[php] Guzzle 6: no more json() method for responses

If you guys still interested, here is my workaround based on Guzzle middleware feature:

1. Create JsonAwaraResponse that will decode JSON response by Content-Type HTTP header, if not - it will act as standard Guzzle Response:

   <?php
   
   namespace GuzzleHttp\Psr7;
   
   
   class JsonAwareResponse extends Response
   {
       /**
        * Cache for performance
        * @var array
        */
       private $json;
   
       public function getBody()
       {
           if ($this->json) {
               return $this->json;
           }
           // get parent Body stream
           $body = parent::getBody();
   
           // if JSON HTTP header detected - then decode
           if (false !== strpos($this->getHeaderLine('Content-Type'), 'application/json')) {
               return $this->json = \json_decode($body, true);
           }
           return $body;
       }
   }
   

2. Create Middleware which going to replace Guzzle PSR-7 responses with above Response implementation:

   <?php
   
   $client = new \GuzzleHttp\Client();
   
   /** @var HandlerStack $handler */
   $handler = $client->getConfig('handler');
   $handler->push(\GuzzleHttp\Middleware::mapResponse(function (\Psr\Http\Message\ResponseInterface $response) {
       return new \GuzzleHttp\Psr7\JsonAwareResponse(
           $response->getStatusCode(),
           $response->getHeaders(),
           $response->getBody(),
           $response->getProtocolVersion(),
           $response->getReasonPhrase()
       );
   }), 'json_decode_middleware');
   

After this to retrieve JSON as PHP native array use Guzzle as always:

$jsonArray = $client->get('http://httpbin.org/headers')->getBody();

Tested with guzzlehttp/guzzle 6.3.3