10.5. The Standard Router

10.5.1. Introduction

Zend_Controller_Router_Rewrite is the standard framework router. Routing is the process of taking a URI endpoint (that part of the URI which comes after the base URL) and decomposing it into parameters to determine which module, controller, and action of that controller should receive the request. This values of the module, controller, action and other parameters are packaged into a Zend_Controller_Request_Http object which is then processed by Zend_Controller_Dispatcher_Standard. Routing occurs only once: when the request is initially received and before the first controller is dispatched.

Zend_Controller_Router_Rewrite is designed to allow for mod_rewrite-like functionality using pure php structures. It is very loosely based on Ruby on Rails routing and does not require any prior knowledge of webserver URL rewriting. It is designed to work with a single Apache mod_rewrite rule (one of):

RewriteEngine on
RewriteRule !\.(js|ico|gif|jpg|png|css|html)$ index.php

        

or (preferred):

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ - [NC,L]
RewriteRule ^.*$ index.php [NC,L]

        

The rewrite router can also be used with the IIS webserver (versions <= 7.0) if Isapi_Rewrite has been installed as an Isapi extension with the following rewrite rule:

RewriteRule ^[\w/\%]*(?:\.(?!(?:js|ico|gif|jpg|png|css|html)$)[\w\%]*$)? /index.php [I]

        
[Note] IIS Isapi_Rewrite

When using IIS, $_SERVER['REQUEST_URI'] will either not exist, or be set as an empty string. In this case, Zend_Controller_Request_Http will attempt to use the $_SERVER['HTTP_X_REWRITE_URL'] value set by the Isapi_Rewrite extension.

IIS 7.0 introduces a native URL rewriting module, and it can be configured as follows:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
     <system.webServer>
         <rewrite>
             <rules>
                 <rule name="Imported Rule 1" stopProcessing="true">
                     <match url="^.*$" />
                     <conditions logicalGrouping="MatchAny">
                         <add input="{REQUEST_FILENAME}" 
                             matchType="IsFile" pattern="" 
                             ignoreCase="false" />
                         <add input="{REQUEST_FILENAME}" 
                             matchType="IsDirectory" 
                             pattern="" ignoreCase="false" />
                     </conditions>
                     <action type="None" />
                 </rule>
                 <rule name="Imported Rule 2" stopProcessing="true">
                     <match url="^.*$" />
                     <action type="Rewrite" url="index.php" />
                 </rule>
             </rules>
         </rewrite>
     </system.webServer>
</configuration>

If using Lighttpd, the following rewrite rule is valid:

url.rewrite-once = (
    ".*\?(.*)$" => "/index.php?$1",
    ".*\.(js|ico|gif|jpg|png|css|html)$" => "$0",
    "" => "/index.php"
)

        

10.5.2. Using a router

To properly use the rewrite router you have to instantiate it, add some user defined routes and inject it into the controller. The following code illustrates the procedure:

// Create a router

$router = $ctrl->getRouter(); // returns a rewrite router by default
$router->addRoute(
    'user',
    new Zend_Controller_Router_Route('user/:username',
                                     array('controller' => 'user',
                                           'action' => 'info'))
);

        

10.5.3. Basic Rewrite Router operation

The heart of the RewriteRouter is the definition of user defined routes. Routes are added by calling the addRoute method of RewriteRouter and passing in a new instance of a class implementing Zend_Controller_Router_Route_Interface. Eg.:

$router->addRoute('user',
                  new Zend_Controller_Router_Route('user/:username'));

        

Rewrite Router comes with five basic types of routes (one of which is special):

Routes may be used numerous times to create a chain or user defined application routing schema. You may use any number of routes in any configuration, with the exception of the Module route, which should rather be used once and probably as the most generic route (i.e., as a default). Each route will be described in greater detail later on.

The first parameter to addRoute is the name of the route. It is used as a handle for getting the routes out of the router (e.g., for URL generation purposes). The second parameter being the route itself.

[Note] Note

The most common use of the route name is through the means of Zend_View url helper:

<a href=
"<?= $this->url(array('username' => 'martel'), 'user') ?>">Martel</a>

            

Which would result in the href: user/martel.

Routing is a simple process of iterating through all provided routes and matching its definitions to current request URI. When a positive match is found, variable values are returned from the Route instance and are injected into the Zend_Controller_Request object for later use in the dispatcher as well as in user created controllers. On a negative match result, the next route in the chain is checked.

[Note] Reverse matching

Routes are matched in reverse order so make sure your most generic routes are defined first.

