inception/redis-cache/readme.txt

=== Redis Object Cache ===
Contributors: tillkruess, a5hleyrich
Donate link: https://github.com/sponsors/tillkruss
Tags: redis, object cache, cache, object caching, caching performance, relay, predis, phpredis
Requires at least: 3.3
Tested up to: 6.3
Requires PHP: 7.2
Stable tag: 2.4.4
License: GPLv3
License URI: https://www.gnu.org/licenses/gpl-3.0.html

A persistent object cache backend powered by Redis®¹. Supports Predis, PhpRedis, Relay, replication, sentinels, clustering and WP-CLI.


== Description ==

A persistent object cache backend powered by Redis®¹. Supports [Predis](https://github.com/predis/predis/), [PhpRedis (PECL)](https://github.com/phpredis/phpredis), [Relay](https://relaycache.com), replication, sentinels, clustering and [WP-CLI](https://wp-cli.org/).

To adjust the connection parameters, prefix cache keys or configure replication/clustering, see the [configuration options](https://github.com/rhubarbgroup/redis-cache/#configuration).

= Object Cache Pro =

A **business class** Redis®¹ object cache backend. Truly reliable, highly optimized, fully customizable and with a dedicated engineer when you most need it.

* Rewritten for raw performance
* 100% WordPress API compliant
* Faster serialization and compression
* Easy debugging & logging
* Cache prefetching and analytics
* Fully unit tested (100% code coverage)
* Secure connections with TLS
* Health checks via WordPress & WP CLI
* Optimized for WooCommerce, Jetpack & Yoast SEO

Learn more about [Object Cache Pro](https://objectcache.pro/?ref=oss&utm_source=wp-plugin&utm_medium=readme).

¹ Redis is a registered trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by Redis Object Cache is for referential purposes only and does not indicate any sponsorship, endorsement or affiliation between Redis and Redis Object Cache.

== Installation ==

For detailed installation instructions, please read the extensive [installation instructions](https://github.com/rhubarbgroup/redis-cache/blob/develop/INSTALL.md).

== Troubleshooting ==

Answers to common questions and troubleshooting of common errors can be found in the [FAQ](https://github.com/rhubarbgroup/redis-cache/blob/develop/FAQ.md). Reading these is always faster than waiting for a response in the support forums.

== Configuration ==

The plugin comes with vast set of [configuration options](https://github.com/rhubarbgroup/redis-cache/#configuration) and [connection examples](https://github.com/rhubarbgroup/redis-cache/#connections). Advanced users may consult [Scaling and replication](https://github.com/rhubarbgroup/redis-cache/blob/develop/README.md#scaling)

== WP CLI commands ==

Redis Object Cache has various WP CLI commands, for more information run `wp help redis` after installing the plugin.

== Screenshots ==

1. Plugin settings, connected to a single Redis server.
2. Plugin settings, displaying recent response time metrics.
3. Plugin settings, showing diagnostic information.
4. Dashboard widget, displaying recent response time metrics.


== Changelog ==

= 2.4.4 =

- Improved handling of unexpected transaction results

= 2.4.3 =

- Fixed PHP `<=7.2` syntax error
- Fixed loading error-page translations

= 2.4.2 =

- Made admin-bar script more robust
- Improved recovery instructions on `redis-error.php`
- Improved CloudLinux detection
- Localization improvements
- Prevent W3 Total Cache and LiteSpeed Cache from overwriting drop-in
- Fixed ACL username support when using Predis and array syntax

= 2.4.1 =

- Fix PHP `<=7.2` syntax error

= 2.4.0 =

- Flush cache when toggling the object cache
- Show a custom error message when Redis is unreachable
- Don't allow object cache to be enabled when Redis is unreachable
- Deprecated risky `WP_REDIS_SERIALIZER` configuration constant, use `WP_REDIS_IGBINARY` instead
- Support `WP_REDIS_USERNAME` when using Predis
- Show cache hit ratio decimal points in Admin Bar node
- Obscure secrets when displaying `WP_REDIS_SERVERS`
- Improved CloudLinux's Accelerate WP compatibility
- Admin bar cache flush now uses AJAX

