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=== ZenCache ===

Stable tag: 160316
Requires at least: 4.1
Tested up to: 4.5-alpha
Text Domain: zencache

License: GPLv2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html

Contributors: WebSharks, JasWSInc, raamdev
Donate link: http://websharks-inc.com/r/wp-theme-plugin-donation/
Tags: cache, speed, performance, fast, caching, advanced cache, static, client-side cache, rss cache, feed cache, gzip compression, page cache

ZenCache is an advanced WordPress caching plugin inspired by simplicity. Speed up your site (BIG time!) with a reliable and fast WordPress cache.

== Description ==

**ANNOUNCEMENT: [ZenCache is now Comet Cache!](https://cometcache.com/r/announcing-comet-cache-formerly-zencache/)**

**To receive plugin updates and bug fixes, please install [Comet Cache](https://wordpress.org/plugins/comet-cache/) instead.**

================================================================

If you care about the speed of your site, ZenCache is one of those plugins that you absolutely MUST have installed :-) ZenCache takes a real-time snapshot (building a cache) of every Page, Post, Category, Link, etc. These snapshots are then stored (cached) intuitively, so they can be referenced later, in order to save all of that processing time that has been dragging your site down and costing you money.

The ZenCache plugin uses configuration options that you select from the options panel. See: **ZenCache -› Options** in your Dashboard. Once a file has been cached, ZenCache uses advanced techniques that allow it to recognize when it should and should not serve a cached version of the file. By default, ZenCache does not serve cached pages to users who are logged in, or to users who have left comments recently. ZenCache also excludes administrative pages, login pages, POST/PUT/DELETE/GET(w/ query string) requests and/or CLI processes.

= Features =

- SIMPLE and well-documented configuration (just enable and you're all set!).
- Options to control the automatic cache clearing behavior for Home and Posts Page, Author Page, Category, Tag, and Custom Term Archives, Custom Post Type Archives, RSS/RDF/ATOM Feeds, and XML Sitemaps.
- URI exclusion patterns (now supporting wildcards too).
- User-Agent exclusion patterns (now supporting wildcards too).
- HTTP referrer exclusion patterns (now supporting wildcards too).
- The ability to set an automatic expiration time for cache files.
- Client-Side Caching (to allow double-caching in the client-side browser).
- Caching for 404 requests to reduce the impact of those requests on the server.
- RSS, RDF, and Atom Feed caching.
- The ability to cache or ignore URLs that contain query strings (GET Requests).
- An Advanced Cache Plugin system for theme and plugin developers.

= Pro Features =

- The ability to cache logged-in users too! (VERY powerful, particularly for membership sites).
- A new improved "Clear Cache" button in the admin bar (along with an option to enable/disable this feature).
- The ability to disable Dashboard notifications related to automatic clearing/purging on change detections.
- The ability to clear Markdown-related cache files generated by the s2Clean theme for WordPress (if installed).
- The ability to run custom PHP code whenever the cache is cleared.
- Cache Statistics to help you gain insight into the status of your site cache.
- Import/Export functionality for ZenCache configuration files.
- A Dynamic Version Salt (customize the caching engine).
- HTML Compressor to automatically combine and compresses CSS/JS/HTML code.
- Auto-Cache Engine to pre-cache your site at 15-minute intervals.
- Static CDN Filters to serve some and/or ALL static files on your site from a CDN of your choosing, including support for Multiple CDN Host Names, Domain Sharding, and WordPress Multisite Networks.
- An Automatic Updater to update ZenCache Pro from your WordPress Dashboard.
- Rockstar support for all ZenCache features.

TIP: you can preview Pro features in the free version by clicking the "Preview Pro Features" link at the top of your ZenCache options.

== Screenshots ==

1. ZenCache Screenshot #1
2. ZenCache Screenshot #2
3. ZenCache Screenshot #3
4. ZenCache Screenshot #4
5. ZenCache Screenshot #5
6. ZenCache Screenshot #6
7. ZenCache Screenshot #7
8. ZenCache Screenshot #8
9. ZenCache Screenshot #9
10. ZenCache Screenshot #10

== Installation ==

**Quick Tip:** WordPress® can only deal with one cache plugin being activated at a time. Please uninstall any existing cache plugins that you've tried in the past. In other words, if you've installed W3 Total Cache, WP Super Cache, DB Cache Reloaded, or any other caching plugin, uninstall them all before installing ZenCache. One way to check, is to make sure this file: `wp-content/advanced-cache.php` and/or `wp-content/object-cache.php` are NOT present; and if they are, delete these files BEFORE installing ZenCache. Those files will only be present if you have a caching plugin already installed. If you don't see them, you're ready to install ZenCache :-).

**A note for existing Quick Cache users:** ZenCache is the successor to Quick Cache and will automatically detect any existing Quick Cache options and migrate that options over to ZenCache. For further details, please see the [migration FAQ](http://zencache.com/kb-article/how-to-migrate-from-quick-cache-lite-to-zencache-lite/).

= ZenCache is Very Easy to Install =

1. Upload the `/zencache` folder to your `/wp-content/plugins/` directory.
2. Activate the plugin through the Plugins menu in WordPress®.
3. Navigate to the **ZenCache** panel & enable it.

= How will I know ZenCache is Working? =

First of all, make sure that you've enabled ZenCache. After you activate the plugin in WordPress, go to the ZenCache options panel and enable caching (you can't miss the big yellow checkbox). Then scroll to the bottom and click Save All Changes. All of the other options on that page are already pre-configured for typical usage. Skip them all for now. You can go back through all of these later and fine-tune things the way you like them.

Once ZenCache has been enabled, **you'll need to log out** (and/or clear browser cookies). Cache files are NOT served to visitors who are logged in, and that includes you too :-) Cache files are NOT served to recent commenters either. If you've commented (or replied to a comment lately); please clear your browser cookies before testing.

