guzzle responseClass example

ItemCollection.php

<?php                                                                                                          
                                                                                                               
namespace Classmarkets\Api;                                                                          
                                                                                                               
use Guzzle\Service\Command\OperationCommand;                                                                   

class ItemCollection extends \Doctrine\Common\Collections\ArrayCollection                                      
{                         
    // This is the method Guzzle is looking for                                                                                     
    public static function fromCommand(OperationCommand $command)                                              
    {                                                                                                          
        $response = $command->getResponse();
        $data = $response->json(); // if you are not receiving json, there is a way of getting the raw response. Check the docs
                                                                              
        return self::fromArray($data);                                                                
    }                                                                                                          
                                                                                                               
    public static function fromArray(array $data)                                 
    {
        $collection = new self();

        // assign $collection's with values in $data

        return $collection
    }
}

service.yml

name: Item
operations:
    Search:
        httpMethod: GET
        uri: /search
        responseClass: Classmarkets\Api\ItemCollection