[Note] Returned values

Values returned from routing come from URL parameters or user defined route defaults. These variables are later accessible through the Zend_Controller_Request::getParam() or Zend_Controller_Action::_getParam() methods.

There are three special variables which can be used in your routes - 'module', 'controller' and 'action'. These special variables are used by Zend_Controller_Dispatcher to find a controller and action to dispatch to.

[Note] Special variables

The names of these special variables may be different if you choose to alter the defaults in Zend_Controller_Request_Http by means of the setControllerKey and setActionKey methods.

10.5.4. Default routes

Zend_Controller_Router_Rewrite comes preconfigured with a default route, which will match URIs in the shape of controller/action. Additionally, a module name may be specified as the first path element, allowing URIs of the form module/controller/action. Finally, it will also match any additional parameters appended to the URI by default - controller/action/var1/value1/var2/value2.

Some examples of how such routes are matched:

// Assuming the following:
$ctrl->setControllerDirectory(
    array(
        'default' => '/path/to/default/controllers',
        'news'    => '/path/to/news/controllers',
        'blog'    => '/path/to/blog/controllers'
    )
);

Module only:
http://example/news
    module == news

Invalid module maps to controller name:
http://example/foo
    controller == foo

Module + controller:
http://example/blog/archive
    module     == blog
    controller == archive

Module + controller + action:
http://example/blog/archive/list
    module     == blog
    controller == archive
    action     == list

Module + controller + action + params:
http://example/blog/archive/list/sort/alpha/date/desc
    module     == blog
    controller == archive
    action     == list
    sort       == alpha
    date       == desc

        

The default route is simply a Zend_Controller_Router_Route_Module object stored under the name (index) of 'default' in RewriteRouter. It's created more-or-less like below:

$compat = new Zend_Controller_Router_Route_Module(array(),
                                                  $dispatcher,
                                                  $request);
$this->addRoute('default', $compat);

        

If you do not want this particular default route in your routing schema, you may override it by creating your own 'default' route (i.e., storing it under the name of 'default') or removing it altogether by using removeDefaultRoutes():

// Remove any default routes
$router->removeDefaultRoutes();

        

10.5.5. Base URL and subdirectories

The rewrite router can be used in subdirectories (e.g., http://domain.com/~user/application-root/) in which case the base URL of the application (/~user/application-root) should be automatically detected by Zend_Controller_Request_Http and used accordingly.

Should the base URL be detected incorrectly you can override it with your own base path by using Zend_Controller_Request_Http and calling the setBaseUrl() method (see Section 10.4.2.2, “Base Url and Subdirectories”):

$request->setBaseUrl('/~user/application-root/');

        

10.5.6. Global parameters

You can set global parameters in a router which are automatically supplied to a route when assembling through the setGlobalParam. If a global parameter is set but also given to the assemble method directly, the user parameter overrides the global parameter. You can set a global parameter this way:

$router->setGlobalParam('lang', 'en');

        

10.5.7. Route Types

10.5.7.1. Zend_Controller_Router_Route

Zend_Controller_Router_Route is the standard framework route. It combines ease of use with flexible route definition. Each route consists primarily of URL mapping (of static and dynamic parts (variables)) and may be initialized with defaults as well as with variable requirements.

Let's imagine our fictional application will need some informational page about the content authors. We want to be able to point our web browsers to http://domain.com/author/martel to see the information about this "martel" guy. And the route for such functionality could look like:

$route = new Zend_Controller_Router_Route(
    'author/:username',
    array(
        'controller' => 'profile',
        'action'     => 'userinfo'
    )
);

$router->addRoute('user', $route);

    

The first parameter in the Zend_Controller_Router_Route constructor is a route definition that will be matched to a URL. Route definitions consist of static and dynamic parts separated by the slash ('/') character. Static parts are just simple text: author. Dynamic parts, called variables, are marked by prepending a colon to the variable name: :username.

[Note] Character usage

The current implementation allows you to use any character (except a slash) as a variable identifier, but it is strongly recommended that one uses only characters that are valid for PHP variable identifiers. Future implementations may alter this behaviour, which could result in hidden bugs in your code.