**To verify that ZenCache is working**, navigate your site like a normal visitor would. Right-click on any page (choose View Source), then scroll to the very bottom of the document. At the bottom, you'll find comments that show ZenCache stats and information. You should also notice that page-to-page navigation is lightning fast compared to what you experienced prior to installing ZenCache.

= Running ZenCache On A WordPress® Multisite Installation =

WordPress® Multisite Networking is a special consideration in WordPress®. If ZenCache is installed under a Multisite Network installation, it will be enabled for ALL blogs the same way. The centralized config options for ZenCache, can only be modified by a Super Administrator operating on the main site. ZenCache has internal processing routines that prevent configuration changes, including menu displays; for anyone other than a Super Administrator operating on the main site.

= EMERGENCY: If All Else Fails (How-To Remove ZenCache) =

Ordinarily you can just deactivate ZenCache from the plugins menu in WordPress. However, if you're having a more serious issue, please follow the instructions here.

1. Log into your site via FTP; perhaps using [FileZilla](http://www.youtube.com/watch?v=joXUMhr8PhU).
2. Delete this file: `/wp-content/advanced-cache.php`
3. Delete this directory: `/wp-content/plugins/zencache/`
4. Remove this line from your `/wp-config.php` file: `define('WP_CACHE', TRUE);`

ZenCache is now completely uninstalled and you can start fresh :-)

== Frequently Asked Questions ==

= I already have Quick Cache installed; how do I install ZenCache? =

ZenCache is the successor to Quick Cache and will automatically detect any existing Quick Cache options and migrate those options over to ZenCache. For further details, please see the [migration FAQ](http://zencache.com/kb-article/how-to-migrate-from-quick-cache-lite-to-zencache-lite/).

= How do I know that ZenCache is working the way it should be? =

First of all, make sure that you've enabled ZenCache. After you activate the plugin, go to the ZenCache options panel and enable it, then scroll to the bottom and click Save All Changes. All of the other options on that page are already pre-configured for typical usage. Skip them all for now. You can go back through all of them later and fine-tune things the way you like them.

Once ZenCache has been enabled, **you'll need to log out** (and/or clear browser cookies). Cache files are NOT served to visitors who are logged in, and that includes you too :-) Cache files are NOT served to recent commenters either. If you've commented (or replied to a comment lately); please clear your browser cookies before testing.

**To verify that ZenCache is working**, navigate your site like a normal visitor would. Right-click on any page (choose View Source), then scroll to the very bottom of the document. At the bottom, you'll find comments that show ZenCache stats and information. You should also notice that page-to-page navigation is lightning fast compared to what you experienced prior to installing ZenCache.

= What is the down side to running ZenCache? =

There is NOT one! ZenCache is a MUST HAVE for every WordPress® powered site. In fact, we really can't think of any site running WordPress® that would want to be without it. To put it another way, the WordPress® software itself comes with a built in action reference for an `advanced-cache.php` file, because WordPress® developers realize the importance of such as plugin. The `/wp-content/advanced-cache.php` file is named as such, because the WordPress® developers expect it to be there when caching is enabled by a plugin. If you don't have the `/wp-content/advanced-cache.php` file yet, it is because you have not enabled ZenCache from the options panel yet.

= So why does WordPress® need to be cached? =

To understand how ZenCache works, first you have to understand what a cached file is, and why it is absolutely necessary for your site and every visitor that comes to it. WordPress® (by its very definition) is a database-driven publishing platform. That means you have all these great tools on the back-end of your site to work with, but it also means that every time a Post/Page/Category is accessed on your site, dozens of connections to the database have to be made, and literally thousands of PHP routines run in harmony behind-the-scenes to make everything jive. The problem is, for every request that a browser sends to your site, all of these routines and connections have to be made (yes, every single time). Geesh, what a waste of processing power, memory, and other system resources. After all, most of the content on your site remains the same for at least a few minutes at a time. If you've been using WordPress® for very long, you've probably noticed that (on average) your site does not load up as fast as other sites on the web. Now you know why!

In computer science, a cache (pronounced /kash/) is a collection of data duplicating original values stored elsewhere or computed earlier, where the original data is expensive to fetch (owing to longer access time) or to compute, compared to the cost of reading the cache. In other words, a cache is a temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data.

= Where & why are the cache files stored on my server? =

The cache files are stored in a special directory: `/wp-content/cache/zencache`. This directory needs to remain writable, just like the `/wp-content/uploads` directory on many WordPress® installations. The `/zencache/cache` directory is where cache files reside. These files are stored using an intutive directory structure that named based on the request URL (`HTTPS/HTTP_HOST/REQUEST_URI`). See also: **Dashboard -› ZenCache -› Cache Directory/Expiration Time** for further details.

Whenever a request comes in from someone on the web, ZenCache checks to see if it can serve a cached file; e.g. it looks at the `HTTPS/HTTP_HOST/REQUEST_URI` environent variables, then it checks the `/zencache/cache` directory. If a cache file has been built already, and it matches an existing `HTTPS.HTTP_HOST.REQUEST_URI` combination; and it is not too old (see: **Dashboard -› ZenCache -› Cache Directory/Expiration Time**), then it will serve that file instead of asking WordPress® to regenerate it. This adds tremendous speed to your site and reduces server load.

If you have GZIP compression enabled, then the cache file is also sent to the browser with compression (recommended). Modern web browsers that support this technique will definitely take advantage of it. After all, if it is easier to email a zip file, it's also easier to download a web page that way. That is why on-the-fly GZIP compression for web pages is recommended. This is supported by all modern browsers.

If you want to enable GZIP, create an `.htaccess` file in your WordPress® installation directory and put the following few lines in it. Alternatively, if you already have an `.htaccess` file, just add these lines to it, and that is all there is to it. GZIP is now enabled!

