README

Purpose

The purpose of the library is to deliver consistent interface for different versions of http-interop/http-middleware which implements Draft of PSR-15 HTTP Middleware.

Many projects currently use different version of library http-interop/http-middleware and updating to newest version requires usually major release. The library lets consumers of your component decide what version of http-interop/http-middleware they want to use and allow them to migrate to the latest version at any time.

Usage

Your middleware should implement interface Webimpress\HttpMiddlewareCompatibility\MiddlewareInterface, and for delegator/request handler you should use interface Webimpress\HttpMiddlewareCompatibility\HandlerInterface.

<?php

namespace MyNamespace;

use Psr\Http\Message\ServerRequestInterface;
use Webimpress\HttpMiddlewareCompatibility\HandlerInterface;
use Webimpress\HttpMiddlewareCompatibility\MiddlewareInterface;

class MyMiddleware implements MiddlewareInterface
{
    public function process(ServerRequestInterface $request, HandlerInterface $handler)
    {
        // ...
    }
}

Both interfaces are just aliases. It allows your middleware to work with currently installed version of http-interop/http-middleware library.

Delegate/Handler method

The method name was changed across the different versions of http-interop/http-middleware. First the method was called next (release 0.1.1), then process (from 0.2 - 0.4.1) and then handle (in 0.5.0). To accomplish all of them we provide constant Webimpress\HttpMiddlewareCompatibility\HANDLER_METHOD, which has appropriate value depends on used version of http-middleware. Here is an example how you can use it in your middleware:

<?php

namespace MyNamespace;

use Psr\Http\Message\ServerRequestInterface;
use Webimpress\HttpMiddlewareCompatibility\HandlerInterface;
use Webimpress\HttpMiddlewareCompatibility\MiddlewareInterface;

use const Webimpress\HttpMiddlewareCompatibility\HANDLER_METHOD;

class MyMiddleware implements MiddlewareInterface
{
    public function process(ServerRequestInterface $request, HandlerInterface $handler)
    {
        return $handler->{HANDLER_METHOD}($request);
    }
}

That's it! Now consumers of your component can decide what version of http-interop/http-middleware they want to use.