= 2.3.0 =

- Show dashboard widget only to admins
- Added Admin Bar node (disable using `WP_REDIS_DISABLE_ADMINBAR`)
- Added `WP_REDIS_SSL_CONTEXT` configuration constant
- Throw errors when connection error occurs
- Added support for usernames when using Predis
- Added support for loading Predis from `WP_REDIS_PLUGIN_PATH`
- Made Predis unix socket connections stricter
- Fixed rare group flushing bug
- Fixed cluster ping when using Predis
- Updated Predis to v2.1.2
- Improved documentation

= 2.2.4 =

- Register `wp redis` CLI command late
- Don't compete with Object Cache Pro for `wp redis` command
- Prevent Perflab from overwriting the object cache drop-in
- Updated Predis to v2.1.1
- Avoid type error when transaction fails
- Check for incompatible content type headers

= 2.2.3 =

- Added `wp_cache_flush_group()` support
- Updated Credis to v1.14.0
- Drop `$delay` parameter from `wp_cache_flush()`
- Prevent rare error in diagnostics when reading connection errors

= 2.2.2 =

- Use `QM_Data_Cache` instead of `QM_Data`
- Fixed `WP_Error` use statement non-compound name warning

= 2.2.1 =

- Added WordPress 6.1 `wp_cache_supports()` function
- Updated Predis to v2.0.3
- Avoid early `microtime()` calls in `WP_Object_Cache::get()`
- Support Query Monitor's new `QM_Data` class
- Throw exception of pipeline returns unexpected results

= 2.2.0 =

- Added `redis_cache_add_non_persistent_groups` filter
- Fixed `wp_add_dashboard_widget` parameters
- Fixed `WP_REDIS_SERVERS` replication issue with Predis v2.0
- Fixed `WP_REDIS_CLUSTER` string support
- Fixed issue when `MGET` fails in `get_multiple()` call
- Fixed several warnings in the event of pipeline failures

= 2.1.6 =

- Fixed SVN discrepancies

= 2.1.5 =

- Fixed `is_predis()` call

= 2.1.4 =

- Added `is_predis()` helper

= 2.1.3 =

- Fixed bug in `wp_cache_add_multiple()` and `wp_cache_set_multiple()`

= 2.1.2 =

- Fixed and improved `wp_cache_*_multiple()` logic
- Call `redis_object_cache_set` action in `wp_cache_set_multiple()`
- Call `redis_object_cache_delete` action in `wp_cache_delete_multiple()`
- Check if raw group name is ignored, not sanitized name
- Removed tracing

= 2.1.1 =

- Bumped PHP requirement to 7.2
- Renamed `WP_REDIS_DIR` to `WP_REDIS_PLUGIN_DIR`
- Fixed rare fatal error in diagnostics
- Allow Predis v1.1 Composer installs
- Support using `WP_REDIS_CLUSTER` string

= 2.1.0 =

- Bumped PHP requirement to 7.0
- Deprecated Credis and HHVM clients
- Updated Predis to v2.0.0
- Updated Credis to v1.13.1
- Improved cluster readability in diagnostics
- Improved connecting to clusters
- Fixed pinging clusters after connecting
- Fixed several bugs in `connect_using_credis()`

= 2.0.26 =

- Fixed a bug in `wp_cache_delete_multiple()` when using Predis
- Fixed a bug in `wp_cache_add_multiple()` when cache addition is suspended

= 2.0.25 =

- Removed broken `wp_cache_add_multiple()` function

= 2.0.24 =

- Improve metrics label/tooltip formatting
- Fix metrics chart not rendering
- Updated Predis to v1.1.10
- Updated Credis to v1.13.0
- Support `composer/installers` v1 and v2
- Link to settings page when foreign drop-in was found
- Added `wp_cache_flush_runtime()` function
- Added `wp_cache_add_multiple()` function
- Added `wp_cache_delete_multiple()` function

= 2.0.23 =

- Added support for [Relay](https://relaycache.com)
- Minor UX fixes and improvements
- Fixed PHP 8.1 deprecation notice
- Updated ApexCharts to v3.31.0

