Embryo Middleware

Simple dispatcher (PSR-15 server request handler) for a queue of PSR-15 middleware entries. Request handlers and middleware components are a fundamental part of any web application. Server side code receives a request message, processes it, and produces a response message. HTTP middleware is a way to move common request and response processing away from the application layer.

Requirements

• PHP >= 7.1
• A PSR-7 http message implementation and PSR-17 http factory implementation (ex. Embryo-Http)

Installation

Using Composer:

$ composer require davidecesarano/embryo-middleware

Usage

The RequestHandler is a container for a queue of PSR-15 middleware. It takes three methods:

• the method add add a middleware to the end of the queue.
• the method prepend add a middleware to the beginning of the queue.
• the method dispatch requires two arguments, a ServerRequest object and a Response object (used by terminator to return an empty response).

Set ServerRequest and Response

Create ServerRequest and Response objects.

use Embryo\Http\Server\RequestHandler;
use Embryo\Http\Factory\{ServerRequestFactory, ResponseFactory};
use Middlewares\{Uuid, ResponseTime};
use Psr\Http\Message\ServerRequestInterface;

// PSR-7 implementation
$request = (new ServerRequestFactory)->createServerRequestFromServer();
$response = (new ResponseFactory)->createResponse(200);

Add middleware

Create a queue of PSR-15 middleware with the add method or constructor. The add (and prepend) method must be a string or a instance of MiddlewareInterface. In constructor you may create a queue with array of string or instance of MiddlewareInterface.

In this example we use two PSR-15 compatible middleware: Uuid Middleware and ResponseTime Middleware.

// PSR-15 MiddlewareInterface implementation
$middleware = new RequestHandler([
    Uuid::class,
    ResponseTime::class
]);
$response = $middleware->dispatch($request, $response);

Result

The dispatch produces a response messages.

echo 'X-Response-Time: ' . $response->getHeaderLine('X-Response-Time').'<br/>';
echo 'X-Uuid: ' . $response->getHeaderLine('X-Uuid').'<br/>';

echo '<pre>';
    print_r($response->getHeaders());
echo '</pre>';

Example

You may quickly test this using the built-in PHP server going to http://localhost:8000.

$ cd example
$ php -S localhost:8000