ZF Http Cache

Introduction

zf-http-cache is a ZF2 module for automating http-cache tasks within a Zend Framework 2 application.

Installation

Run the following composer command:

$ composer require "zfcampus/zf-http-cache:^1.0"

Alternately, manually add the following to your composer.json, in the require section:

"require": {
    "zfcampus/zf-http-cache": "^1.0"
}

And then run composer update to ensure the module is installed.

Finally, add the module name to your project's config/application.config.php under the modules key:

return [
    /* ... */
    'modules' => [
        /* ... */
        'ZF\HttpCache',
    ],
    /* ... */
];

Configuration

User Configuration

As a rule of thumb, avoid as much as possible using anonymous functions since it prevents you from caching your configuration.

The top-level configuration key for user configuration of this module is zf-http-cache.

The config/module.config.php file contains a self-explanative example of configuration.

Key: controllers

The controllers key is utilized for mapping any of

  • a route name
  • a concatenated controller::action
  • a controller
  • a regexp
  • a wildcard

Each is case sensitive, and will map one or more HTTP methods to the cache header configuration specific to the given rule.

Example:

// See the `config/application.config.php` for a complete commented example
'zf-http-cache' => [
    /* ... */
    'controllers' => [
        '<controller>' => [
            '<http-method>'  => [
                '<cache-header-name>' => [
                    'override' => true,
                    'value'    => '<cache-header-value>',
                ],
            ],
        ],
    ],
    /* ... */
],    
Key: <controller>

Either

  • a concatenation of $controller::$action
  • a controller name (as returned by Zend\Mvc\MvcEvent::getRouteMatch()->getParam('controller'); the value is case-sensitive)
  • a regexp (see <regex_delimiter> key)
  • a wildcard

A wildcard matches any unspecified controllers.

Key: <http-method>

Either a lower cased HTTP method (get, post, etc.) (as returned by Zend\Http\Request::getMethod()) or a wildcard.

A wildcard stands for all the non-specified HTTP methods.

Key: <cache-header-name>

An HTTP cache header name (Cache-control, expires, etag etc.).

ETags

For ETags you can specify a custom generator in the configuration:

'etag' => [
    'override' => true,
    'generator' => 'Your\Own\ETagGenerator',
],

A generator example can be found in \ZF\HttpCache\DefaultETagGenerator.

Key: <cache-header-value>

The value for the cache header.

Key: override

Whether to override the cache headers possibly sent by your application.

Key: enable

The enable key is utilized for enabling/disabling the http cache module at run time.

If you no longer need this module, rather consider removing the module from the application.config.php list.

Caution: when disabled, http cache module doesn't override/remove the cache headers sent by your application.

Example:

'zf-http-cache' => [
    /* ... */
    'enable' => true, // Cache module is enabled.
    /* ... */
],

Key: http_codes_black_list

The http_codes_black_list is utilized to avoid caching the responses with the listed HTTP status codes. Defaults to all others than 200.

Example:

'zf-http-cache' => [
    /* ... */
    'http_codes_black_list' => ['201', '304', '400', '500'], // Whatever the other configurations, the responses with these HTTP codes won't be cached.
    /* ... */
],

Key: regex_delimiter

This key is used to enable the evaluation of the key as a regular expression.

It must contain the delimiter of the regular expression.

If you don't want to use regular expression in your configuration set this to null to avoid inutil parsing.

Regular expressions are tested in the very order they appear in the configuration, first matching wins.

Regexp wins over wildcard.

Caution: When this value is not empty and no litteral key corresponds to the current controller, a preg_match is used.

Example:

'zf-http-cache' => [
    /* ... */
    'regex_delimiter' => '~',
    /* ... */
    'controllers' => [
        '~.*~' => [ // Acts as a wildcard.
            /* ... */
        ],
    ],
    /* ... */
],

System Configuration

The following configuration is provided in config/module.config.php:

'service_manager' => [
    'factories' => [
        'ZF\HttpCache\HttpCacheListener' => 'ZF\HttpCache\HttpCacheListenerFactory',
    ],
],

ZF2 Events

Listeners

ZF\HttpCache\HttpCacheListener

This listener is attached to the MvcEvent::EVENT_ROUTE and MvcEvent::EVENT_FINISH events with the low priority of -10000.