Creating canonical URLs with custom route-classes - php

Question

I'm trying to implement canonical URLs and combine it with custom route-classes.
The URL-scheme is something like this:
/category-x/article/123
/category-y/article/123
I create a custom route-class extending Zend_Controller_Router_Route_Regex and checks that the article 123 exists and that the URL includes the correct category-name. If article 123 belongs in category-x and the user is accessing category-y I want to redirect to the correct URL.
But the routes does not have any obvious possibility to do this directly. What's the best practice approach here?

Answer 1

I often do this in my action controller. Something like this...
// assuming GET /category-y/article/123
// $article->url is generated, and contains /category-x/article/123
if (this->_request->getRequestUri() != $article->url) {
return $this->_helper->redirector->goToUrl($article->url);
}
In this example, $article->url would need to be generated from your database data. I often use this to verify a correct slug, when I also pull in the object id.
You could also potentially move this to your routing class, if you wanted to use a custom one instead of using Regex (you could subclass it).

Answer 2

I ended up with this solution:
The custom route-class creates the canonical URL in its match()-method like this:
public function match($path, $partial = false) {
$match = parent::match($path, $partial);
if (!empty($match)) {
$article = $this->backend->getArticle($match['articleId']);
if (!$article) {
throw new Zend_Controller_Router_Exception('Article does not exist', 404);
}
$match['canonicalUrl'] = $this->assemble(array(
'title' => $article->getTitle(),
'articleId' => $article->getId()
));
}
return $match;
}
$article is populated inside match() if the parent::match() returns array.
I've created a front controller plugin which hooks on the routeShutdown() like this:
public function routeShutdown(Zend_Controller_Request_Abstract $request) {
if ($request->has('canonicalUrl')){
$canonicalUrl = $request->getBaseUrl() . '/' . $request->get('canonicalUrl');
if ($canonicalUrl != $request->getRequestUri()) {
$this->getResponse()->setRedirect($canonicalUrl, 301);
}
}
}
It simply checks if the route(custom or native Zend) created a canonical URL and if the requested URL does not match, redirect to the correct canonical URL.