	<IfModule deflate_module>
		<IfModule filter_module>
			AddOutputFilterByType DEFLATE text/plain text/html
			AddOutputFilterByType DEFLATE text/xml application/xml application/xhtml+xml application/xml-dtd
			AddOutputFilterByType DEFLATE application/rdf+xml application/rss+xml application/atom+xml image/svg+xml
			AddOutputFilterByType DEFLATE text/css text/javascript application/javascript application/x-javascript
			AddOutputFilterByType DEFLATE font/otf font/opentype application/font-otf application/x-font-otf
			AddOutputFilterByType DEFLATE font/ttf font/truetype application/font-ttf application/x-font-ttf
		</IfModule>
	</IfModule>

If your installation of Apache does not have `mod_deflate` installed. You can also enable GZIP compression using PHP configuration alone. In your `php.ini` file, you can simply add the following line anywhere: `zlib.output_compression = on`

= What happens if a user logs in? Are cache files used then? =

By default, ZenCache does NOT serve cached pages to users who are logged in, or to users who have left comments recently. ZenCache also excludes administrative pages, login pages, POST/PUT/DELETE/GET(w/ query string) requests and/or CLI processes. That being said, the Pro version of ZenCache DOES make it possible to cache pages even when users ARE logged-in; adding even more speed! This is particularly helpful on membership sites; e.g. sites that run plugins like s2Member™ for instance.

= Will comments and other dynamic parts of my blog update immediately? =

It depends on your configuration of ZenCache. There is an automatic expiration system (the garbage collector), which runs through WordPress® behind-the-scene, according to your Expiration setting (see: **Dashboard -› ZenCache -› Cache Directory/Expiration Time**). There is also a built-in expiration time on existing files that is checked before any cache file is served up, which also uses your Expiration setting. In addition; whenever you update a Post or a Page, ZenCache can automatically prune that particular file from the cache so it instantly becomes fresh again. Otherwise, your visitors would need to wait for the previous cached version to expire.

By default, ZenCache does NOT serve cached pages to users who are logged in, or to users who have left comments recently. ZenCache also excludes administrative pages, login pages, POST/PUT/DELETE/GET(w/ query string) requests and/or CLI processes.

= How do I enable GZIP compression? Is GZIP supported? =

There is no need to use an `.htaccess` file with this plugin; caching is handled by WordPress®/PHP alone. That being said, if you also want to take advantage of GZIP compression (and we do recommend this), then you WILL need an `.htaccess` file to accomplish that part. This plugin fully supports GZIP compression on its output. However, it does not handle GZIP compression directly. We purposely left GZIP compression out of this plugin, because GZIP compression is something that should really be enabled at the Apache level or inside your `php.ini` file. GZIP compression can be used for things like JavaScript and CSS files as well, so why bother turning it on for only WordPress-generated pages when you can enable GZIP at the server level and cover all the bases!

If you want to enable GZIP, create an `.htaccess` file in your WordPress® installation directory and put the following few lines in it. Alternatively, if you already have an `.htaccess` file, just add these lines to it, and that is all there is to it. GZIP is now enabled!

	<IfModule deflate_module>
		<IfModule filter_module>
			AddOutputFilterByType DEFLATE text/plain text/html
			AddOutputFilterByType DEFLATE text/xml application/xml application/xhtml+xml application/xml-dtd
			AddOutputFilterByType DEFLATE application/rdf+xml application/rss+xml application/atom+xml image/svg+xml
			AddOutputFilterByType DEFLATE text/css text/javascript application/javascript application/x-javascript
			AddOutputFilterByType DEFLATE font/otf font/opentype application/font-otf application/x-font-otf
			AddOutputFilterByType DEFLATE font/ttf font/truetype application/font-ttf application/x-font-ttf
		</IfModule>
	</IfModule>

If your installation of Apache does not have `mod_deflate` installed. You can also enable gzip compression using PHP configuration alone. In your `php.ini` file, you can simply add the following line anywhere: `zlib.output_compression = on`

= I'm a plugin developer. How can I prevent certain files from being cached? =

	<?php
	define('ZENCACHE_ALLOWED', FALSE); // The easiest way.
	// or $_SERVER['ZENCACHE_ALLOWED'] = FALSE; // Also very easy.
	// or define('DONOTCACHEPAGE', TRUE); // For compatibility with other cache plugins.

When your script finishes execution, ZenCache will know that it should NOT cache that particular page. It does not matter where or when you define this Constant; e.g. `define('ZENCACHE_ALLOWED', FALSE);` because ZenCache is the last thing to run during execution. So as long as you define this Constant at some point in your routines, everything will be fine.

ZenCache also provides support for `define('DONOTCACHEPAGE', TRUE)`, which is used by the WP Super Cache plugin as well. Another option is: `$_SERVER['ZENCACHE_ALLOWED'] = FALSE`. The `$_SERVER` array method is useful if you need to disable caching at the Apache level using `mod_rewrite`. The `$_SERVER` array is filled with all environment variables, so if you use `mod_rewrite` to set the `ZENCACHE_ALLOWED` environment variable, that will end up in `$_SERVER['ZENCACHE_ALLOWED']`. All of these methods have the same end result, so it's up to you which one you'd like to use.

= What should my expiration setting be? =

If you don't update your site much, you could set this to `6 months`; optimizing everything even further. The longer the cache expiration time is, the greater your performance gain. Alternatively, the shorter the expiration time, the fresher everything will remain on your site. A default value of `7 days` (recommended expiration time), is a good conservative middle-ground.

Keep in mind that your expiration setting is only one part of the big picture. ZenCache will also purge the cache automatically as changes are made to the site (i.e. you edit a post, someone comments on a post, you change your theme, you add a new navigation menu item, etc., etc.). Thus, your expiration time is really just a fallback; e.g. the maximum amount of time that a cache file could ever possibly live.

