($paged_redirect['path'], 'paged');
 166                      }
 167                  } elseif ( $paged > 1 ) {
 168                      $redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
 169                  }
 170              }
 171  
 172              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 ) ) ) {
 173                  $addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( 'comment-page-' . get_query_var('cpage'), 'commentpaged' );
 174                  $redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
 175              }
 176  
 177              $paged_redirect['path'] = user_trailingslashit( preg_replace('|/index.php/?$|', '/', $paged_redirect['path']) ); // strip off trailing /index.php/
 178              if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($paged_redirect['path'], '/index.php/') === false )
 179                  $paged_redirect['path'] = trailingslashit($paged_redirect['path']) . 'index.php/';
 180              if ( !empty( $addl_path ) )
 181                  $paged_redirect['path'] = trailingslashit($paged_redirect['path']) . $addl_path;
 182              $redirect_url = $paged_redirect['scheme'] . '://' . $paged_redirect['host'] . $paged_redirect['path'];
 183              $redirect['path'] = $paged_redirect['path'];
 184          }
 185      }
 186  
 187      // tack on any additional query vars
 188      $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 189      if ( $redirect_url && !empty($redirect['query']) ) {
 190          if ( strpos($redirect_url, '?') !== false )
 191              $redirect_url .= '&';
 192          else
 193              $redirect_url .= '?';
 194          $redirect_url .= $redirect['query'];
 195      }
 196  
 197      if ( $redirect_url )
 198          $redirect = @parse_url($redirect_url);
 199  
 200      // www.example.com vs example.com
 201      $user_home = @parse_url(get_option('home'));
 202      if ( !empty($user_home['host']) )
 203          $redirect['host'] = $user_home['host'];
 204      if ( empty($user_home['path']) )
 205          $user_home['path'] = '/';
 206  
 207      // Handle ports
 208      if ( !empty($user_home['port']) )
 209          $redirect['port'] = $user_home['port'];
 210      else
 211          unset($redirect['port']);
 212  
 213      // trailing /index.php
 214      $redirect['path'] = preg_replace('|/index.php/*?$|', '/', $redirect['path']);
 215  
 216      // Remove trailing spaces from the path
 217      $redirect['path'] = preg_replace( '#(%20| )+$#', '', $redirect['path'] );
 218  
 219      if ( !empty( $redirect['query'] ) ) {
 220          // Remove trailing spaces from certain terminating query string args
 221          $redirect['query'] = preg_replace( '#((p|page_id|cat|tag)=[^&]*?)(%20| )+$#', '$1', $redirect['query'] );
 222  
 223          // Clean up empty query strings
 224          $redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
 225  
 226          // Remove redundant leading ampersands
 227          $redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
 228      }
 229  
 230      // strip /index.php/ when we're not using PATHINFO permalinks
 231      if ( !$wp_rewrite->using_index_permalinks() )
 232          $redirect['path'] = str_replace('/index.php/', '/', $redirect['path']);
 233  
 234      // trailing slashes
 235      if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (get_query_var('paged') > 1) ) ) ) {
 236          $user_ts_type = '';
 237          if ( get_query_var('paged') > 0 ) {
 238              $user_ts_type = 'paged';
 239          } else {
 240              foreach ( array('single', 'category', 'page', 'day', 'month', 'year', 'home') as $type ) {
 241                  $func = 'is_' . $type;
 242                  if ( call_user_func($func) ) {
 243                      $user_ts_type = $type;
 244                      break;
 245                  }
 246              }
 247          }
 248          $redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);
 249      } elseif ( is_front_page() ) {
 250          $redirect['path'] = trailingslashit($redirect['path']);
 251      }
 252  
 253      // Always trailing slash the Front Page URL
 254      if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
 255          $redirect['path'] = trailingslashit($redirect['path']);
 256  
 257      // Ignore differences in host capitalization, as this can lead to infinite redirects
 258      // Only redirect no-www <=> yes-www
 259      if ( strtolower($original['host']) == strtolower($redirect['host']) ||
 260          ( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
 261          $redirect['host'] = $original['host'];
 262  
 263      $compare_original = array($original['host'], $original['path']);
 264  
 265      if ( !empty( $original['port'] ) )
 266          $compare_original[] = $original['port'];
 267  
 268      if ( !empty( $original['query'] ) )
 269          $compare_original[] = $original['query'];
 270  
 271      $compare_redirect = array($redirect['host'], $redirect['path']);
 272  
 273      if ( !empty( $redirect['port'] ) )
 274          $compare_redirect[] = $redirect['port'];
 275  
 276      if ( !empty( $redirect['query'] ) )
 277          $compare_redirect[] = $redirect['query'];
 278  
 279      if ( $compare_original !== $compare_redirect ) {
 280          $redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
 281          if ( !empty($redirect['port']) )
 282              $redirect_url .= ':' . $redirect['port'];
 283          $redirect_url .= $redirect['path'];
 284          if ( !empty($redirect['query']) )
 285              $redirect_url .= '?' . $redirect['query'];
 286      }
 287  
 288      if ( $redirect_url == $requested_url )
 289          return false;
 290  
 291      // Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning FALSE
 292      $redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);
 293  
 294      if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request
 295          return false;
 296  
 297      if ( $do_redirect ) {
 298          // protect against chained redirects
 299          if ( !redirect_canonical($redirect_url, false) ) {
 300              wp_redirect($redirect_url, 301);
 301              exit();
 302          } else {
 303              // Debug
 304              // die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
 305              return false;
 306          }
 307      } else {
 308          return $redirect_url;
 309      }
 310  }
 311  
 312  /**
 313   * Attempts to guess correct post based on query vars.
 314   *
 315   * @since 2.3.0
 316   * @uses $wpdb
 317   *
 318   * @return bool|string Returns False, if it can't find post, returns correct
 319   *        location on success.
 320   */
 321  function redirect_guess_404_permalink() {
 322      global $wpdb;
 323  
 324      if ( !get_query_var('name') )
 325          return false;
 326  
 327      $where = $wpdb->prepare("post_name LIKE %s", get_query_var('name') . '%');
 328  
 329      // if any of year, monthnum, or day are set, use them to refine the query
 330      if ( get_query_var('year') )
 331          $where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
 332      if ( get_query_var('monthnum') )
 333          $where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
 334      if ( get_query_var('day') )
 335          $where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
 336  
 337      $post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
 338      if ( !$post_id )
 339          return false;
 340      return get_permalink($post_id);
 341  }
 342  
 343  add_action('template_redirect', 'redirect_canonical');
 344  
 345  ?>


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