This example route should be matched when you point your browser to http://domain.com/author/martel, in which case all its variables will be injected to the Zend_Controller_Request object and will be accessible in your ProfileController. Variables returned by this example may be represented as an array of the following key and value pairs:

$values = array(
    'username'   => 'martel',
    'controller' => 'profile',
    'action'     => 'userinfo'
);

    

Later on, Zend_Controller_Dispatcher_Standard should invoke the userinfoAction() method of your ProfileController class (in the default module) based on these values. There you will be able to access all variables by means of the Zend_Controller_Action::_getParam() or Zend_Controller_Request::getParam() methods:

public function userinfoAction()
{
    $request = $this->getRequest();
    $username = $request->getParam('username');

    $username = $this->_getParam('username');
}

    

Route definition can contain one more special character - a wildcard - represented by '*' symbol. It is used to gather parameters similarly to the default Module route (var => value pairs defined in the URI). The following route more-or-less mimics the Module route behavior:

$route = new Zend_Controller_Router_Route(
    ':module/:controller/:action/*',
    array('module' => 'default')
);
$router->addRoute('default', $route);

    
10.5.7.1.1. Variable defaults

Every variable in the route can have a default and this is what the second parameter of the Zend_Controller_Router_Route constructor is used for. This parameter is an array with keys representing variable names and with values as desired defaults:

$route = new Zend_Controller_Router_Route(
    'archive/:year',
    array('year' => 2006)
);
$router->addRoute('archive', $route);

        

The above route will match URLs like http://domain.com/archive/2005 and http://example.com/archive. In the latter case the variable year will have an initial default value of 2006.

This example will result in injecting a year variable to the request object. Since no routing information is present (no controller and action parameters are defined), the application will be dispatched to the default controller and action method (which are both defined in Zend_Controller_Dispatcher_Abstract). To make it more usable, you have to provide a valid controller and a valid action as the route's defaults:

$route = new Zend_Controller_Router_Route(
    'archive/:year',
    array(
        'year'       => 2006,
        'controller' => 'archive',
        'action'     => 'show'
    )
);
$router->addRoute('archive', $route);

        

This route will then result in dispatching to the method showAction() of the class ArchiveController.

10.5.7.1.2. Variable requirements

One can add a third parameter to the Zend_Controller_Router_Route constructor where variable requirements may be set. These are defined as parts of a regular expression:

$route = new Zend_Controller_Router_Route(
    'archive/:year',
    array(
        'year'       => 2006,
        'controller' => 'archive',
        'action'     => 'show'
    ),
    array('year' => '\d+')
);
$router->addRoute('archive', $route);

        

With a route defined like above, the router will match it only when the year variable will contain numeric data, eg. http://domain.com/archive/2345. A URL like http://example.com/archive/test will not be matched and control will be passed to the next route in the chain instead.

10.5.7.2. Zend_Controller_Router_Route_Static

The examples above all use dynamic routes -- routes that contain patterns to match against. Sometimes, however, a particular route is set in stone, and firing up the regular expression engine would be an overkill. The answer to this situation is to use static routes:

$route = new Zend_Controller_Router_Route_Static(
    'login',
    array('controller' => 'auth', 'action' => 'login')
);
$router->addRoute('login', $route);

    

Above route will match a URL of http://domain.com/login, and dispatch to AuthController::loginAction().

10.5.7.3. Zend_Controller_Router_Route_Regex

In addition to the default and static route types, a Regular Expression route type is available. This route offers more power and flexibility over the others, but at a slight cost of complexity. At the same time, it should be faster than the standard Route.

Like the standard route, this route has to be initialized with a route definition and some defaults. Let's create an archive route as an example, similar to the previously defined one, only using the Regex route this time:

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)',
    array(
        'controller' => 'archive',
        'action'     => 'show'
    )
);
$router->addRoute('archive', $route);

    

Every defined regex subpattern will be injected to the request object. With our above example, after successful matching http://domain.com/archive/2006, the resulting value array may look like:

$values = array(
    1            => '2006',
    'controller' => 'archive',
    'action'     => 'show'
);

    
[Note] Note

Leading and trailing slashes are trimmed from the URL in the Router prior to a match. As a result, matching the URL http://domain.com/foo/bar/, would involve a regex of foo/bar, and not /foo/bar.

[Note] Note

Line start and line end anchors ('^' and '$', respectively) are automatically pre- and appended to all expressions. Thus, you should not use these in your regular expressions, and you should match the entire string.

[Note] Note

This route class uses the # character for a delimiter. This means that you will need to escape hash characters ('#') but not forward slashes ('/') in your route definitions. Since the '#' character (named anchor) is rarely passed to the webserver, you will rarely need to use that character in your regex.