That being said, you could set this to just `60 seconds` and you would still see huge differences in speed and performance. If you're just starting out with ZenCache (perhaps a bit nervous about old cache files being served to your visitors); you could set this to something like `30 minutes` and experiment with it while you build confidence in ZenCache. It's not necessary, but many site owners have reported this makes them feel like they're more-in-control when the cache has a short expiration time. All-in-all, it's a matter of preference :-)

= EMERGENCY: If all else fails, how can I remove ZenCache? =

Ordinarily you can just deactivate ZenCache from the plugins menu in WordPress. However, if you're having a more serious issue, please follow the instructions here.

1. Log into your site via FTP; perhaps using [FileZilla](http://www.youtube.com/watch?v=joXUMhr8PhU).
2. Delete this file: `/wp-content/advanced-cache.php`
3. Delete this directory: `/wp-content/plugins/zencache/`
4. Remove this line from your `/wp-config.php` file: `define('WP_CACHE', TRUE);`

ZenCache is now completely uninstalled and you can start fresh :-)

== Further Details ==

= So Why Does WordPress® Need To Be Cached? =

To understand how ZenCache works, first you have to understand what a cached file is, and why it is absolutely necessary for your site and every visitor that comes to it. WordPress® (by its very definition) is a database-driven publishing platform. That means you have all these great tools on the back-end of your site to work with, but it also means that every time a Post/Page/Category is accessed on your site, dozens of connections to the database have to be made, and literally thousands of PHP routines run in harmony behind-the-scenes to make everything jive. The problem is, for every request that a browser sends to your site, all of these routines and connections have to be made (yes, every single time). Geesh, what a waste of processing power, memory, and other system resources. After all, most of the content on your site remains the same for at least a few minutes at a time. If you've been using WordPress® for very long, you've probably noticed that (on average) your site does not load up as fast as other sites on the web. Now you know why!

= The Definition Of A Cached File (from the Wikipedia) =

In computer science, a cache (pronounced /kash/) is a collection of data duplicating original values stored elsewhere or computed earlier, where the original data is expensive to fetch (owing to longer access time) or to compute, compared to the cost of reading the cache. In other words, a cache is a temporary storage area where frequently accessed data can be stored for rapid access. Once the data is stored in the cache, it can be used in the future by accessing the cached copy rather than re-fetching or recomputing the original data.

= Prepare To Be Amazed / It's Time To Speed Things Up =

ZenCache is extremely reliable, because it runs completely in PHP code, and does not hand important decisions off to the `mod_rewrite` engine or browser cache; also making ZenCache MUCH easier to setup and configure.

In addition, ZenCache actually sends a no-cache header (yes, a no-cache header); which allows it to remain in control at all times. It might seem weird that a caching plugin would send a no-cache header :-). Well, no-cache headers are a key component in this plugin, and they will NOT affect performance negatively. On the contrary, this is how the system can accurately serve cache files to public users vs. users who are logged-in, commenters, etc.

If you care about the speed of your site, ZenCache is one of those plugins that you absolutely MUST have installed :-) ZenCache takes a real-time snapshot (building a cache) of every Page, Post, Category, Link, etc. These snapshots are then stored (cached) intuitively, so they can be referenced later, in order to save all of that processing time that has been dragging your site down and costing you money.

The ZenCache plugin uses configuration options that you select from the options panel. See: **ZenCache -› Options** in your Dashboard. Once a file has been cached, ZenCache uses advanced techniques that allow it to recognize when it should and should not serve a cached version of the file. By default, ZenCache does not serve cached pages to users who are logged in, or to users who have left comments recently. ZenCache also excludes administrative pages, login pages, POST/PUT/DELETE/GET(w/ query string) requests and/or CLI processes.

= Running ZenCache On A WordPress® Multisite Installation =

WordPress® Multisite Networking is a special consideration in WordPress®. If ZenCache is installed under a Multisite Network installation, it will be enabled for ALL blogs the same way. The centralized config options for ZenCache, can only be modified by a Super Administrator operating on the main site. ZenCache has internal processing routines that prevent configuration changes, including menu displays; for anyone other than a Super Administrator operating on the main site.

= How To Enable GZIP Compression for Even Greater Speeds =

You don't have to use an `.htaccess` file to enjoy the performance enhancements provided by this plugin; caching is handled by WordPress®/PHP alone. That being said, if you want to take advantage of GZIP compression (and we do recommend this), then you WILL need an `.htaccess` file to accomplish that part. This plugin fully supports GZIP compression on its output. However, it does not handle GZIP compression directly. We purposely left GZIP compression out of this plugin, because GZIP compression is something that should really be enabled at the Apache level or inside your `php.ini` file. GZIP compression can be used for things like JavaScript and CSS files as well, so why bother turning it on for only WordPress-generated pages when you can enable GZIP at the server level and cover all the bases!

If you want to enable GZIP, create an `.htaccess` file in your WordPress® installation directory and put the following few lines in it. Alternatively, if you already have an `.htaccess` file, just add these lines to it, and that is all there is to it. GZIP is now enabled!

	<IfModule deflate_module>
		<IfModule filter_module>
			AddOutputFilterByType DEFLATE text/plain text/html
			AddOutputFilterByType DEFLATE text/xml application/xml application/xhtml+xml application/xml-dtd
			AddOutputFilterByType DEFLATE application/rdf+xml application/rss+xml application/atom+xml image/svg+xml
			AddOutputFilterByType DEFLATE text/css text/javascript application/javascript application/x-javascript
			AddOutputFilterByType DEFLATE font/otf font/opentype application/font-otf application/x-font-otf
			AddOutputFilterByType DEFLATE font/ttf font/truetype application/font-ttf application/x-font-ttf
		</IfModule>
	</IfModule>

If your installation of Apache does not have `mod_deflate` installed. You can also enable GZIP compression using PHP configuration alone. In your `php.ini` file, you can simply add the following line anywhere: `zlib.output_compression = on`

= EMERGENCY: If All Else Fails (How-To Remove ZenCache) =

Ordinarily you can just deactivate ZenCache from the plugins menu in WordPress. However, if you're having a more serious issue, please follow the instructions here.

1. Log into your site via FTP; perhaps using [FileZilla](http://www.youtube.com/watch?v=joXUMhr8PhU).
2. Delete this file: `/wp-content/advanced-cache.php`
3. Delete this directory: `/wp-content/plugins/zencache/`
4. Remove this line from your `/wp-config.php` file: `define('WP_CACHE', TRUE);`

ZenCache is now completely uninstalled and you can start fresh :-)

== Pro Features ==

= ZenCache Pro Features =

- The ability to cache logged-in users too! (VERY powerful, particularly for membership sites).
- A new improved "Clear Cache" button in the admin bar (along with an option to enable/disable this feature).
- The ability to disable Dashboard notifications related to automatic clearing/purging on change detections.
- The ability to clear Markdown-related cache files generated by the s2Clean theme for WordPress (if installed).
- The ability to run custom PHP code whenever the cache is cleared.
- Cache Statistics to help you gain insight into the status of your site cache.
- Import/Export functionality for ZenCache configuration files.
- A Dynamic Version Salt (customize the caching engine).
- HTML Compressor to automatically combine and compresses CSS/JS/HTML code.
- Auto-Cache Engine to pre-cache your site at 15-minute intervals.
- Static CDN Filters to serve some and/or ALL static files on your site from a CDN of your choosing, including support for Multiple CDN Host Names, Domain Sharding, and WordPress Multisite Networks.
- An Automatic Updater to update ZenCache Pro from your WordPress Dashboard.
- Rockstar support for all ZenCache features.

**TIP:** you can preview Pro features in the free version by clicking the "**Preview Pro Features**" link at the top of your ZenCache options.

== Pro Installation ==

ZenCache Pro is a wholly contained plugin that _does not_ require ZenCache Lite to be installed. To install ZenCache Pro,

1. Deactivate and delete ZenCache Lite, if it is currently installed
1. Download ZenCache Pro from your account at WebSharks-Inc.com
1. From your WordPress Dashboard, go to **Dashboard -> Plugins -> Add New** and then click on the **Upload Plugin** button at the top
1. Select the ZenCache Pro zip file you downloaded in step 2 and click "Install Now"
1. After the plugin finishes installing, click the "Activate Plugin" link

Once the plugin is active, you can go to **Dashboard -> ZenCache -> Plugin Options -> Enable/Disable** and Enable ZenCache.

Also, to stay updated with the latest version of ZenCache Pro, be sure to also configure **Dashboard -> ZenCache -> Plugin Updater**.

== Software Requirements ==

In addition to the [WordPress Requirements](http://wordpress.org/about/requirements/), ZenCache requires the following minimum versions:

- PHP 5.4+
- Apache 2.1+

== License ==

Copyright: © 2013 [WebSharks, Inc.](http://www.websharks-inc.com/bizdev/) (coded in the USA)

Released under the terms of the [GNU General Public License](http://www.gnu.org/licenses/gpl-2.0.html).

= Credits / Additional Acknowledgments =

* Software designed for WordPress®.
	- GPL License <http://codex.wordpress.org/GPL>
	- WordPress® <http://wordpress.org>
* Some JavaScript extensions require jQuery.
	- GPL-Compatible License <http://jquery.org/license>
	- jQuery <http://jquery.com/>
* CSS framework and some JavaScript functionality provided by Bootstrap.
	- GPL-Compatible License <http://getbootstrap.com/getting-started/#license-faqs>
	- Bootstrap <http://getbootstrap.com/>
* Icons provided by Font Awesome.
	- GPL-Compatible License <http://fortawesome.github.io/Font-Awesome/license/>
	- Font Awesome <http://fortawesome.github.io/Font-Awesome/>

== Upgrade Notice ==

= v160222 =

- Requires PHP v5.4+. As announced in the previous release, the minimum PHP version required to run ZenCache / Comet Cache has changed to PHP 5.4+ as of December 1st, 2015. Please see announcement with further details: [New Minimum PHP Version: PHP 5.4](http://zencache.com/r/new-minimum-php-version-php-5-4/)
- PHP APC Extension not supported. This version of ZenCache does not support the PHP APC Extension. As announced in the previous release, ZenCache / Comet Cache no longer runs with the PHP APC extension enabled as of December 1st, 2015. Please see announcement with further details: [PHP APC Extension No Longer Supported](http://zencache.com/r/php-apc-extension-no-longer-supported/)

== Changelog ==

= v160316 =

- **2nd Announcement: ZenCache has changed its name to Comet Cache!** Learn more about this change [here](https://cometcache.com/r/announcing-comet-cache-formerly-zencache/) and read the [migration instructions](https://cometcache.com/r/zencache-migration-faq/). Note that ZenCache will no longer be maintained after March 31st, 2016.

