Refactor old page redirector into an extension

code/controllers/ContentController.php

@@ -22,6 +22,8 @@ class ContentController extends Controller {
 
 	protected $dataRecord;
 
+	private static $extensions = array('OldPageRedirector');
+
 	private static $allowed_actions = array(
 		'successfullyinstalled',
 		'deleteinstallfiles', // secured through custom code
@@ -168,31 +170,6 @@ class ContentController extends Controller {
 				'URLSegment' => rawurlencode($action)
 			))->first();
 			if(class_exists('Translatable')) Translatable::enable_locale_filter();
-			
-			// if we can't find a page with this URLSegment try to find one that used to have 
-			// that URLSegment but changed. See ModelAsController->getNestedController() for similiar logic.
-			if(!$child){
-				$child = ModelAsController::find_old_page($action,$this->ID);
-				if($child){
-					$response = new SS_HTTPResponse();
-					$params = $request->getVars();
-					if(isset($params['url'])) unset($params['url']);
-					$response->redirect(
-						Controller::join_links(
-							$child->Link(
-								Controller::join_links(
-									$request->param('ID'), // 'ID' is the new 'URLSegment', everything shifts up one position
-									$request->param('OtherID')
-								)
-							),
-							// Needs to be in separate join links to avoid urlencoding
-							($params) ? '?' . http_build_query($params) : null
-						),
-						301
-					);
-					return $response;
-				}
-			}
 		}
 		
 		// we found a page with this URLSegment.

code/controllers/ModelAsController.php

@@ -7,6 +7,7 @@
  * @subpackage control
  */
 class ModelAsController extends Controller implements NestedController {
+	private static $extensions = array('OldPageRedirector');
 	
 	/**
 	 * Get the appropriate {@link ContentController} for handling a {@link SiteTree} object, link it to the object and
@@ -108,31 +109,6 @@ class ModelAsController extends Controller implements NestedController {
 		if(class_exists('Translatable')) Translatable::enable_locale_filter();
 		
 		if(!$sitetree) {
-			// If a root page has been renamed, redirect to the new location.
-			// See ContentController->handleRequest() for similiar logic.
-			$redirect = self::find_old_page($URLSegment);
-			if($redirect) {
-				$params = $request->getVars();
-				if(isset($params['url'])) unset($params['url']);
-				$this->response = new SS_HTTPResponse();
-				$this->response->redirect(
-					Controller::join_links(
-						$redirect->Link(
-							Controller::join_links(
-								$request->param('Action'), 
-								$request->param('ID'), 
-								$request->param('OtherID')
-							)
-						),
-						// Needs to be in separate join links to avoid urlencoding
-						($params) ? '?' . http_build_query($params) : null
-					),
-					301
-				);
-				
-				return $this->response;
-			}
-			
 			$response = ErrorPage::response_for(404);
 			$this->httpError(404, $response ? $response : 'The requested page could not be found.');
 		}
@@ -148,45 +124,18 @@ class ModelAsController extends Controller implements NestedController {
 	}
 
 	/**
+	 * @deprecated 3.2 Use OldPageRedirector::find_old_page instead
+	 *
 	 * @param string $URLSegment A subset of the url. i.e in /home/contact/ home and contact are URLSegment.
 	 * @param int $parentID The ID of the parent of the page the URLSegment belongs to.
 	 * @return SiteTree
 	 */
-	static public function find_old_page($URLSegment,$parentID = 0, $ignoreNestedURLs = false) {
+	static public function find_old_page($URLSegment, $parent = null, $ignoreNestedURLs = false) {
-		
+		Deprecation::notice('3.2', 'Use OldPageRedirector::find_old_page instead');
-		$useParentIDFilter = SiteTree::config()->nested_urls && $parentID;
+		if ($parent) {
-				
+			$parent = SiteTree::get()->byId($parent);	
-		// First look for a non-nested page that has a unique URLSegment and can be redirected to.
-		if(SiteTree::config()->nested_urls) {
-			$pages = SiteTree::get()->filter("URLSegment", rawurlencode($URLSegment));
-			if($useParentIDFilter) {
-				$pages = $pages->filter("ParentID", (int)$parentID);
 		}
-
+		$url = OldPageRedirector::find_old_page(array($URLSegment), $parent);
-			if($pages && $pages->Count() == 1 && ($page = $pages->First())) {
+		return SiteTree::get_by_link($url);
-				$parent = $page->ParentID ? $page->Parent() : $page;
-				if($parent->isPublished()) return $page;
 	}
-		}
-		
-		// Get an old version of a page that has been renamed.
-		$URLSegmentSQL = Convert::raw2sql(rawurlencode($URLSegment));
-		$query = new SQLQuery (
-			'"RecordID"',
-			'"SiteTree_versions"',
-			"\"URLSegment\" = '$URLSegmentSQL' AND \"WasPublished\" = 1" . ($useParentIDFilter ? ' AND "ParentID" = ' . (int)$parentID : ''),
-			'"LastEdited" DESC',
-			null,
-			null,
-			1
-		);
-		$record = $query->execute()->first();
-		
-		if($record && ($oldPage = DataObject::get_by_id('SiteTree', $record['RecordID']))) {
-			$oldParent = $oldPage->ParentID ? $oldPage->Parent() : $oldPage;
-			// Run the page through an extra filter to ensure that all extensions are applied.
-			if(SiteTree::get_by_link($oldPage->RelativeLink()) && $oldParent->isPublished()) return $oldPage;
-		}
-	}
-	
 }

