HTTP Discovery

Package for automatic discovery of available implementations providing HTTP functionality. Allows for fast switching between different implementations with minimal effort.

Automatic discovery of HTTP Factories and HTTP Clients is supported.

By default, the following implementations can be discovered:

HTTP Factory

• Guzzle
• Zend Diactoros
• Slim
• Nyholm
• Sunrise

HTTP Client

• Guzzle

Additional implementations can be registered.

Install

composer require http-interop/http-factory-discovery

Usage

HTTP Factory

use Http\Factory\Discovery\HttpFactory;

/** @var \Psr\Http\Message\RequestFactoryInterface */
$requestFactory = HttpFactory::requestFactory();

/** @var \Psr\Http\Message\ResponseFactoryInterface */
$responseFactory = HttpFactory::responseFactory();

/** @var \Psr\Http\Message\ServerRequestFactoryInterface */
$serverRequestFactory = HttpFactory::serverRequestFactory();

/** @var \Psr\Http\Message\StreamFactoryInterface */
$streamFactory = HttpFactory::streamFactory();

/** @var \Psr\Http\Message\UriFactoryInterface */
$uriFactory = HttpFactory::uriFactory();

/** @var \Psr\Http\Message\UploadedFileFactoryInterface */
$uploadedFileFactory = HttpFactory::uploadedFileFactory();

HTTP Client

use Http\Factory\Discovery\HttpClient;

/** @var \Psr\Http\Client\ClientInterface */
$client = HttpClient::client();

Best Practices

Because this package acts as a service locator it should be used to supplement dependency injection.

HTTP Factory

A prime example for using HTTP Factories would be when writing PSR-15 middleware:

namespace Acme\Middleware;

use Http\Factory\Discovery\HttpFactory;
use Psr\Http\Message\ResponseFactoryInterface;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Psr\Http\Message\StreamFactoryInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface as Handler;

class CatchErrors extends MiddlewareInterface
{
    /** @var ResponseFactoryInterface */
    private $responseFactory;

    /** @var StreamFactoryInterface */
    private $streamFactory;

    public function __construct(
        ResponseFactoryInterface $responseFactory = null,
        StreamFactoryInterface $streamFactory = null
    ) {
        $this->responseFactory = $responseFactory ?? HttpFactory::responseFactory();
        $this->streamFactory = $streamFactory ?? HttpFactory::streamFactory();
    }

    public function process(Request $request, Handler $handler): Response
    {
        try {
            return $handler->handle($request);
        } catch (\Throwable $error) {
            $stream = $this->streamFactory->createStream($e->getMessage());

            $response = $this->responseFactory->createResponse(500);
            $response = $response->withHeader('content-type', 'text/plain');
            $response = $response->withBody($stream);

            return $response;
        }
    }
}

HTTP Client

An example for using both HTTP Client and HTTP Factories would be when writing functionality sending HTTP requests:

namespace Acme;

use Http\Factory\Discovery\HttpClient;
use Http\Factory\Discovery\HttpFactory;
use Psr\Http\Client\ClientInterface;
use Psr\Http\Message\RequestFactoryInterface;

class Api
{
    /** @var ClientInterface */
    private $client;

    /** @var RequestFactoryInterface */
    private $requestFactory;

    public function __construct(
        ClientInterface $client = null,
        RequestFactoryInterface $requestFactory = null
    ) {
        $this->client = $client ?? HttpClient::client();
        $this->requestFactory = $requestFactory ?? HttpFactory::requestFactory();
    }

    public function query(): string
    {
        $request = $this->requestFactory->createRequest('GET', 'http://acme.com/api');

        return $this->client->sendRequest($request)->getBody()->getContents();
    }
}

Registering Additional Implementations

Additional implementations can be registered:

HTTP Factory

use Acme\RequestFactory;
use Http\Factory\Discovery\FactoryLocator;
use Psr\Http\Message\RequestFactoryInterface;

FactoryLocator::register(RequestFactoryInterface::class, RequestFactory::class);

HTTP Client

use Acme\Client;
use Http\Factory\Discovery\ClientLocator;
use Psr\Http\Client\ClientInterface;

ClientLocator::register(ClientInterface::class, Client::class);

Implementations can also be unregistered, if you prefer not to use them:

HTTP Factory

use Http\Factory\Discovery\FactoryLocator;
use Http\Factory\Guzzle\UriFactory;
use Psr\Http\Message\UriFactoryInterface;

FactoryLocator::unregister(UriFactoryInterface::class, UriFactory::class);

HTTP Client

use Http\Factory\Discovery\ClientLocator;
use Http\Adapter\Guzzle6\Client;
use Psr\Http\Client\ClientInterface;

ClientLocator::unregister(ClientInterface::class, Client::class);

Clearing Cache

The cache of discovered implementations can be cleared:

HTTP Factory

use Http\Factory\Discovery\HttpFactory;
use Psr\Http\Message\UriFactoryInterface;

// Clear a single interface
HttpFactory::clearCache(UriFactoryInterface::class);

// Clear all interfaces
HttpFactory::clearCache();

HTTP Client

use Http\Factory\Discovery\HttpClient;
use Psr\Http\Client\ClientInterface;

// Clear a single interface
HttpClient::clearCache(ClientInterface::class);

// Clear all interfaces
HttpClient::clearCache();

Note: Cache is automatically cleared when FactoryLocator::unregister() or ClientLocator::unregister() is called.