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:
/booksmight return a collection of books/books/zend-expressivemight 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: