Routing

One fundamental feature of zend-expressive is that it provides mechanisms for implementing dynamic routing, a feature required in most modern web applications. As an example, you may want to allow matching both a resource, as well as individual items of that resource:

  • /books might return a collection of books
  • /books/zend-expressive might return the individual book identified by "zend-expressive".

Expressive does not provide routing on its own; you must choose a routing adapter that implements Zend\Expressive\Router\RouterInterface and provide it to the Application instance. This allows you to choose the router with the capabilities that best match your own needs, while still providing a common abstraction for defining and aggregating routes and their related middleware.

Retrieving matched parameters

Routing enables the ability to match dynamic path segments (or other criteria). Typically, you will want access to the values matched. The routing middleware injects any matched parameters as returned by the underlying router into the request as attributes.

In the example above, let's assume the route was defined as /books/:id, where id is the name of the dynamic segment. This means that in the middleware invoked for this route, you can fetch the id attribute to discover what was matched:

$id = $request->getAttribute('id');

URI generation

Because routers have knowledge of the various paths they can match, they are also typically used within applications to generate URIs to other application resources. Expressive provides this capability in the RouterInterface, either delegating to the underlying router implementations or providing a compatible implementation of its own.

At it's most basic level, you call the generateUri() method with a route name and any substitutions you want to make:

$uri = $router->generateUri('book', ['id' => 'zend-expressive']);

Supported implementations

Expressive currently ships with adapters for the following routers: