=== Redis Object Cache ===
Contributors: tillkruess
Donate link: https://www.paypal.me/tillkruss
Tags: redis, predis, phpredis, hhvm, pecl, caching, cache, object cache, performance, replication, clustering
Requires at least: 3.3
Tested up to: 5.3
Requires PHP: 5.4
Stable tag: 1.5.3
License: GPLv3
License URI: http://www.gnu.org/licenses/gpl-3.0.html

A persistent object cache backend powered by Redis. Supports Predis, PhpRedis, HHVM, replication, clustering and WP-CLI.


== Description ==

A persistent object cache backend powered by Redis. Supports [Predis](https://github.com/nrk/predis/), [PhpRedis (PECL)](https://github.com/phpredis/phpredis), [HHVM](https://github.com/facebook/hhvm/tree/master/hphp/system/php/redis), replication, clustering and [WP-CLI](http://wp-cli.org/).

To adjust the connection parameters, prefix cache keys or configure replication/clustering, please see [Other Notes](http://wordpress.org/extend/plugins/redis-cache/other_notes/).

Forked from Eric Mann's and Erick Hitter's [Redis Object Cache](https://github.com/ericmann/Redis-Object-Cache).

= Redis Cache Pro =

A **business class** Redis object cache backend. Truly reliable, highly optimized, fully customizable and with a dedicated engineer when you most need it.

* Rewritten for raw performance
* WordPress object cache API compliant
* Easy debugging & logging
* Fully unit tested (100% code coverage)
* Secure connections with TLS
* Seamless WP CLI & Debug Bar integration
* Optimized for WooCommerce, Jetpack & Yoast SEO

Learn more about [Redis Cache Pro](https://wprediscache.com/?utm_source=wp-plugin&utm_medium=readme).


== Installation ==

For detailed installation instructions, please read the [standard installation procedure for WordPress plugins](http://codex.wordpress.org/Managing_Plugins#Installing_Plugins).

1. Make sure [Redis is installed and running](http://redis.io/topics/quickstart).
2. Install and activate plugin.
3. Enable the object cache under _Settings -> Redis_, or in Multisite setups under _Network Admin -> Settings -> Redis_.
4. If necessary, adjust [connection parameters](http://wordpress.org/extend/plugins/redis-cache/other_notes/).

If your server doesn't support the [WordPress Filesystem API](https://codex.wordpress.org/Filesystem_API), you have to manually copy the `object-cache.php` file from the `/plugins/redis-cache/includes/` directory to the `/wp-content/` directory.


== Connection Parameters ==

By default the object cache drop-in will connect to Redis over TCP at `127.0.0.1:6379` and select database `0`.

To adjust the connection parameters, define any of the following constants in your `wp-config.php` file.

  * `WP_REDIS_CLIENT` (default: _not set_)

      Specifies the client used to communicate with Redis. Supports `hhvm`, `pecl` and `predis`.

  * `WP_REDIS_SCHEME` (default: `tcp`)

      Specifies the protocol used to communicate with an instance of Redis. Internally the client uses the connection class associated to the specified connection scheme. Supports `tcp` (TCP/IP), `unix` (UNIX domain sockets), `tls` (transport layer security) or `http` (HTTP protocol through Webdis).

  * `WP_REDIS_HOST` (default: `127.0.0.1`)

      IP or hostname of the target server. This is ignored when connecting to Redis using UNIX domain sockets.

  * `WP_REDIS_PORT` (default: `6379`)

      TCP/IP port of the target server. This is ignored when connecting to Redis using UNIX domain sockets.

  * `WP_REDIS_PATH` (default: _not set_)

      Path of the UNIX domain socket file used when connecting to Redis using UNIX domain sockets.

  * `WP_REDIS_DATABASE` (default: `0`)

      Accepts a numeric value that is used to automatically select a logical database with the `SELECT` command.

  * `WP_REDIS_PASSWORD` (default: _not set_)

      Accepts a value used to authenticate with a Redis server protected by password with the `AUTH` command.

  * `WP_REDIS_TIMEOUT` (default: `5`)

	  Amount of time in seconds (fractions of a second allowed) to attempt initial connection to Redis server before failing.

  * `WP_REDIS_READ_TIMEOUT` (default: `5`)

	  Amount of time in seconds (fractions of a second allowed) to attempt a read from the Redis server before failing.

  * `WP_REDIS_RETRY_INTERVAL` (default: _not set_)

	  Amount of time in milliseconds to retry a failed connection attempt.


