Using PSR-7 Clients

As noted in the previous section, you can substitute your own HTTP client by implementing the ClientInterface. In this section, we'll demonstrate doing so in order to use a client that is PSR-7-capable.

Responses

zend-feed provides a facility to assist with generating a Zend\Feed\Reader\Response from a PSR-7 ResponseInterface via Zend\Feed\Reader\Http\Psr7ResponseDecorator. As such, if you have a PSR-7-capable client, you can pass the response to this decorator, and immediately return it from your custom client:

return new Psr7ResponseDecorator($psr7Response);

We'll do this with our PSR-7 client.

Guzzle

Guzzle is arguably the most popular HTTP client library for PHP, and fully supports PSR-7 since version 5. Let's install it:

$ composer require guzzlehttp/guzzle

We'll use the GuzzleHttp\Client to make our requests to feeds.

Creating a client

From here, we'll create our client. To do this, we'll create a class that:

• implements Zend\Feed\Reader\Http\ClientInterface
• accepts a GuzzleHttp\ClientInterface to its constructor
• uses the Guzzle client to make the request
• returns a zend-feed response decorating the actual PSR-7 response

The code looks like this:

use GuzzleHttp\Client;
use GuzzleHttp\ClientInterface as GuzzleClientInterface;
use Zend\Feed\Reader\Http\ClientInterface as FeedReaderHttpClientInterface;
use Zend\Feed\Reader\Http\Psr7ResponseDecorator;

class GuzzleClient implements FeedReaderHttpClientInterface
{
    /**
     * [@var](https://github.com/var) GuzzleClientInterface
     */
    private $client;

    /**
     * [@param](https://github.com/param) GuzzleClientInterface|null $client
     */
    public function __construct(GuzzleClientInterface $client = null)
    {
        $this->client = $client ?: new Client();
    }

    /**
     * {[@inheritdoc](https://github.com/inheritdoc)}
     */
    public function get($uri)
    {
        return new Psr7ResponseDecorator(
			$this->client->request('GET', $uri)
		);
    }
}

Using the client

In order to use our new client, we need to tell Zend\Feed\Reader\Reader about it:

Zend\Feed\Reader\Reader::setHttpClient(new GuzzleClient());

From this point forward, this custom client will be used to retrieve feeds.

References

This chapter is based on a blog post by Stefan Gehrig.