redirect_canonical

函数
redirect_canonical ( $requested_url = null, $do_redirect = true )
参数
  • (string) $requested_url Optional. The URL that was requested, used to figure if redirect is needed.
    Required:
    Default: null
  • (bool) $do_redirect Optional. Redirect to the new URL.
    Required:
    Default: true
返回值
  • (string|void) The string of the URL, if redirect needed.
定义位置
相关方法
rel_canonicalredirect_postwp_get_canonical_urlwp_admin_canonical_urlwp_redirect_admin_locations
引入
2.3.0
弃用
-

redirect_canonical:这是一个WordPress函数,用于将URL重定向到它们的规范版本: 这个函数有助于防止重复内容问题,确保对一个给定的页面或文章的所有请求都被重定向到相同的规范URL。

根据网站的网址,将传入的链接重定向到适当的URL。

搜索引擎认为www.somedomain.com 和somedomain.com是两个不同的URL,当它们都指向同一个位置时。这一SEO改进措施通过将所有进入的链接重定向到一个或另一个来防止重复内容的惩罚。

防止对feeds、trackbacks、search和admin URLs的重定向。在不支持permalink的IIS 7+、页面/文章预览、WP管理、Trackbacks、robots.txt、favicon.ico、搜索或POST请求上不会重定向。

当用户输入一个基于WordPress确切查询的不存在的URL时,也会尝试找到正确的链接。相反,它将尝试解析URL或查询,以试图找出正确的页面。

function redirect_canonical( $requested_url = null, $do_redirect = true ) {
	global $wp_rewrite, $is_IIS, $wp_query, $wpdb, $wp;

	if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ), true ) ) {
		return;
	}

	// If we're not in wp-admin and the post has been published and preview nonce
	// is non-existent or invalid then no need for preview in query.
	if ( is_preview() && get_query_var( 'p' ) && 'publish' === get_post_status( get_query_var( 'p' ) ) ) {
		if ( ! isset( $_GET['preview_id'] )
			|| ! isset( $_GET['preview_nonce'] )
			|| ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] )
		) {
			$wp_query->is_preview = false;
		}
	}

	if ( is_admin() || is_search() || is_preview() || is_trackback() || is_favicon()
		|| ( $is_IIS && ! iis7_supports_permalinks() )
	) {
		return;
	}

	if ( ! $requested_url && isset( $_SERVER['HTTP_HOST'] ) ) {
		// Build the URL in the address bar.
		$requested_url  = is_ssl() ? 'https://' : 'http://';
		$requested_url .= $_SERVER['HTTP_HOST'];
		$requested_url .= $_SERVER['REQUEST_URI'];
	}

	$original = parse_url( $requested_url );
	if ( false === $original ) {
		return;
	}

	$redirect     = $original;
	$redirect_url = false;
	$redirect_obj = false;

	// Notice fixing.
	if ( ! isset( $redirect['path'] ) ) {
		$redirect['path'] = '';
	}
	if ( ! isset( $redirect['query'] ) ) {
		$redirect['query'] = '';
	}

	/*
	 * If the original URL ended with non-breaking spaces, they were almost
	 * certainly inserted by accident. Let's remove them, so the reader doesn't
	 * see a 404 error with no obvious cause.
	 */
	$redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );

	// It's not a preview, so remove it from URL.
	if ( get_query_var( 'preview' ) ) {
		$redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
	}

	$post_id = get_query_var( 'p' );

	if ( is_feed() && $post_id ) {
		$redirect_url = get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
		$redirect_obj = get_post( $post_id );

		if ( $redirect_url ) {
			$redirect['query'] = _remove_qs_args_if_not_in_url(
				$redirect['query'],
				array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed' ),
				$redirect_url
			);

			$redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
		}
	}

	if ( is_singular() && $wp_query->post_count < 1 && $post_id ) {

		$vars = $wpdb->get_results( $wpdb->prepare( "SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $post_id ) );

		if ( ! empty( $vars[0] ) ) {
			$vars = $vars[0];

			if ( 'revision' === $vars->post_type && $vars->post_parent > 0 ) {
				$post_id = $vars->post_parent;
			}