== Configuration Parameters ==

To adjust the configuration, define any of the following constants in your `wp-config.php` file.

  * `WP_CACHE_KEY_SALT` (default: _not set_)

    Set the prefix for all cache keys. Useful in setups where multiple installs share a common `wp-config.php` or `$table_prefix` to guarantee uniqueness of cache keys.

  * `WP_REDIS_SELECTIVE_FLUSH` (default: _not set_)

    If set to `true`, flushing the cache will only delete keys that are prefixed with `WP_CACHE_KEY_SALT` (instead of emptying the entire Redis database). The selective flush is an atomic `O(n)` operation.

  * `WP_REDIS_MAXTTL` (default: _not set_)

    Set maximum time-to-live (in seconds) for cache keys with an expiration time of `0`.

  * `WP_REDIS_GLOBAL_GROUPS` (default: `['blog-details', 'blog-id-cache', 'blog-lookup', 'global-posts', 'networks', 'rss', 'sites', 'site-details', 'site-lookup', 'site-options', 'site-transient', 'users', 'useremail', 'userlogins', 'usermeta', 'user_meta', 'userslugs']`)

    Set the list of network-wide cache groups that should not be prefixed with the blog-id _(Multisite only)_.

  * `WP_REDIS_IGNORED_GROUPS` (default: `['counts', 'plugins']`)

    Set the cache groups that should not be cached in Redis.

  * `WP_REDIS_UNFLUSHABLE_GROUPS` (default: _not set_)

    Set groups not being flushed during a selective cache flush.

  * `WP_REDIS_DISABLED` (default: _not set_)

    Set to `true` to disable the object cache at runtime.

  * `WP_REDIS_GRACEFUL` (default: _not set_)

    Set to `false` to disable graceful failures and throw exceptions.

  * `WP_REDIS_SERIALIZER` (default: _not set_)

    Use PhpRedis’ built-in serializers. Supported values are `Redis::SERIALIZER_PHP` and `Redis::SERIALIZER_IGBINARY`.

  * `WP_REDIS_IGBINARY` (default: _not set_)

    Set to `true` to enable the [igbinary](https://github.com/igbinary/igbinary) serializer. Ignored when `WP_REDIS_SERIALIZER` is set.

  * `WP_REDIS_DISABLE_BANNERS` (default: _not set_)

    Set to `false` to disable promotions for [Redis Cache Pro](https://wprediscache.com/).

  * `WP_REDIS_DISABLE_METRICS` (default: _not set_)

    Set to `false` to disable the collection of system metrics. No user data such as emails, names, IPs, browser, usage or behavioral data is collected. Just version numbers and anonymous configuration options to help make better development decisions.


== Replication & Clustering ==

To use Replication, Sharding or Clustering, make sure your server is running PHP7 or higher (HHVM is not supported) and you consulted the [Predis](https://github.com/nrk/predis) or [PhpRedis](https://github.com/phpredis/phpredis) documentation.

For replication use the `WP_REDIS_SERVERS` constant, for sharding the `WP_REDIS_SHARDS` constant and for clustering the `WP_REDIS_CLUSTER` constant.

For authentication use the `WP_REDIS_PASSWORD` constant.

__Replication (Master-Slave):__

    define( 'WP_REDIS_SERVERS', [
        'tcp://127.0.0.1:6379?database=5&alias=master',
        'tcp://127.0.0.2:6379?database=5&alias=slave-01',
    ] );

__Replication (Redis Sentinel):__

    define( 'WP_REDIS_CLIENT', 'predis' );
    define( 'WP_REDIS_SENTINEL', 'mymaster' );
    define( 'WP_REDIS_SERVERS', [
        'tcp://127.0.0.1:5380',
        'tcp://127.0.0.2:5381',
        'tcp://127.0.0.3:5382',
    ] );

__Sharding:__

    define( 'WP_REDIS_SHARDS', [
        'tcp://127.0.0.1:6379?database=10&alias=shard-01',
        'tcp://127.0.0.2:6379?database=10&alias=shard-02',
        'tcp://127.0.0.3:6379?database=10&alias=shard-03',
    ] );

__Clustering (Redis 3.0+):__

    define( 'WP_REDIS_CLUSTER', [
        'tcp://127.0.0.1:6379?database=15&alias=node-01',
        'tcp://127.0.0.2:6379?database=15&alias=node-02',
    ] );


== WP-CLI Commands ==

To use the WP-CLI commands, make sure the plugin is activated:

    wp plugin activate redis-cache

The following commands are supported:

  * `wp redis status`

    Show the Redis object cache status and (when possible) client.