= v160222 =

- **Announcement: ZenCache is changing its name to Comet Cache!** Learn more about this upcoming change [here](https://cometcache.com/r/announcing-comet-cache-formerly-zencache/).
- **Announcement: This version of ZenCache requires PHP 5.4+.** As announced in the previous release, the minimum PHP version required to run ZenCache / Comet Cache has changed to PHP 5.4+ as of December 1st, 2015. Please see announcement with further details: [New Minimum PHP Version: PHP 5.4](http://zencache.com/r/new-minimum-php-version-php-5-4/)
- **Announcement: This version of ZenCache does not support the PHP APC Extension**. As announced in the previous release, ZenCache / Comet Cache no longer runs with the PHP APC extension enabled as of December 1st, 2015. Please see announcement with further details: [PHP APC Extension No Longer Supported](http://zencache.com/r/php-apc-extension-no-longer-supported/)
- **Announcement: After March 1st, 2016 ZenCache / Comet Cache will require PHP Multibyte String support.** The `mbstring` extension provides Multibyte String support to PHP and is required to properly handle UTF-8 characters, which many sites now use. Without Multibyte String support, caching will be unstable. For that reason we are requiring the `mbstring` extension to improve reliability when caching and to prevent your site from experiencing unforeseen issues in the future.
- **Announcement: Restructured Codebase**. The entire ZenCache Lite codebase has been restructured to improve performance, enhance flexibility, and make it easier to build in new features! This release of ZenCache Lite has been built from the ZenCache Pro codebase, which is more polished and up-to-date. This release includes many changes and improvements that were released as part of ZenCache Pro releases over the past 6 months and are now being included in the Lite version. See the full changelog below for a complete list of changes.
- **New Feature!** A new watered-down Regular Expression syntax is now supported in several existing ZenCache features, including XML Sitemap Patterns, URI Exclusion Patterns, HTTP Referrer Exclusion Patterns, and User-Agent Exclusion Patterns. (It is also supported in the Pro-only Custom URLs to Auto-Clear, and the HTML Compressor CSS Exclusion Patterns and JavaScript Exclusion Patterns.) This new syntax greatly increases the power and flexibility of each of these features and makes things possible like the much-requested ability to Auto-Clear the Home Page or Posts Page of a site whenever a post cache is cleared. For more information on this new watered-down Regular Expression syntax, [this KB Article](http://zencache.com/r/watered-down-regex-syntax/). Props @kristineds @jaswsinc. See [Issue #191](wpsharks/comet-cache#191).
- **Bug Fix**: Fixed a bug with clearing cache files for paginated pages where the `pagination_base` had been changed from the default `page` to something else (e.g., a translated string). The WP Rewrite API is now used to include `pagination_base` and `comments_pagination_base` when building paths to cache files to determine which cache files should be cleared. Props @renzms. See [Issue #607](wpsharks/comet-cache#607).
- **Bug Fix**: This release attempts to resolve reports of Error 500 and Internal Server Error issues when running with PHP 5.6 + OPcache. Instead of clearing the entire Opcode cache whenever the plugin options are saved, we only invalidate the `advanced-cache.php` file, which is rebuilt each time you update your configuration options. Props @jaswsinc. Also props to @MarioKnight and @CotswoldPhoto for helping us narrow this down. See [Issue #624](wpsharks/comet-cache#624).
- **Bug Fix**: Fixed an issue where a PHP Notice was generated when an inactive WordPress component was being upgraded. This issue did not have any adverse affect on the site, but this fix resolves the issue so that the notice won't appear in PHP logs. See [Issue #589](wpsharks/comet-cache#589).
- **Bug Fix**: Fixed a bug where a commented-out `WP_CACHE` definition in `wp-config.php` (such as what WP Super Cache leaves behind) was being incorrectly ignored and resulted in caching being silently disabled. Props @davidfavor. See [Issue #591](wpsharks/comet-cache#591).
- **Bug Fix**: Fixed a bug where in some scenarios a page might not be cached due to a stray `AUTH_COOKIE` or `SECURE_AUTH_COOKIE` cookie, even when the user is not logged in. Props @jaswsinc @renzms. See [Issue #592](wpsharks/comet-cache#592).
- **Bug Fix**: Fixed an issue related to a popular NGINX server configuration (`try_files $uri $uri/ /index.php?q=$uri&$args;`) that was preventing the entire site from being cached. ZenCache disables caching by default for all requests that include a query string (see _Dashboard → ZenCache → Plugin Options → GET Requests_) and this particular NGINX configuration passes _all_ requests to WordPress with a `?q=` query variable, which was resulting in ZenCache disabling caching on all pages. This release implements better detection for NGINX and works around this scenario. Props @jaswsinc. See [Issue #561](wpsharks/comet-cache#561).
- **Bug Fix**: Fixed a bug where, in some rare cases, `wp-config.php` would end up with two `WP_CACHE` definitions. Props @jaswsinc. See [Issue #509](wpsharks/comet-cache#509).
- **Bug Fix**: Saving a Post as a Draft was incorrectly purging XML Sitemap cache files. Props @jaswsinc. See [Issue #368](wpsharks/comet-cache#368).
- **Bug Fix**: Fixed a bug in the Dynamic Version Salt filter that was generating PHP notices and warnings. See [Issue #522](wpsharks/comet-cache#522).
- **Bug Fix**: Fixed an issue with backwards compatibility that was preventing some AC Plugins from working properly. See [Issue #514](wpsharks/comet-cache#514).
- **Bug Fix**: Fixed a bug where saving a Post/Page as a Draft as a user with an Editor role would unnecessarily clear the Home Page cache. See [Issue #625](wpsharks/comet-cache#625).
- **Multisite Bug Fix**: Fixed a bug where the Clear Cache button wouldn't clear Child-Site Logged-In User Home Page cache files on WordPress Multisite Networks. Props @jaswsinc. See [Issue #409](wpsharks/comet-cache#409)
- **Multisite Bug Fix**: Fixed a bug where the Home Page cache was not clearing on Child Sites in a Multisite Network. Props @jaswsinc. See [Issue #409](wpsharks/comet-cache#409)
- **Multisite Bug Fix**: Fixed a bug with 404 Request caching on Multisite Networks where ZenCache Pro was not considering that each child blog in a multisite network will have its own 404 error page. Props @jaswsinc. See [Issue #539](wpsharks/comet-cache#539).
- **Multisite Bug Fix**: Fixed a bug where clearing the cache from the main site of a multisite network, when there are child blogs in sub-directories, resulted in all child blogs being cleared from the cache, not just the main site as would be expected. This has been resolved and only the main site is cleared when clicking the Clear Cache button. Note that the Wipe Cache button can still be used to clear the cache for all sites in a Multisite Network. Props @jaswsinc. See [Issue #540](wpsharks/comet-cache#540).
- **Multisite Bug Fix**: Fixed a bug where Wiping the cache on a multisite network resulted in the very next page view being cached incorrectly. Props @jaswsinc. See [Issue #541](wpsharks/comet-cache#541).
- **Multisite Bug Fix**: Fixed a bug where when ZenCache was Network Activated the plugin settings link would show up in the plugins list for the Main Site and would lead to a 404 error. The settings link is now only shown when viewing the plugins list from the Network Admin. Props @jaswsinc. See [Issue #675](wpsharks/comet-cache#675).
- **Enhancement**: Added support-related links to the plugin options page. Props @renzms. See [Issue #612](wpsharks/comet-cache#612 (comment)).
- **Enhancement**: It's now possible to override the ZenCache Nonce exclusion globally (dangerous) or only for Logged-In Users (safer). Please see [this article](http://zencache.com/r/kb-article-what-are-wordpress-nonces-and-why-are-they-not-cache-compatible/) for full details. [Issue #637](wpsharks/comet-cache#637).