			$redirect_url = get_permalink( $post_id );
			$redirect_obj = get_post( $post_id );

			if ( $redirect_url ) {
				$redirect['query'] = _remove_qs_args_if_not_in_url(
					$redirect['query'],
					array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ),
					$redirect_url
				);
			}
		}
	}

	// These tests give us a WP-generated permalink.
	if ( is_404() ) {

		// Redirect ?page_id, ?p=, ?attachment_id= to their respective URLs.
		$post_id = max( get_query_var( 'p' ), get_query_var( 'page_id' ), get_query_var( 'attachment_id' ) );

		$redirect_post = $post_id ? get_post( $post_id ) : false;

		if ( $redirect_post ) {
			$post_type_obj = get_post_type_object( $redirect_post->post_type );

			if ( $post_type_obj && $post_type_obj->public && 'auto-draft' !== $redirect_post->post_status ) {
				$redirect_url = get_permalink( $redirect_post );
				$redirect_obj = get_post( $redirect_post );

				$redirect['query'] = _remove_qs_args_if_not_in_url(
					$redirect['query'],
					array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ),
					$redirect_url
				);
			}
		}

		$year  = get_query_var( 'year' );
		$month = get_query_var( 'monthnum' );
		$day   = get_query_var( 'day' );

		if ( $year && $month && $day ) {
			$date = sprintf( '%04d-%02d-%02d', $year, $month, $day );

			if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
				$redirect_url = get_month_link( $year, $month );

				$redirect['query'] = _remove_qs_args_if_not_in_url(
					$redirect['query'],
					array( 'year', 'monthnum', 'day' ),
					$redirect_url
				);
			}
		} elseif ( $year && $month && $month > 12 ) {
			$redirect_url = get_year_link( $year );

			$redirect['query'] = _remove_qs_args_if_not_in_url(
				$redirect['query'],
				array( 'year', 'monthnum' ),
				$redirect_url
			);
		}

		// Strip off non-existing <!--nextpage--> links from single posts or pages.
		if ( get_query_var( 'page' ) ) {
			$post_id = 0;

			if ( $wp_query->queried_object instanceof WP_Post ) {
				$post_id = $wp_query->queried_object->ID;
			} elseif ( $wp_query->post ) {
				$post_id = $wp_query->post->ID;
			}

			if ( $post_id ) {
				$redirect_url = get_permalink( $post_id );
				$redirect_obj = get_post( $post_id );

				$redirect['path']  = rtrim( $redirect['path'], (int) get_query_var( 'page' ) . '/' );
				$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
			}
		}

		if ( ! $redirect_url ) {
			$redirect_url = redirect_guess_404_permalink();

			if ( $redirect_url ) {
				$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
				);
			}
		}
	} elseif ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) {

		// Rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101.
		if ( is_attachment()
			&& ! array_diff( array_keys( $wp->query_vars ), array( 'attachment', 'attachment_id' ) )
			&& ! $redirect_url
		) {
			if ( ! empty( $_GET['attachment_id'] ) ) {
				$redirect_url = get_attachment_link( get_query_var( 'attachment_id' ) );
				$redirect_obj = get_post( get_query_var( 'attachment_id' ) );

				if ( $redirect_url ) {
					$redirect['query'] = remove_query_arg( 'attachment_id', $redirect['query'] );
				}
			} else {
				$redirect_url = get_attachment_link();
				$redirect_obj = get_post();
			}
		} elseif ( is_single() && ! empty( $_GET['p'] ) && ! $redirect_url ) {
			$redirect_url = get_permalink( get_query_var( 'p' ) );
			$redirect_obj = get_post( get_query_var( 'p' ) );