  * `wp redis enable`

    Enables the Redis object cache. Default behavior is to create the object cache drop-in, unless an unknown object cache drop-in is present.

  * `wp redis disable`

    Disables the Redis object cache. Default behavior is to delete the object cache drop-in, unless an unknown object cache drop-in is present.

  * `wp redis update-dropin`

    Updates the Redis object cache drop-in. Default behavior is to overwrite any existing object cache drop-in.


== Screenshots ==

1. Plugin settings, connected to a single Redis server.

2. Plugin settings, not connected to a Redis cluster.


== Changelog ==

= 1.5.3 =

- Fixed: Call to undefined function `get_plugin_data()`
- Fixed: Call to undefined method `WP_Object_Cache::redis_version()`

= 1.5.2 =

  * Added Redis version to diagnostics
  * Added `WP_REDIS_DISABLE_BANNERS` constant to disable promotions
  * Fixed an issue with `redis.replicate_commands()`

= 1.5.1 =

This plugin turned 5 years today (Nov 14th) and its only fitting to release the business edition today as well.
[Redis Cache Pro](https://wprediscache.com/) is a truly reliable, highly optimized and easy to debug rewrite of this plugin for SMBs.

  * Added execution times to actions
  * Added `WP_REDIS_VERSION` constant
  * Fixed PhpRedis v3 compatibility
  * Fixed an issue with selective flushing
  * Fixed an issue with `mb_*` functions not existing
  * Replaced Email Address Encoder card with Redis Cache Pro card
  * Gather version metrics for better decision making

= 1.5.0 =

Since Predis isn't maintained any longer, it's highly recommended to switch over to PhpRedis (the Redis PECL extention).

  * Improved Redis key name builder
  * Added support for PhpRedis serializers
  * Added `redis_object_cache_error` action
  * Added timeout, read-timeout and retry configuration
  * Added unflushable groups (defaults to `['userlogins']`)
  * Fixed passwords not showing in server list

= 1.4.3 =

  * Require PHP 5.4 or newer
  * Use pretty print in diagnostics
  * Throw exception if Redis library is missing
  * Fixed cache not flushing for some users
  * Fixed admin issues when `WP_REDIS_DISABLED` is `false`

= 1.4.2 =

  * Added graceful Redis failures and `WP_REDIS_GRACEFUL` constant
  * Improved cluster support
  * Added `redis_cache_expiration` filter
  * Renamed `redis_object_cache_get` filter to `redis_object_cache_get_value`

= 1.4.1 =

  * Fixed potential fatal error related to `wp_suspend_cache_addition()`

= 1.4.0 =

  * Added support for igbinary
  * Added support for `wp_suspend_cache_addition()`

= 1.3.9 =

  * Fixed `WP_REDIS_SHARDS` not showing up in server list
  * Fixed `WP_REDIS_SHARDS` not working when using PECL extension
  * Removed `WP_REDIS_SCHEME` and `WP_REDIS_PATH` leftovers

= 1.3.8 =

  * Switched from single file Predis version to full library

= 1.3.7 =

  * Revert back to single file Predis version

= 1.3.6 =

  * Added support for Redis Sentinel
  * Added support for sharing
  * Switched to PHAR version of Predis
  * Improved diagnostics
  * Added `WP_REDIS_SELECTIVE_FLUSH`
  * Added `$fail_gracefully` parameter to `WP_Object_Cache::__construct()`
  * Always enforce `WP_REDIS_MAXTTL`
  * Pass `$selective` and `$salt` to `redis_object_cache_flush` action
  * Don’t set `WP_CACHE_KEY_SALT` constant

= 1.3.5 =

  * Added basic diagnostics to admin interface
  * Added `WP_REDIS_DISABLED` constant to disable cache at runtime
  * Prevent "Invalid plugin header" error
  * Return integer from `increment()` and `decrement()` methods
  * Prevent object cache from being instantiated more than once
  * Always separate cache key `prefix` and `group` by semicolon
  * Improved performance of `build_key()`
  * Only apply `redis_object_cache_get` filter if callbacks have been registered
  * Fixed `add_or_replace()` to only set cache key if it doesn't exist
  * Added `redis_object_cache_flush` action
  * Added `redis_object_cache_enable` action
  * Added `redis_object_cache_disable` action
  * Added `redis_object_cache_update_dropin` action