- **Enhancement**: Improved WP Cron-related configuration and validation of custom cron schedules. See [PR #197](wpsharks/comet-cache-pro#197).
- **Enhancement**: ZenCache now clears the cache whenever a WordPress plugin is activated or deactivated. Many WordPress plugins change content on the front-end of the site, so this enhancement ensures that an old cache file is never served to visitors. If you want to disable this automatic behavior, see [this article](http://zencache.com/kb-article/how-do-i-prevent-zencache-from-clearing-the-cache-upon-plugin-activation-or-deactivation/). Props @renzms. See [Issue #424](wpsharks/comet-cache#424).
- **Enhancement**: When activating ZenCache for the first time, a new Dashboard message now includes a helpful link to the options page to enable caching and review the options. Props @kristineds. See [Issue #112](wpsharks/comet-cache#112).
- **Enhancement**: The automatic Cache Cleanup schedule that cleans up (deletes) expired/stale cache files has been changed from once every day to once every hour. Running the cleanup hourly makes ZenCache smarter when configured in certain ways and saves disk space. Props @kristineds. See [Issue #472](wpsharks/comet-cache#472).
- **Enhancement**: When the Cache Directory location is changed, ZenCache now cleans up the old Cache Directory and any old cache files instead of leaving them behind. Props @clavaque @renzms. See [Issue #580](wpsharks/comet-cache#580).
- **Enhancement**: Added a new API Function that allows a site owner to clear the cache for a specific URL via `zencache::clearUrl($url);`. See [this article](http://zencache.com/kb-article/clearing-the-cache-dynamically/#toc-988085ad) for further details. Props @kristineds. See [Issue #590](wpsharks/comet-cache#590).
- **Enhancement**: Improved the HTML Notes generated by ZenCache when s2Member (a membership plugin for WordPress) is specifically disabling caching. s2Member automatically disables caching on certain pages that are required to remain dynamic. The HTML Notes generated by ZenCache now explain when this is happening. Props @renzms. See [Issue #504](wpsharks/comet-cache#504).
- **Enhancement**: Manual Cache Clearing options have now been separated from Automatic Cache Clearing options inside the ZenCache Plugin Options to improve the differentiation between these.
- **Enhancement**: New icons in the ZenCache Plugin Options help improve the visual representation of each panel.
- **Enhancement**: The installed plugin version is now shown at the top of the ZenCache Options Page. Props @renzms. See [Issue #502](wpsharks/comet-cache#502).
- **Enhancement**: New transition in/out effects on the Cache Cleared Dashboard notifications. Props @jaswsinc. See [Issue #538](wpsharks/comet-cache#538).
- **Enhancement**: Improved compatibility with any Custom Post Type that uses hierarchies. Props @jaswsinc.
- **Akismet Compatibility:** ZenCache no longer caches pages that contain `akismet_comment_nonce` in the markup. This ensures that a page that contains a time-sensitive `nonce` value does not get cached. Props @kristineds and @jaswsinc. See [Issue #601](wpsharks/comet-cache#601).
- **Akismet Compatibility:** ZenCache now automatically disables the Akismet Comment Nonce using [the `akismet_comment_nonce` filter](https://github.com/git-mirror/wordpress-akismet/blob/2.5.6/akismet.php#L333), which improves compatibility between Akismet and the page caching functionality provided by ZenCache. This ensures that pages do not contain time-sensitive `nonce` values that should not be cached. If you'd like to revert this behavior, please see [this article](http://zencache.com/kb-article/how-do-i-prevent-zencache-from-disabling-the-akismet-comment-nonce/). Props @kristineds and @jaswsinc. See [Issue #601](wpsharks/comet-cache#601).
- **Akismet Compatibility**: Fixed a bug with Akismet compatibility where ZenCache was not properly disabling the Akismet Comment Nonce, which resulted in pages being unnecessarily excluded from the cache due to the presence of the `akismet_comment_nonce` in the markup. Props @Kalfer. See [Issue #642](wpsharks/comet-cache#642).
- **WooCommerce Compatibility:** This release improves compatibility with the WooCommerce Product Stock feature. When the Product Stock changes, ZenCache will now clear the cache file for the associated Product to ensure that the stock quantity that appears on the site remains up-to-date. See [Issue #597](wpsharks/comet-cache#597).
- **Multisite Domain Mapping Compatibility**: ZenCache is now fully compatible with the [WordPress MU Domain Mapping plugin](https://wordpress.org/plugins/wordpress-mu-domain-mapping/), including Multisite Networks using domain mapping on top-level domains, sub-domains, and sub-directories. Multiple variations of each site spread across an unlimited number of domain mappings and/or the original blog domain/path is also supported. All Pro-only features, including the Auto-Cache Engine, Static CDN Filters, and HTML Compression, are also now compatible with domain mapping. Props @jaswsinc. See [Issue #339](wpsharks/comet-cache#339).
- **bbPress Compatibility**: This release greatly improves compatibility with bbPress. Events like creating a new Forum, creating a new Topic, and posting a reply to a Topic (including threaded replies), now properly clear the necessary cache files to ensure that cached bbPress pages remain up-to-date. Props @jaswsinc. See [Issue #168](wpsharks/comet-cache#168).
- **bbPress Compatibility:** This release improves compatibility with bbPress when ZenCache Logged-In User caching is enabled. In this scenario, bbPress may generate links for Admins that contain time-sensitive `_wpnonce` values which could expire if cached and result in certain admin-related actions failing. ZenCache no longer caches pages that contain `_wpnonce` in the markup. This ensures that pages containing time-sensitive `nonce` values are not cached. Props @kristineds, @jaswsinc, and @clavaque. See [Issue #601](wpsharks/comet-cache#601).
- **New Pro Features:** This release updates the Pro Preview to include several new Pro features that have been added over the past 6 months, including the ability to clear the PHP OPCache whenever manually clearing the cache (_ZenCache Options → Manual Cache Clearing → Clear the PHP OPCache Too?_), clear the CDN Cache whenever manually clearing the cache (_ZenCache Options → Manual Cache Clearing → CDN Cache Clear the CDN Cache Too?_), disable cache expiration if the server load average is high (_ZenCache Options → Cache Expiration Time → Disable Cache Expiration If Server Load Average is High_), the ability to specify which WordPress Roles/Capabilities are allowed to clear the cache from the WordPress Admin bar (_ZenCache Options → Manual Cache Clearing → Also allow others to clear the cache from their Admin Bar?_), a completely new Cache Statistics feature that allows you to monitor the health and status of your cache (_ZenCache → Stats / Charts_), the ability to specify a list of Custom URLs whose cache files should be cleared whenever ZenCache detects that a Post/Page cache should be cleared (_ZenCache Options → Automatic Cache Clearing → Misc. Auto-Clear Options → Auto-Clear a List of Custom URLs Too?_), a new menu of Clear Cache options in the Admin Bar that allows you to  clear the cache for just the Home Page, the Current URL, a Specific URL, PHP's OPCache, or the CDN Cache (_ZenCache Options → Plugin Options → Manual Cache Clearing_), the ability to customize the Cache Cleanup Schedule and set your own schedule (_ZenCache Options → Manual Cache Clearing → Cache Cleanup Schedule_), the ability to configure the Pro Plugin Updater to check for Beta versions, an option to clear Expired WordPress Transients, and URI Exclusion Patterns for Client-Side Caching.