			if ( $redirect_url ) {
				$redirect['query'] = remove_query_arg( array( 'p', 'post_type' ), $redirect['query'] );
			}
		} elseif ( is_single() && ! empty( $_GET['name'] ) && ! $redirect_url ) {
			$redirect_url = get_permalink( $wp_query->get_queried_object_id() );
			$redirect_obj = get_post( $wp_query->get_queried_object_id() );

			if ( $redirect_url ) {
				$redirect['query'] = remove_query_arg( 'name', $redirect['query'] );
			}
		} elseif ( is_page() && ! empty( $_GET['page_id'] ) && ! $redirect_url ) {
			$redirect_url = get_permalink( get_query_var( 'page_id' ) );
			$redirect_obj = get_post( get_query_var( 'page_id' ) );

			if ( $redirect_url ) {
				$redirect['query'] = remove_query_arg( 'page_id', $redirect['query'] );
			}
		} elseif ( is_page() && ! is_feed() && ! $redirect_url
			&& 'page' === get_option( 'show_on_front' ) && get_queried_object_id() === (int) get_option( 'page_on_front' )
		) {
			$redirect_url = home_url( '/' );
		} elseif ( is_home() && ! empty( $_GET['page_id'] ) && ! $redirect_url
			&& 'page' === get_option( 'show_on_front' ) && get_query_var( 'page_id' ) === (int) get_option( 'page_for_posts' )
		) {
			$redirect_url = get_permalink( get_option( 'page_for_posts' ) );
			$redirect_obj = get_post( get_option( 'page_for_posts' ) );

			if ( $redirect_url ) {
				$redirect['query'] = remove_query_arg( 'page_id', $redirect['query'] );
			}
		} elseif ( ! empty( $_GET['m'] ) && ( is_year() || is_month() || is_day() ) ) {
			$m = get_query_var( 'm' );

			switch ( strlen( $m ) ) {
				case 4: // Yearly.
					$redirect_url = get_year_link( $m );
					break;
				case 6: // Monthly.
					$redirect_url = get_month_link( substr( $m, 0, 4 ), substr( $m, 4, 2 ) );
					break;
				case 8: // Daily.
					$redirect_url = get_day_link( substr( $m, 0, 4 ), substr( $m, 4, 2 ), substr( $m, 6, 2 ) );
					break;
			}

			if ( $redirect_url ) {
				$redirect['query'] = remove_query_arg( 'm', $redirect['query'] );
			}
			// Now moving on to non ?m=X year/month/day links.
		} elseif ( is_date() ) {
			$year  = get_query_var( 'year' );
			$month = get_query_var( 'monthnum' );
			$day   = get_query_var( 'day' );

			if ( is_day() && $year && $month && ! empty( $_GET['day'] ) ) {
				$redirect_url = get_day_link( $year, $month, $day );

				if ( $redirect_url ) {
					$redirect['query'] = remove_query_arg( array( 'year', 'monthnum', 'day' ), $redirect['query'] );
				}
			} elseif ( is_month() && $year && ! empty( $_GET['monthnum'] ) ) {
				$redirect_url = get_month_link( $year, $month );

				if ( $redirect_url ) {
					$redirect['query'] = remove_query_arg( array( 'year', 'monthnum' ), $redirect['query'] );
				}
			} elseif ( is_year() && ! empty( $_GET['year'] ) ) {
				$redirect_url = get_year_link( $year );

				if ( $redirect_url ) {
					$redirect['query'] = remove_query_arg( 'year', $redirect['query'] );
				}
			}
		} elseif ( is_author() && ! empty( $_GET['author'] ) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
			$author = get_userdata( get_query_var( 'author' ) );

			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 ) )
			) {
				$redirect_url = get_author_posts_url( $author->ID, $author->user_nicename );
				$redirect_obj = $author;

				if ( $redirect_url ) {
					$redirect['query'] = remove_query_arg( 'author', $redirect['query'] );
				}
			}
		} elseif ( is_category() || is_tag() || is_tax() ) { // Terms (tags/categories).
			$term_count = 0;

			foreach ( $wp_query->tax_query->queried_terms as $tax_query ) {
				$term_count += count( $tax_query['terms'] );
			}

