Customizable router frontName

Question

I have a router like this

<routers>
    <mymodule>
        <use>standard</use>
        <args>
            <module>NSP_MyModule</module>
            <frontName>mymodule</frontName>
        </args>
    </mymodule>     
</routers>

which (in my environment) will be accessable with this URL /magento/mymodule but I want the URL key mymodule to be custamizable through backend. How can I achieve that?

Answer 1

In this excellent post by Alan Storm, I found a hint to a possible solution. You should register your own router. An example can be found in Magento's CMS module.

In the CMS module's config.xml find this section:

<events>
    <controller_front_init_routers>
        <observers>
            <cms>
                <class>Mage_Cms_Controller_Router</class>
                <method>initControllerRouters</method>
            </cms>
        </observers>
    </controller_front_init_routers>
</events>

The method initControllerRouters() registers a new router:

public function initControllerRouters($observer)
{
    /* @var $front Mage_Core_Controller_Varien_Front */
    $front = $observer->getEvent()->getFront();

    $front->addRouter('cms', $this);
}

...that will be iterated in app/code/core/Mage/Core/Controller/Varien/Front.php:

while (!$request->isDispatched() && $i++<100) {
    foreach ($this->_routers as $router) {
        if ($router->match($this->getRequest())) {
            break;
        }
    }
}

The match() method of the CMS-Router contains this code:

$page   = Mage::getModel('cms/page');
$pageId = $page->checkIdentifier($identifier, Mage::app()->getStore()->getId());
if (!$pageId) {
    return false;
}

$request->setModuleName('cms')
    ->setControllerName('page')
    ->setActionName('view')
    ->setParam('page_id', $pageId);

...which leads to the file Cms/controllers/PageController.php. The class inside is named Mage_Cms_PageController and has a method viewAction() that asks for the request's parameter page_id. From here, you can look further at the method Mage::helper('cms/page')->renderPage($this, $pageId).

I think another big problem will be, if the configured frontName matches that of a system frontName, or the frontName defined by another module. I have no idea how this might work out.

Answer 2

In order to achieve this, you need to manually add your dynamic routes to Standard-Router¹ before dispatching of router happens. I will show you how you can achieve this with an example below. Using which, you can implement rest.

You need to listen to the event controller_front_init_routers and add your routes in the observer.

File: app\code\{codePool}\{Namespace}\{Module}\etc\config.xml

<config>
    <global>
        <events>
            <controller_front_init_routers>
                <observers>
                    <add_dynamic_frontnames>
                        <class>namespace_module/observer</class>
                        <method>addDynamicFrontnames</method>
                    </add_dynamic_frontnames>
                </observers>
            </controller_front_init_routers>
        </events>
    </global>
</config>

^{Note : Important. Observer should be inside global scope.}

File : app\code\{codePool}\{Namespace}\{Module}\Model\Observer.php

<?php
class Namespace_Module_Model_Observer
{
    const DYNAMIC_FRONTNAMES = 'sytem/config/path/to/dynamic/routes';

    public function addDynamicFrontnames(Varien_Event_Observer $observer)
    {
        //get front controller
        $front = $observer->getEvent()->getFront();

        //grab request object and standard router
        $request = $front->getRequest();
        $standardRouter = $front->getRouter('standard');

        //grab module and route info using frontname;
        //note:a router with frontname 'mymodule' should be configured in your module
        $drouteName = $standardRouter->getRouteByFrontName('mymodule');
        $dmoduleName = $standardRouter->getModuleByFrontName('mymodule');

        //get dynamic frontnames from system config section
        $_dynamicFrontNames = explode(',',
            Mage::getStoreConfig()->getNode(self::DYNAMIC_FRONTNAMES)
        );

        //add your dynamic frontnames to standard router
        foreach ($_dynamicFrontNames as $frontName) {
            $standardRouter->addModule($frontName, $dmoduleName, $drouteName);
        }

        return $this;
    }

What we are doing here is, we are using Front-Controller² to grab Standard-Router. Then we will collect module-name and router-name using our frontName mymodule. Then set the same module-name and router-name for every dynamic frontname which we collect from the system config section sytem/config/path/to/dynamic/routes. So all the frontnames which you configured from system config section will just behave like mymodule frontname here.

So along with these event setup, you are required to setup a router like this in your config.xml file.

<config>
    <frontend>
        <routers>
            <{router_identifer}>
                <use>standard</use>
                <args>
                    <module>Namspace_Module</module>
                    <frontName>mymodule</frontName>
                </args>
            </{router_identifer}>
        </routers>
    </frontend>
</config>

Also you need to setup a system.xml file to configure your dynamic frontnames and replace the constant DYNAMIC_FRONTNAMES with the the right path in the observer file above.

Hope that makes sense.

---

^{1:Mage_Core_Controller_Varien_Router_Standard}

^{2:Mage_Core_Controller_Varien_Front}