Guzzle Cache Subscriber

Provides a private transparent proxy cache for caching HTTP responses.

Here's a simple example of how it's used:

use GuzzleHttp\Client;
use GuzzleHttp\Subscriber\Cache\CacheSubscriber;

$client = new Client(['defaults' => ['debug' => true]]);

// Use the helper method to attach a cache to the client.
CacheSubscriber::attach($client);

// Send the first request
$a = $client->get('http://en.wikipedia.org/wiki/Main_Page');

// Send the second request. This will find a cache hit which must be
// validated. The validation request returns a 304, which yields the original
// cached response.
$b = $client->get('http://en.wikipedia.org/wiki/Main_Page');

Running the above code sample should output verbose cURL information that looks something like this:

> GET /wiki/Main_Page HTTP/1.1
Host: en.wikipedia.org
User-Agent: Guzzle/4.2.1 curl/7.37.0 PHP/5.5.13
Via: 1.1 GuzzleCache/4.2.1

< HTTP/1.1 200 OK
< Server: Apache
< X-Content-Type-Options: nosniff
< Content-language: en
< X-UA-Compatible: IE=Edge
< Vary: Accept-Encoding,Cookie
< Last-Modified: Thu, 21 Aug 2014 01:51:49 GMT
< Content-Type: text/html; charset=UTF-8
< X-Varnish: 2345493325, 1998949714 1994269567
< Via: 1.1 varnish, 1.1 varnish
< Transfer-Encoding: chunked
< Date: Thu, 21 Aug 2014 02:34:12 GMT
< Age: 2541
< Connection: keep-alive
< X-Cache: cp1055 hit (1), cp1068 frontend hit (25353)
< Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
< Set-Cookie: GeoIP=US:Seattle:47.6062:-122.3321:v4; Path=/; Domain=.wikipedia.org
<
* Connection #0 to host en.wikipedia.org left intact
* Re-using existing connection! (#0) with host en.wikipedia.org
> GET /wiki/Main_Page HTTP/1.1
Host: en.wikipedia.org
User-Agent: Guzzle/4.2.1 curl/7.37.0 PHP/5.5.13
Via: 1.1 GuzzleCache/4.2.1, 1.1 GuzzleCache/4.2.1
If-Modified-Since: Thu, 21 Aug 2014 01:51:49 GMT

< HTTP/1.1 304 Not Modified
< Server: Apache
< X-Content-Type-Options: nosniff
< Content-language: en
< X-UA-Compatible: IE=Edge
< Vary: Accept-Encoding,Cookie
< Last-Modified: Thu, 21 Aug 2014 01:51:49 GMT
< Content-Type: text/html; charset=UTF-8
< X-Varnish: 2345493325, 1998950450 1994269567
< Via: 1.1 varnish, 1.1 varnish
< Date: Thu, 21 Aug 2014 02:34:12 GMT
< Age: 2541
< Connection: keep-alive
< X-Cache: cp1055 hit (1), cp1068 frontend hit (25360)
< Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
< Set-Cookie: GeoIP=US:Seattle:47.6062:-122.3321:v4; Path=/; Domain=.wikipedia.org
<
* Connection #0 to host en.wikipedia.org left intact

Installing

Add the following to your composer.json:

{
    "require": {
        "guzzlehttp/cache-subscriber": "0.1.*@dev"
    }
}

Creating a CacheSubscriber

The easiest way to create a CacheSubscriber is using the attach() helper method of GuzzleHttp\Subscriber\Cache\CacheSubscriber. This method accepts a request or client object and attaches the necessary subscribers used to perform cache lookups, validation requests, and automatic purging of resources.

The attach() method accepts the following options:

storage

A GuzzleHttp\Subscriber\Cache\CacheStorageInterface object used to store cached responses. If no value is not provided, an in-memory array cache will be used.

validate

A Boolean value that determines if cached response are ever validated against the origin server. This setting defaults to true but can be disabled by passing false.

purge

A Boolean value that determines if cached responses are purged when non-idempotent requests are sent to their URI. This setting defaults to true but can be disabled by passing false.

can_cache

An optional callable used to determine if a request can be cached. The callable accepts a GuzzleHttp\Message\RequestInterface and returns a Boolean value. If no value is provided, the default behavior is utilized.

Warning

This is a WIP update for Guzzle 4+. It hasn't been tested and is in active development. Expect bugs and breaks.