You can get the contents of the defined subpatterns the usual way:

public function showAction()
{
    $request = $this->getRequest();
    $year    = $request->getParam(1); // $year = '2006';
}

    
[Note] Note

Notice the key is an integer (1) instead of a string ('1').

This route will not yet work exactly the same as its standard route counterpart since the default for 'year' is not yet set. And what may not yet be evident is that we will have a problem with a trailing slash even if we declare a default for the year and make the subpattern optional. The solution is to make the whole year part optional along with the slash but catch only the numeric part:

$route = new Zend_Controller_Router_Route_Regex(
    'archive(?:/(\d+))?',
    array(
        1            => '2006',
        'controller' => 'archive',
        'action'     => 'show'
    )
);
$router->addRoute('archive', $route);

    

Now let's get to the problem you have probably noticed on your own by now. Using integer based keys for parameters is not an easily manageable solution and may be potentially problematic in the long run. And that's where the third parameter comes in. This parameter is an associative array that represents a map of regex subpatterns to parameter named keys. Let's work on our easier example:

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)',
    array(
        'controller' => 'archive',
        'action' => 'show'
    ),
    array(
        1 => 'year'
    )
);
$router->addRoute('archive', $route);

    

This will result in following values injected into Request:

$values = array(
    'year'       => '2006',
    'controller' => 'archive',
    'action'     => 'show'
);

    

The map may be defined in either direction to make it work in any environment. Keys may contain variable names or subpattern indexes:

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)',
    array( ... ),
    array(1 => 'year')
);

// OR

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)',
    array( ... ),
    array('year' => 1)
);

    
[Note] Note

Subpattern keys have to be represented by integers.

Notice that the numeric index in Request values is now gone and a named variable is shown in its place. Of course you can mix numeric and named variables if you wish:

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)/page/(\d+)',
    array( ... ),
    array('year' => 1)
);

    

Which will result in mixed values available in the Request. As an example, the URL http://domain.com/archive/2006/page/10 will result in following values:

$values = array(
    'year'       => '2006',
    2            => 10,
    'controller' => 'archive',
    'action'     => 'show'
);

    

Since regex patterns are not easily reversed, you will need to prepare a reverse URL if you wish to use a URL helper or even an assemble method of this class. This reversed path is represented by a string parsable by sprintf() and is defined as a fourth construct parameter:

$route = new Zend_Controller_Router_Route_Regex(
    'archive/(\d+)',
    array( ... ),
    array('year' => 1),
    'archive/%s'
);

    

All of this is something which was already possible by the means of a standard route object, so where's the benefit in using the Regex route, you ask? Primarily, it allows you to describe any type of URL without any restrictions. Imagine you have a blog and wish to create URLs like: http://domain.com/blog/archive/01-Using_the_Regex_Router.html, and have it decompose the last path element, 01-Using_the_Regex_Router.html, into an article ID and article title/description; this is not possible with the standard route. With the Regex route, you can do something like the following solution:

$route = new Zend_Controller_Router_Route_Regex(
    'blog/archive/(\d+)-(.+)\.html',
    array(
        'controller' => 'blog',
        'action'     => 'view'
    ),
    array(
        1 => 'id',
        2 => 'description'
    ),
    'blog/archive/%d-%s.html'
);
$router->addRoute('blogArchive', $route);

    

As you can see, this adds a tremendous amount of flexibility over the standard route.

10.5.7.4. Zend_Controller_Router_Route_Hostname

Zend_Controller_Router_Route_Hostname is the hostname route of the framework. It works similar to the standard route, but it works on the with the hostname of the called URL instead with the path.

Let's use the example from the standard route and see how it would look like in a hostname based way. Instead of calling the user via a path, we'd want to have a user to be able to call http://martel.users.example.com to see the information about the user "martel":

$hostnameRoute = new Zend_Controller_Router_Route_Hostname(
    ':username.users.example.com',
    array(
        'controller' => 'profile',
        'action'     => 'userinfo'
    )
);

$plainPathRoute = new Zend_Controller_Router_Route_Static('');

$router->addRoute('user', $hostnameRoute->chain($plainPathRoute);

    

The first parameter in the Zend_Controller_Router_Route_Hostname constructor is a route definition that will be matched to a hostname. Route definitions consist of static and dynamic parts separated by the dot ('.') character. Dynamic parts, called variables, are marked by prepending a colon to the variable name: :username. Static parts are just simple text: user.