= 1.3.4 =

  * Added WP-CLI support
  * Show host and port unless scheme is unix
  * Updated default global and ignored groups
  * Do a cache flush when activating, deactivating and uninstalling

= 1.3.3 =

  * Updated Predis to `v1.1.1`
  * Added `redis_instance()` method
  * Added `incr()` method alias for Batcache compatibility
  * Added `WP_REDIS_GLOBAL_GROUPS` and `WP_REDIS_IGNORED_GROUPS` constant
  * Added `redis_object_cache_delete` action
  * Use `WP_PLUGIN_DIR` with `WP_CONTENT_DIR` as fallback
  * Set password when using a cluster or replication
  * Show Redis client in `stats()`
  * Change visibility of `$cache` to public
  * Use old array syntax, just in case

= 1.3.2 =

  * Make sure `$result` is not `false` in `WP_Object_Cache::get()`

= 1.3.1 =

  * Fixed connection issue

= 1.3 =

  * New admin interface
  * Added support for `wp_cache_get()`'s `$force` and `$found` parameter
  * Added support for clustering and replication with Predis

= 1.2.3 =

  * UI improvements

= 1.2.2 =

  * Added `redis_object_cache_set` action
  * Added `redis_object_cache_get` action and filter
  * Prevented duplicated admin status messages
  * Load bundled Predis library only if necessary
  * Load bundled Predis library using `WP_CONTENT_DIR` constant
  * Updated `stats()` method output to be uniform with WordPress

= 1.2.1 =

  * Added `composer.json`
  * Added deactivation and uninstall hooks to delete `object-cache.php`
  * Added local serialization functions for better `advanced-cache.php` support
  * Updated bundled Predis version to `1.0.3`
  * Updated heading structure to be semantic

= 1.2 =

  * Added Multisite support
  * Moved admin menu under _Settings_ menu
  * Fixed PHP notice in `get_redis_client_name()`

= 1.1.1 =

  * Call `select()` and optionally `auth()` if HHVM extension is used

= 1.1 =

  * Added support for HHVM's Redis extension
  * Added support for PECL Redis extension
  * Added `WP_REDIS_CLIENT` constant, to set preferred Redis client
  * Added `WP_REDIS_MAXTTL` constant, to force expiration of cache keys
  * Improved `add_or_replace()`, `get()`, `set()` and `delete()` methods
  * Improved admin screen styles
  * Removed all internationalization/localization from drop-in

= 1.0.2 =

  * Added "Flush Cache" button
  * Added support for UNIX domain sockets
  * Improved cache object retrieval performance significantly
  * Updated bundled Predis library to version `1.0.1`

= 1.0.1 =

  * Load plugin translations
  * Hide global admin notices from non-admin users
  * Prevent direct file access to `redis-cache.php` and `admin-page.php`
  * Colorize "Disable Object Cache" button
  * Call `Predis\Client->connect()` to avoid potential uncaught `Predis\Connection\ConnectionException`

= 1.0 =

  * Initial release


== Upgrade Notice ==

= 1.4.2 =

This update renames the `redis_object_cache_get` filter to avoid conflicts. Update your code if necessary.

= 1.4.0 =

This update adds support for igbinary and `wp_suspend_cache_addition()`.

= 1.3.9 =

This update contains fixes for sharding.

= 1.3.8 =

This update contains a critical fix for Predis.

= 1.3.7 =

This update fixes an issue with Predis in some environments.

= 1.3.6 =

This update contains various improvements.

= 1.3.5 =

This update contains various changes, including performance improvements and better Batcache compatibility.

= 1.3.4 =

This update contains several improvements, including WP CLI and WordPress 4.6 support.

= 1.3.3 =

This update contains several improvements.

= 1.3.2 =

This update includes a critical fix for PhpRedis.

= 1.3.1 =

This update includes a critical connection issue fix.

= 1.3 =

This update includes a new admin interface and support for clustering and replication with Predis.

= 1.2.3 =

This updated includes several UI improvements.

= 1.2.2 =

This updated includes several bug fixes and improvements.

= 1.2.1 =

This update includes several improvements and compatibility fixes.

= 1.1.1 =

This update fixes critical bugs with the HHVM extension

= 1.1 =

This update includes bug fixes and adds supports for HHVM/PECL Redis extensions.

= 1.0.2 =

This update includes significant speed improvements and support for UNIX domain sockets.

= 1.0.1 =

This update includes several security, user interface and general code improvements.