code/controllers/OldPageRedirector.php

@@ -0,0 +1,91 @@
+<?php
+
+class OldPageRedirector extends Extension {
+
+	/**
+	 * On every URL that generates a 404, we'll capture it here and see if we can
+	 * find an old URL that it should be redirecting to.
+	 *
+	 * @param SS_HTTPResponse $request The request object
+	 */
+	public function onBeforeHTTPError404($request) {
+		// Build up the request parameters
+		$params = array_filter(array_values($request->allParams()), function($v) { return ($v !== NULL); });
+
+		$getvars = $request->getVars();
+		unset($getvars['url']);
+
+		$page = self::find_old_page($params);
+
+		if ($page) {
+			$res = new SS_HTTPResponse();
+			$res->redirect(
+				Controller::join_links(
+					$page,
+					($getvars) ? '?' . http_build_query($getvars) : null
+				), 301);
+			throw new SS_HTTPResponse_Exception($res);
+		}
+	}
+
+	/**
+	 * Attempt to find an old/renamed page from some given the URL as an array
+	 *
+	 * @param array $params The array of URL, e.g. /foo/bar as array('foo', 'bar')
+	 * @param SiteTree $parent The current parent in the recursive flow
+	 * @param boolean $redirect Whether we've found an old page worthy of a redirect
+	 *
+	 * @return string|boolean False, or the new URL
+	 */
+	static public function find_old_page($params, $parent = null, $redirect = false) {
+		$URL = Convert::raw2sql(array_shift($params));
+		if (empty($URL)) { return false; }
+		if ($parent) {
+			$page = SiteTree::get()->filter(array('ParentID' => $parent->ID, 'URLSegment' => $URL))->First();
+		} else {
+			$page = SiteTree::get()->filter(array('URLSegment' => $URL))->First();
+		}
+
+		if (!$page) {
+			// If we haven't found a candidate, lets resort to finding an old page with this URL segment
+			// TODO: Rewrite using ORM syntax
+			$query = new SQLQuery (
+				'"RecordID"',
+				'"SiteTree_versions"',
+				"\"URLSegment\" = '$URL' AND \"WasPublished\" = 1" . ($parent ? ' AND "ParentID" = ' . $parent->ID : ''),
+				'"LastEdited" DESC',
+				null,
+				null,
+				1
+			);
+			$record = $query->execute()->first();
+			if ($record) {
+				$page = SiteTree::get()->byID($record['RecordID']);
+				$redirect = true;
+			}
+		}
+
+		if ($page && $page->canView()) {
+			if (count($params)) {
+				// We have to go deeper!
+				$ret = self::find_old_page($params, $page, $redirect);
+				if ($ret) {
+					// A valid child page was found! We can return it
+					return $ret;
+				} else {
+					// No valid page found.
+					if ($redirect) {
+						// If we had some redirect to be done, lets do it. imagine /foo/action -> /bar/action, we still want this redirect to happen if action isn't a page
+						return $page->Link() . implode('/', $params);
+					}
+				}
+			} else {
+				// We've found the final, end all, page.
+				return $page->Link();
+			}
+		}
+
+		return false;
+	}
+}
+