			$obj = $wp_query->get_queried_object();

			if ( $term_count <= 1 && ! empty( $obj->term_id ) ) {
				$tax_url = get_term_link( (int) $obj->term_id, $obj->taxonomy );

				if ( $tax_url && ! is_wp_error( $tax_url ) ) {
					if ( ! empty( $redirect['query'] ) ) {
						// Strip taxonomy query vars off the URL.
						$qv_remove = array( 'term', 'taxonomy' );

						if ( is_category() ) {
							$qv_remove[] = 'category_name';
							$qv_remove[] = 'cat';
						} elseif ( is_tag() ) {
							$qv_remove[] = 'tag';
							$qv_remove[] = 'tag_id';
						} else {
							// Custom taxonomies will have a custom query var, remove those too.
							$tax_obj = get_taxonomy( $obj->taxonomy );
							if ( false !== $tax_obj->query_var ) {
								$qv_remove[] = $tax_obj->query_var;
							}
						}

						$rewrite_vars = array_diff( array_keys( $wp_query->query ), array_keys( $_GET ) );

						// Check to see if all the query vars are coming from the rewrite, none are set via $_GET.
						if ( ! array_diff( $rewrite_vars, array_keys( $_GET ) ) ) {
							// Remove all of the per-tax query vars.
							$redirect['query'] = remove_query_arg( $qv_remove, $redirect['query'] );

							// Create the destination URL for this taxonomy.
							$tax_url = parse_url( $tax_url );

							if ( ! empty( $tax_url['query'] ) ) {
								// Taxonomy accessible via ?taxonomy=...&term=... or any custom query var.
								parse_str( $tax_url['query'], $query_vars );
								$redirect['query'] = add_query_arg( $query_vars, $redirect['query'] );
							} else {
								// Taxonomy is accessible via a "pretty URL".
								$redirect['path'] = $tax_url['path'];
							}
						} else {
							// Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite.
							foreach ( $qv_remove as $_qv ) {
								if ( isset( $rewrite_vars[ $_qv ] ) ) {
									$redirect['query'] = remove_query_arg( $_qv, $redirect['query'] );
								}
							}
						}
					}
				}
			}
		} elseif ( is_single() && strpos( $wp_rewrite->permalink_structure, '%category%' ) !== false ) {
			$category_name = get_query_var( 'category_name' );

			if ( $category_name ) {
				$category = get_category_by_path( $category_name );

				if ( ! $category || is_wp_error( $category )
					|| ! has_term( $category->term_id, 'category', $wp_query->get_queried_object_id() )
				) {
					$redirect_url = get_permalink( $wp_query->get_queried_object_id() );
					$redirect_obj = get_post( $wp_query->get_queried_object_id() );
				}
			}
		}

		// Post paging.
		if ( is_singular() && get_query_var( 'page' ) ) {
			$page = get_query_var( 'page' );

			if ( ! $redirect_url ) {
				$redirect_url = get_permalink( get_queried_object_id() );
				$redirect_obj = get_post( get_queried_object_id() );
			}

			if ( $page > 1 ) {
				$redirect_url = trailingslashit( $redirect_url );

				if ( is_front_page() ) {
					$redirect_url .= user_trailingslashit( "$wp_rewrite->pagination_base/$page", 'paged' );
				} else {
					$redirect_url .= user_trailingslashit( $page, 'single_paged' );
				}
			}

			$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
		}

		if ( get_query_var( 'sitemap' ) ) {
			$redirect_url      = get_sitemap_url( get_query_var( 'sitemap' ), get_query_var( 'sitemap-subtype' ), get_query_var( 'paged' ) );
			$redirect['query'] = remove_query_arg( array( 'sitemap', 'sitemap-subtype', 'paged' ), $redirect['query'] );
		} elseif ( get_query_var( 'paged' ) || is_feed() || get_query_var( 'cpage' ) ) {
			// Paging and feeds.
			$paged = get_query_var( 'paged' );
			$feed  = get_query_var( 'feed' );
			$cpage = get_query_var( 'cpage' );

			while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] )
				|| preg_match( '#/(comments/?)?(feed|rss2?|rdf|atom)(/+)?$#', $redirect['path'] )
				|| preg_match( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+(/+)?$#", $redirect['path'] )
			) {
				// Strip off any existing paging.
				$redirect['path'] = preg_replace( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path'] );
				// Strip off feed endings.
				$redirect['path'] = preg_replace( '#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path'] );
				// Strip off any existing comment paging.
				$redirect['path'] = preg_replace( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path'] );
			}

