Thorsten Frommen

Register page keys, assign WordPress pages to them, and access each of these pages by its individual key.
Have you ever wanted to access a specific page from inside a template file? Of course, you could query it by its title. But what if someone wanted to rename the page? Okay, so we choose the slug. But maybe that someone also thought editing the slug as well to make it fit the new title was a very good idea. Yes, I know, it is not. But that someone either didn’t know, or didn’t care. Okay, so let’s use the page ID. Oh, wait, now that someone, by mistake, permanently deleted that page. After having visited the frontend that someone created a new page, with the exact same title and the exact same slug as the original page. But that damn page still won’t show.
This is exactly when Page Keys kicks in.
<h4>Usage</h4>
What this plugin is all about is providing a means to accessing specific pages by unique and therefore individual keys. And doing this is quite simple. On the Page Keys admin page, you can add as many unique page keys as you like. For each of these page keys, you then select a (published) page. Hit the Save Changes button, and you’re done already.
Suppose you now want to access a specific page in one of your theme’s template file. After having defined a page key and having assigned a page to it, you can get the according <code>WP_Post</code> object by calling <code>get_page_by_key( $key )</code>. In the rare case where you already have a function of that name defined within the global namespace, you would have to set up such a function by yourself. In principle, this is just a copy of what you can find in the <code>functions.php</code> file of this plugin.
Filters
In order to customize certain aspects of the plugin, it provides you with several filters. For each of these, a short description as well as a code example on how to alter the default behavior is given below. Just put the according code snippet in your theme’s <code>functions.php</code> file or your customization plugin, or to some other appropriate place.
<code>edit_page_keys_capability</code>
Editing the page keys is restricted to a certain capability, which is by default <code>edit_published_pages</code>. The reason for this choice lies with the fact that user, who is capable of editing a published page (e.g., changing its status to <code>draft</code>), implicitly is able to compromise any page key mapped to the page.
<pre><code>/**
 * Filter the capability required to edit the page keys.
 *
 * @param string $capability Capability required to edit the page keys.
 */
add_filter( 'edit_page_keys_capability', function() {

 return 'manage_options';
} );
</code></pre>
<code>list_page_keys_capability</code>
Accessing the plugin’s settings page is restricted, too. In order to distinguish between users who are only allowed to see the existing page keys as well as their respective page, and users, who are able to edit page keys, there are two individual capabilities. The default for accessing the settings page is <code>edit_pages</code>.
<pre><code>/**
 * Filter the capability required to list the page keys.
 *
 * @param string $capability Capability required to list the page keys.
 */
add_filter( 'list_page_keys_capability', function() {

 return 'read';
} );
</code></pre>
<code>page_keys_show_admin_notice</code>
Depending on how exactly you are working with the plugin, the admin notice informing you about page keys that don’t have a page assigned might be more annoying than helping. Gladly, there is a filter to turn this off.
<pre><code>add_filter( 'page_keys_show_admin_notice', '__return_false' );
</code></pre>
<h4>Contribution</h4>
To contribute to this plugin, please see its <a href="https://github.com/tfrommen/page-keys" rel="nofollow ugc">GitHub repository</a>.
If you have a feature request, or if you have developed the feature already, please feel free to use the Issues and/or Pull Requests section.
Of course, you can also provide me with translations if you would like to use the plugin in another not yet included language.

Page Keys

Register page keys, assign WordPress pages to them, and access each of these pages by its individual key.

banderon

Gives functions to use to generate strings to use as keys for caching. Keys are generated based on a passed in name and 
zero or more groups. Providing the same name and groups will return the same key until the entire cache is cleared 
or the cache for a specific group name is cleared.
<h3>Usage</h3>
$key: STRING 
$groups: STRING|ARRAY
<pre><code><?php
if ( class_exists( 'Voce_Group_Keys' ) ) {

 // Get a key for $key that is in the $groups group(s)
 voce_get_cache_key( $key, $groups );

 // Clear the keys for $groups
 // If multiple groups are specified, keys in any of the specified groups will be cleared
 voce_clear_group_cache( $groups );

 // Clear all keys
 voce_clear_all_group_cache();
}
</code></pre>
<h4>Example 1</h4>
<pre><code><?php
if ( class_exists( 'Voce_Group_Keys' ) ) {

 // Get a key without a group
 echo voce_get_cache_key( 'data' ); // data_4942b011eb

 // Get keys in a single group
 echo voce_get_cache_key( 'data', 'people' ); // data_9915443f5c
 echo voce_get_cache_key( 'more-data', 'people' ); // more-data_9915443f5c

 // The same key will be returned
 echo voce_get_cache_key( 'data', 'people' ); // data_9915443f5c

 // Clear keys in the 'people' group
 voce_clear_group_cache( 'people' );

 // After clearing keys, a new key is returned for keys using that group
 echo voce_get_cache_key( 'data', 'people' ); // data_77j18e728
 echo voce_get_cache_key( 'data' ); // data_4942b011eb

}
</code></pre>
<h4>Example 2</h4>
<pre><code><?php
if ( class_exists( 'Voce_Group_Keys' ) ) {

 // Set transients using multiple groups
 echo voce_get_cache_key( 'user-data', 'users' ); // user-data_9915443f5c
 echo voce_get_cache_key( 'post-data', 'posts' ); // post-data_85fb002156
 echo voce_get_cache_key( 'user-post-data', array( 'posts', 'users' ) ); // user-post-data_4aee2c2c89

 // Clear any keys using the 'posts' group
 voce_clear_group_cache( 'posts' );

 // New keys returned for anything in the 'posts' group
 echo voce_get_cache_key( 'user-data', 'users' ); // user-data_9915443f5c
 echo voce_get_cache_key( 'post-data', 'posts' ); // post-data_820dd0dfb0
 echo voce_get_cache_key( 'user-post-data', array( 'posts', 'users' ) ); // user-post-data_b7ac93f802

 // The order of groups is irrelevant
 echo voce_get_cache_key( 'user-post-data', array( 'users', 'posts' ) ); // user-post-data_b7ac93f802

 // Clear any keys in either the 'users' or 'posts' groups
 voce_clear_group_cache( array( 'users', 'posts' ) );

 // Clear all keys
 voce_clear_all_group_cache();
}
</code></pre>

Voce Group Keys

Create string keys for caching based off of specified groups, allowing clearing keys based on the groups to which they belong.

Page Keys vs Voce Group Keys