= 2.0.22 =

- PHP 8.1 compatibility fixes
- Upgraded to Predis v1.1.9
- Added settings link to widget
- Overhauled diagnostics pane
- Updated ApexCharts to v3.30.0
- Redirect to plugin settings after activation
- Fixed wrong path to `diagnostics.php` file
- Fixed chart overflow in settings tab
- Fixed Predis cluster ping
- Avoid warning when content folder is not writeable

= 2.0.21 =

- Added metrics diagnostics
- Added `WP_Object_Cache::decr()` alias
- Moved `diagnostics.php` file

= 2.0.20 =

- Fix wp.org release

= 2.0.19 =

- Make metric identifier unique
- Set unique prefix for sites hosted on Cloudways
- Don't print HTML debug comment when `WP_CLI` is `true`

= 2.0.18 =

- Added `redis_object_cache_trace` action and `WP_REDIS_TRACE` constant
- Updated ApexCharts to v3.26.0
- Fixed and issue with `WP_REDIS_DISABLE_METRICS`

= 2.0.17 =

- Code cleanup
- Fixed missing metrics
- Fixed filesystem test

= 2.0.16 =

- Updated Credis to v1.11.4
- Fixed drop-in notice styling
- Moved metrics into dedicated class
- Added `redis_cache_validate_dropin` filter
- Use `WP_DEBUG_DISPLAY` (instead of `WP_DEBUG`) constant to display debug information
- Fixed rare error in `wp_cache_get_multiple()`
- Removed `intval()` usage

= 2.0.15 =

- Reverted `build_key()` changes due to issues in multisite environments

= 2.0.14 =

- Made Object Cache Pro card translatable
- Added `WP_REDIS_SERIALIZER` to diagnostics
- Improved speed of `build_key()`
- Support settings `WP_REDIS_PREFIX` and `WP_REDIS_SELECTIVE_FLUSH` via environment variable
- Added `WP_REDIS_METRICS_MAX_TIME` to adjust stored metrics timeframe
- Delay loading of text domain and schedule until `init` hook
- Upgraded bundled Predis library to v1.1.6
- Prevent variable referencing issue in `connect_using_credis()`

= 2.0.13 =

- Updated bundled Predis library to v1.1.4
- Made `redis-cache` a global group for improved metrics on multisite
- Switched to short array syntax
- Added `@since` tags to all hooks
- Use `parse_url()` instead of `wp_parse_url()` in drop-in
- Fixed plugin instance variable name in `wp redis status`

= 2.0.12 =

- Fixed bytes metrics calculation
- Fixed an issue with non-standard Predis configurations
- Improve WordPress Coding Standards

= 2.0.11 =

- Fixed an issue in `wp_cache_get_multiple()` when using Predis
- Prevent undefined index notice in diagnostics

= 2.0.10 =

- Fixed unserializing values in `wp_cache_get_multiple()`

= 2.0.9 =

- Highlight current metric type using color
- Show "Metrics" tab when metrics are disabled
- Refactored connection and Redis status logic
- Updated Predis to v1.1.2
- Remove Predis deprecation notice
- Fixed fetching derived keys in `wp_cache_get_multiple()`

= 2.0.8 =

- Fixed tabs not working in 2.0.6 and 2.0.7 due to WP.org SVN issue

= 2.0.7 =

- Fixed issue with `wp_cache_get_multiple()`

= 2.0.6 =

- Added experimental filesystem test to diagnostics
- Refactored settings tab logic (fixed jumping, too)
- Fixed issues with `wp_cache_get_multiple()`
- Return boolean from `wp_cache_delete()`
- Use `redis-cache` as JS event namespace
- Hide Pro line in widget when banners are disabled
- Renamed `redis_object_cache_get_multi` action to `redis_object_cache_get_multiple`

= 2.0.5 =

Version 2.0 is a significant rewrite of the plugin. Please read the v2.0.0 release notes.