			$addl_path    = '';
			$default_feed = get_default_feed();

			if ( is_feed() && in_array( $feed, $wp_rewrite->feeds, true ) ) {
				$addl_path = ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '';

				if ( ! is_singular() && get_query_var( 'withcomments' ) ) {
					$addl_path .= 'comments/';
				}

				if ( ( 'rss' === $default_feed && 'feed' === $feed ) || 'rss' === $feed ) {
					$format = ( 'rss2' === $default_feed ) ? '' : 'rss2';
				} else {
					$format = ( $default_feed === $feed || 'feed' === $feed ) ? '' : $feed;
				}

				$addl_path .= user_trailingslashit( 'feed/' . $format, 'feed' );

				$redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
			} elseif ( is_feed() && 'old' === $feed ) {
				$old_feed_files = array(
					'wp-atom.php'         => 'atom',
					'wp-commentsrss2.php' => 'comments_rss2',
					'wp-feed.php'         => $default_feed,
					'wp-rdf.php'          => 'rdf',
					'wp-rss.php'          => 'rss2',
					'wp-rss2.php'         => 'rss2',
				);

				if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
					$redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );

					wp_redirect( $redirect_url, 301 );
					die();
				}
			}

			if ( $paged > 0 ) {
				$redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );

				if ( ! is_feed() ) {
					if ( ! is_single() ) {
						$addl_path = ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '';

						if ( $paged > 1 ) {
							$addl_path .= user_trailingslashit( "$wp_rewrite->pagination_base/$paged", 'paged' );
						}
					}
				} elseif ( $paged > 1 ) {
					$redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
				}
			}

			$default_comments_page = get_option( 'default_comments_page' );

			if ( get_option( 'page_comments' )
				&& ( 'newest' === $default_comments_page && $cpage > 0
					|| 'newest' !== $default_comments_page && $cpage > 1 )
			) {
				$addl_path  = ( ! empty( $addl_path ) ? trailingslashit( $addl_path ) : '' );
				$addl_path .= user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . $cpage, 'commentpaged' );

				$redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
			}

			// Strip off trailing /index.php/.
			$redirect['path'] = preg_replace( '|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path'] );
			$redirect['path'] = user_trailingslashit( $redirect['path'] );

			if ( ! empty( $addl_path )
				&& $wp_rewrite->using_index_permalinks()
				&& strpos( $redirect['path'], '/' . $wp_rewrite->index . '/' ) === false
			) {
				$redirect['path'] = trailingslashit( $redirect['path'] ) . $wp_rewrite->index . '/';
			}

			if ( ! empty( $addl_path ) ) {
				$redirect['path'] = trailingslashit( $redirect['path'] ) . $addl_path;
			}

			$redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
		}

		if ( 'wp-register.php' === basename( $redirect['path'] ) ) {
			if ( is_multisite() ) {
				/** This filter is documented in wp-login.php */
				$redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
			} else {
				$redirect_url = wp_registration_url();
			}

			wp_redirect( $redirect_url, 301 );
			die();
		}
	}

	$redirect['query'] = preg_replace( '#^??&*?#', '', $redirect['query'] );

	// Tack on any additional query vars.
	if ( $redirect_url && ! empty( $redirect['query'] ) ) {
		parse_str( $redirect['query'], $_parsed_query );
		$redirect = parse_url( $redirect_url );

		if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
			parse_str( $redirect['query'], $_parsed_redirect_query );

			if ( empty( $_parsed_redirect_query['name'] ) ) {
				unset( $_parsed_query['name'] );
			}
		}