= v160103 =

- **Bug Fix**: Fixed an issue that was unexpectedly producing "Failed to update your /.htaccess file" error messages. The `.htaccess` routines are now more intelligent and take into consideration which plugin options are enabled and which options require updating the `.htaccess` file. This also improves performance by avoiding unnecessary read/writes to the `.htaccess` file. Props @patdumond. See [Issue #641](wpsharks/comet-cache#641).
- **Bug Fix**: When `allow_url_fopen` is disabled via the PHP configuration, the Auto-Cache Engine is unable to read the XML Sitemap and was silently failing with only PHP Warning in the PHP error log. The Auto-Cache Engine currently requires [PHP URL-aware fopen wrappers](http://zencache.com/r/allow_url_fopen/). A new Dashboard notice displays an error message when `allow_url_fopen` is disabled and prevents the Auto-Cache Engine from attempting to run. See [Issue #644](wpsharks/comet-cache#644).
- **Bug Fix**: Fixed an Auto-Cache Engine bug that was producing false-positive Dashboard errors related to timeouts: "Problematic XML Sitemap URL - WP_Http says: Operation timed out after 5001 milliseconds with 0 bytes received." Due to the way ZenCache was checking the XML Sitemap URL more than necessary, timeouts were more likely to occur. We now only check the URL repeatedly when a failure has been encountered. If the URL is confirmed as working, we don't check the URL again until the Auto-Cache Engine runs (every 15 minutes by default) or until the Plugin Options are saved. If you are still seeing timeout errors after this update, please see [this article](http://zencache.com/kb-article/why-am-i-seeing-auto-cache-engine-timeout-errors/). See [Issue #643](wpsharks/comet-cache#643).
- **Bug Fix**: Fixed an Auto-Cache Engine bug where ZenCache would would check both the non-SSL (`http://`) and the SSL (`https://`) version of the XML Sitemap URL when the Site Address was configured to use SSL. See [Issue #643](wpsharks/comet-cache#643).
- **Enhancement**: It's now possible to override the ZenCache Nonce exclusion globally (dangerous) or only for Logged-In Users (safer). Please see [this article](http://zencache.com/r/kb-article-what-are-wordpress-nonces-and-why-are-they-not-cache-compatible/) for full details. [Issue #637](wpsharks/comet-cache#637).
- **Akismet Compatibility**: Fixed a bug with Akismet compatibility where ZenCache was not properly disabling the Akismet Comment Nonce, which resulted in pages being unnecessarily excluded from the cache due to the presence of the `akismet_comment_nonce` in the markup. Props @Kalfer. See [Issue #642](wpsharks/comet-cache#642).

For older Changelog entries, please see the `CHANGELOG.md` file.