- Fixed multisite action buttons not working
- Removed outdated PHP 5.4 warning
- Added `read_timeout` support to Credis
- Display connection parameters when using Credis
- Added wiki link to Predis upgrade notice

= 2.0.4 =

- Attempt to reliably update the dropin when it's outdated
- Show ACL username on settings screen
- Show full diagnostics with `wp redis status`
- Always set `FS_CHMOD_FILE` when copying the `object-cache.php`
- Don't encode bullets in password diagnostics
- Call `redis_object_cache_update_dropin` during dropin update

= 2.0.3 =

- Hide "Metrics" tab when metrics are disabled
- Fixed `admin.js` not loading in multisite environments
- Avoid fatal error when interacting with metrics but Redis went away
- Added `WP_Object_Cache::__get()` for backwards compatibility

= 2.0.2 =

- Updated POT file and comments for translators

= 2.0.1 =

- Support older versions of Query Monitor
- Made "Dropin" status more helpful
- Hide Redis version in settings when it isn't available
- Collapsed dependency paths using `composer-custom-directory-installer` package
- Prevent `QM_Collector` conflicts with other plugins
- Prevent metric issues when cache is not available
- Fixed "Settings" link in plugin list
- Fixed `WP_REDIS_DISABLED` logic

= 2.0.0 =

Version 2.0 is a significant rewrite. The plugin now requires PHP 5.6, just like WordPress 5.2 does.

The GitHub and Composer repository was moved from `tillkruss/redis-cache` to `rhubarbgroup/redis-cache`.

On multisite networks, be sure to "Network Activate" the plugin after upgrading to v2.x.

- Require PHP 5.6
- Plugin is now "network-only"
- Switch to WPCS for code standards
- Overhauled the settings screen
- Added object cache metrics (on dashboard widget and settings)
- Added support for Query Monitor
- Added `Rhubarb\RedisCache` namespace to all files
- Added support for WP 5.5's new `wp_cache_get_multi()` function
- Added `redis_object_cache()` function to retrieve plugin instance
- Added dropin warnings to network dashboard
- Added support for setting Sentinel database numbers
- Support Redis 6 ACL username and password authentication
- Support overwriting existing dropin on setting screen
- Use singleton pattern to instantiate plugin
- Use Composer to install and load Predis
- Update object cache dropin during plugin update
- Use separate methods to connect with all clients
- Removed `CUSTOM_USER_TABLE` and `CUSTOM_USER_META_TABLE` weirdness
- Added `themes` as ignored group
- Changed default connection and read timeout to 1 second
- Prevent race condition in `add_or_replace()`
- Renamed `WP_CACHE_KEY_SALT` to `WP_REDIS_PREFIX` for clarity
- Replaced "slave" terminology with "replica"
- Only `SELECT` database when it's not `0`

= 1.6.1 =

- Fixed issue with footer comment showing during AJAX requests

= 1.6.0 =

- Improved group name sanitization (thanks @naxvog)
- Prevent fatal error when replacing foreign dropin
- Added HTML footer comment with optional debug information
- Removed prefix suggestions

_The HTML footer comment only prints debug information when `WP_DEBUG` is enabled. To disable the comment entirely, set the `WP_REDIS_DISABLE_COMMENT` constant to `true`._

= 1.5.9 =

- Fixed missing `$info` variable assignment in constructor
- Fixed MaxTTL warning condition
- Switched to using default button styles

= 1.5.8 =

- Added warning message about invalid MaxTTL
- Added warning about unmaintained Predis library
- Added suggestion about shorter, human-readable prefixes
- Added Redis Cache Pro compatibility to settings
- Fixed flushing the cache when the prefix contains special characters
- Fixed calling Redis `INFO` when using clusters
- Cleaned up the settings a little bit

= 1.5.7 =

- Added support for PhpRedis TLS connections
- Added support for timeout, read timeout and password when using PhpRedis cluster
- Fixed issue with `INFO` command
- Fixed object cloning when setting cache keys

= 1.5.6 =

- Added object cloning to in-memory cache
- Fixed PHP notice related to `read_timeout` parameter

= 1.5.5 =

Please flush the object cache after updating the drop to v1.5.5 to avoid dead keys filling up Redis memory.

- Removed lowercasing keys
- Remove scheduled metrics event
- Fixed Redis version call when using replication

= 1.5.4 =

- Removed metrics

= 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.
[Object Cache Pro](https://objectcache.pro/) 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 extension).

- 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 ==

= 2.4.0 =

Version 2.4.0 includes several stability and QoL improvements.