		$_parsed_query = array_combine(
			rawurlencode_deep( array_keys( $_parsed_query ) ),
			rawurlencode_deep( array_values( $_parsed_query ) )
		);

		$redirect_url = add_query_arg( $_parsed_query, $redirect_url );
	}

	if ( $redirect_url ) {
		$redirect = parse_url( $redirect_url );
	}

	// www.example.com vs. example.com
	$user_home = parse_url( home_url() );

	if ( ! empty( $user_home['host'] ) ) {
		$redirect['host'] = $user_home['host'];
	}

	if ( empty( $user_home['path'] ) ) {
		$user_home['path'] = '/';
	}

	// Handle ports.
	if ( ! empty( $user_home['port'] ) ) {
		$redirect['port'] = $user_home['port'];
	} else {
		unset( $redirect['port'] );
	}

	// Trailing /index.php.
	$redirect['path'] = preg_replace( '|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path'] );

	$punctuation_pattern = implode(
		'|',
		array_map(
			'preg_quote',
			array(
				' ',
				'%20',  // Space.
				'!',
				'%21',  // Exclamation mark.
				'"',
				'%22',  // Double quote.
				"'",
				'%27',  // Single quote.
				'(',
				'%28',  // Opening bracket.
				')',
				'%29',  // Closing bracket.
				',',
				'%2C',  // Comma.
				'.',
				'%2E',  // Period.
				';',
				'%3B',  // Semicolon.
				'{',
				'%7B',  // Opening curly bracket.
				'}',
				'%7D',  // Closing curly bracket.
				'%E2%80%9C', // Opening curly quote.
				'%E2%80%9D', // Closing curly quote.
			)
		)
	);

	// Remove trailing spaces and end punctuation from the path.
	$redirect['path'] = preg_replace( "#($punctuation_pattern)+$#", '', $redirect['path'] );

	if ( ! empty( $redirect['query'] ) ) {
		// Remove trailing spaces and end punctuation from certain terminating query string args.
		$redirect['query'] = preg_replace( "#((^|&)(p|page_id|cat|tag)=[^&]*?)($punctuation_pattern)+$#", '$1', $redirect['query'] );

		// Clean up empty query strings.
		$redirect['query'] = trim( preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query'] ), '&' );

		// Redirect obsolete feeds.
		$redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );

		// Remove redundant leading ampersands.
		$redirect['query'] = preg_replace( '#^??&*?#', '', $redirect['query'] );
	}

	// Strip /index.php/ when we're not using PATHINFO permalinks.
	if ( ! $wp_rewrite->using_index_permalinks() ) {
		$redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
	}

	// Trailing slashes.
	if ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks()
		&& ! is_404() && ( ! is_front_page() || is_front_page() && get_query_var( 'paged' ) > 1 )
	) {
		$user_ts_type = '';

		if ( get_query_var( 'paged' ) > 0 ) {
			$user_ts_type = 'paged';
		} else {
			foreach ( array( 'single', 'category', 'page', 'day', 'month', 'year', 'home' ) as $type ) {
				$func = 'is_' . $type;
				if ( call_user_func( $func ) ) {
					$user_ts_type = $type;
					break;
				}
			}
		}

		$redirect['path'] = user_trailingslashit( $redirect['path'], $user_ts_type );
	} elseif ( is_front_page() ) {
		$redirect['path'] = trailingslashit( $redirect['path'] );
	}

	// Remove trailing slash for robots.txt or sitemap requests.
	if ( is_robots()
		|| ! empty( get_query_var( 'sitemap' ) ) || ! empty( get_query_var( 'sitemap-stylesheet' ) )
	) {
		$redirect['path'] = untrailingslashit( $redirect['path'] );
	}

	// Strip multiple slashes out of the URL.
	if ( strpos( $redirect['path'], '//' ) > -1 ) {
		$redirect['path'] = preg_replace( '|/+|', '/', $redirect['path'] );
	}

