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Dispatcher

This package provides a Psr-15 dispatcher implementation.

Require php >= 7.0

Installation composer require ellipse/dispatcher

Run tests ./vendor/bin/kahlan

• Using a dispatcher
• Middleware and request handler resolving

Using a dispatcher

This package provides an Ellipse\Dispatcher class allowing to process a Psr-7 request through a Psr-15 middleware queue (First in first out order) before handling it with a Psr-15 request handler in order to create a Psr-7 response.

It is basically a request handler decorator wrapping a middleware queue around a request handler. Its constructor takes two parameters:

• a request handler object implementing Psr\Http\Server\RequestHandlerInterface
• an array containing middleware objects implementing Psr\Http\Server\MiddlewareInterface

The Dispatcher itself implements RequestHandlerInterface so a response is produced by using its ->handle() method with a request. It also means it can be used as the request handler of another Dispatcher. Also, The same Dispatcher can be used multiple times to handle as many requests as needed.

Finally when a value of the given middleware queue is not an implementation of MiddlewareInterface an Ellipse\Dispatcher\Exceptions\MiddlewareTypeException is thrown. Factory decorators can be used to resolve some type of values as middleware.

The Dispatcher class also has a ->with() method taking a MiddlewareInterface as parameter. It returns a new dispatcher with the given middleware wrapped around the current dispatcher. The new middleware will be the first processed by the new dispatcher:

Middleware and request handler resolving

A common practice is to allow callables and class names registered in a container to be used as regular middleware/request handler.

For this purpose this package also provides an Ellipse\DispatcherFactory class implementing Ellipse\DispatcherFactoryInterface, allowing to produce Dispatcher instances. Its __invoke() method takes any value as request handler and an optional middleware queue. An Ellipse\Dispatcher\Exceptions\RequestHandlerTypeException is thrown when the given request handler is not an implementation of RequestHandlerInterface.

This class is not very useful by itself. The point of DispatcherFactory is to be decorated by other factories resolving the given values as Psr-15 implementations before delegating it the dispatcher creation. It is a starting point for such factory decorators (also called resolvers) which ensure the dispatcher creation fails nicely when any value is not resolved as a Psr-15 implementation by any decorator.

Here is an example of callable resolving using the Ellipse\Dispatcher\CallableResolver class from the ellipse/dispatcher-callable package:

Here is some ellipse packages providing resolvers for common resolving scenario:

• ellipse/dispatcher-callable allowing to use callables as Psr-15 middleware/request handlers
• ellipse/dispatcher-container allowing to use Psr-15 middleware/request handler class names using a Psr-11 container
• ellipse/dispatcher-controller allowing to use controller actions as Psr-15 request handlers using a Psr-11 container

Here is an example of a class implementing DispatcherFactoryInterface in case you need to create a custom one: