Guzzle cache that actually works..

guzzle-cache-plugin.php

<?php
/**
 * Caching to filesystem using ZendCache
 * Cache as much as possible, very convenient for dev (default ttl = 3600)
 */

use Guzzle\Http\Client;
use Guzzle\Plugin\Cache\CachePlugin; 
use Guzzle\Plugin\Cache\SkipRevalidation;
use Guzzle\Plugin\Cache\DefaultCacheStorage;
use Guzzle\Cache\CacheAdapterFactory;
use Zend\Cache\Storage\Adapter\Filesystem as FilesystemCache;

$client = new Client('http://api.example.com');

$storage = new FilesystemCache(['cacheDir' => 'some_path']);

$cachePlugin = new CachePlugin([
    'storage' => new DefaultCacheStorage(CacheAdapterFactory::fromCache($storage)),
    'revalidation' => new SkipRevalidation,
]);

$client->addSubscriber($cachePlugin);