	// Always trailing slash the Front Page URL.
	if ( trailingslashit( $redirect['path'] ) === trailingslashit( $user_home['path'] ) ) {
		$redirect['path'] = trailingslashit( $redirect['path'] );
	}

	$original_host_low = strtolower( $original['host'] );
	$redirect_host_low = strtolower( $redirect['host'] );

	// Ignore differences in host capitalization, as this can lead to infinite redirects.
	// Only redirect no-www <=> yes-www.
	if ( $original_host_low === $redirect_host_low
		|| ( 'www.' . $original_host_low !== $redirect_host_low
			&& 'www.' . $redirect_host_low !== $original_host_low )
	) {
		$redirect['host'] = $original['host'];
	}

	$compare_original = array( $original['host'], $original['path'] );

	if ( ! empty( $original['port'] ) ) {
		$compare_original[] = $original['port'];
	}

	if ( ! empty( $original['query'] ) ) {
		$compare_original[] = $original['query'];
	}

	$compare_redirect = array( $redirect['host'], $redirect['path'] );

	if ( ! empty( $redirect['port'] ) ) {
		$compare_redirect[] = $redirect['port'];
	}

	if ( ! empty( $redirect['query'] ) ) {
		$compare_redirect[] = $redirect['query'];
	}

	if ( $compare_original !== $compare_redirect ) {
		$redirect_url = $redirect['scheme'] . '://' . $redirect['host'];

		if ( ! empty( $redirect['port'] ) ) {
			$redirect_url .= ':' . $redirect['port'];
		}

		$redirect_url .= $redirect['path'];

		if ( ! empty( $redirect['query'] ) ) {
			$redirect_url .= '?' . $redirect['query'];
		}
	}

	if ( ! $redirect_url || $redirect_url === $requested_url ) {
		return;
	}

	// Hex encoded octets are case-insensitive.
	if ( false !== strpos( $requested_url, '%' ) ) {
		if ( ! function_exists( 'lowercase_octets' ) ) {
			/**
			 * Converts the first hex-encoded octet match to lowercase.
			 *
			 * @since 3.1.0
			 * @ignore
			 *
			 * @param array $matches Hex-encoded octet matches for the requested URL.
			 * @return string Lowercased version of the first match.
			 */
			function lowercase_octets( $matches ) {
				return strtolower( $matches[0] );
			}
		}

		$requested_url = preg_replace_callback( '|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url );
	}

	if ( $redirect_obj instanceof WP_Post ) {
		$post_status_obj = get_post_status_object( get_post_status( $redirect_obj ) );
		/*
		 * Unset the redirect object and URL if they are not readable by the user.
		 * This condition is a little confusing as the condition needs to pass if
		 * the post is not readable by the user. That's why there are ! (not) conditions
		 * throughout.
		 */
		if (
			// Private post statuses only redirect if the user can read them.
			! (
				$post_status_obj->private &&
				current_user_can( 'read_post', $redirect_obj->ID )
			) &&
			// For other posts, only redirect if publicly viewable.
			! is_post_publicly_viewable( $redirect_obj )
		) {
			$redirect_obj = false;
			$redirect_url = false;
		}
	}

	/**
	 * Filters the canonical redirect URL.
	 *
	 * Returning false to this filter will cancel the redirect.
	 *
	 * @since 2.3.0
	 *
	 * @param string $redirect_url  The redirect URL.
	 * @param string $requested_url The requested URL.
	 */
	$redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );

	// Yes, again -- in case the filter aborted the request.
	if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) === strip_fragment_from_url( $requested_url ) ) {
		return;
	}

	if ( $do_redirect ) {
		// Protect against chained redirects.
		if ( ! redirect_canonical( $redirect_url, false ) ) {
			wp_redirect( $redirect_url, 301 );
			exit;
		} else {
			// Debug.
			// die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
			return;
		}
	} else {
		return $redirect_url;
	}
}

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