Hostname routes can, but never should be used as is. The reason behind that is, that a hostname route alone would match any path. So what you have to do is to chain a path route to the hostname route. This is done like in the example by calling $hostnameRoute->chain($pathRoute);. By doing this, $hostnameRoute isn't modified, but a new route (Zend_Controller_Router_Route_Chain) is returned, which can then be given to the router.

[Note] Parameter priority

When chaining routes like the hostname route and the path route together, the parameters of the hostname route have a higher priority than the parameters of the path route. Thus if you define a controller in the hostname and in the path route, the controller of the hostname route will be selected.

10.5.7.4.1. Hostname routes via Zend_Config

To chain hostname routes and path routes together, there is an additional parameter for the configuration called chains. This one is simply a list of routes, which will be chained with the parent route. Neither the parent- nor the child-route will be added directly to the router but only the chained route. The name of the chained route in the router will be the parent route name and the child route name concatenated with a dash (-). A simple config in XML would look like:

<routes>
    <www type="Zend_Controller_Router_Route_Hostname">
        <route>www.example.com</route>
        <chains>
            <index type="Zend_Controller_Router_Route_Static">
                <route></route>
                <defaults module="default" controller="index" action="index" />
            </index>
            <imprint type="Zend_Controller_Router_Route_Static">
                <route>imprint</route>
                <defaults module="default" controller="index" action="index" />
            </imprint>
        </chains>
    </www>
    <users type="Zend_Controller_Router_Route_Hostname">
        <route>users.example.com</route>
        <chains>
            <profile type="Zend_Controller_Router_Route">
                <route>:username</route>
                <defaults module="users" controller="profile" action="index" />
            </index>
        </chains>
    </users>
    <misc type="Zend_Controller_Router_Route_Static">
        <route>misc</route>
    </misc>
</routes>

        

This will result in the three routes www-index, www-imprint and users-profile which will only match based on the hostname and the route misc, which will match with any hostname.

10.5.8. Using Zend_Config with the RewriteRouter

Sometimes it is more convenient to update a configuration file with new routes than to change the code. This is possible via the addConfig() method. Basically, you create a Zend_Config-compatible configuration, and in your code read it in and pass it to the RewriteRouter.

As an example, consider the following INI file:

[production]
routes.archive.route = "archive/:year/*"
routes.archive.defaults.controller = archive
routes.archive.defaults.action = show
routes.archive.defaults.year = 2000
routes.archive.reqs.year = "\d+"

routes.news.type = "Zend_Controller_Router_Route_Static"
routes.news.route = "news"
routes.news.defaults.controller = "news"
routes.news.defaults.action = "list"

routes.archive.type = "Zend_Controller_Router_Route_Regex"
routes.archive.route = "archive/(\d+)"
routes.archive.defaults.controller = "archive"
routes.archive.defaults.action = "show"
routes.archive.map.1 = "year"
; OR: routes.archive.map.year = 1

        

The above INI file can then be read into a Zend_Config object as follows:

$config = new Zend_Config_Ini('/path/to/config.ini', 'production');
$router = new Zend_Controller_Router_Rewrite();
$router->addConfig($config, 'routes');

        

In the above example, we tell the router to use the 'routes' section of the INI file to use for its routes. Each first-level key under that section will be used to define a route name; the above example defines the routes 'archive' and 'news'. Each route then requires, at minimum, a 'route' entry and one or more 'defaults' entries; optionally one or more 'reqs' (short for 'required') may be provided. All told, these correspond to the three arguments provided to a Zend_Controller_Router_Route_Interface object. An option key, 'type', can be used to specify the route class type to use for that particular route; by default, it uses Zend_Controller_Router_Route. In the example above, the 'news' route is defined to use Zend_Controller_Router_Route_Static.

10.5.9. Subclassing the Router

The standard rewrite router should provide most functionality you may need; most often, you will only need to create a new route type in order to provide new or modified functionality over the provided routes.

That said, you may at some point find yourself wanting to use a different routing paradigm. The interface Zend_Controller_Router_Interface provides the minimal information required to create a router, and consists of a single method.

interface Zend_Controller_Router_Interface
{
  /**
   * @param  Zend_Controller_Request_Abstract $request
   * @throws Zend_Controller_Router_Exception
   * @return Zend_Controller_Request_Abstract
   */
  public function route(Zend_Controller_Request_Abstract $request);
}

        

Routing only occurs once: when the request is first received into the system. The purpose of the router is to determine the controller, action, and optional parameters based on the request environment, and then set them in the request. The request object is then passed to the dispatcher. If it is not possible to map a route to a dispatch token, the router should do nothing to the request object.