Activate and Deactivate Theme hooks

[jacobsantos]

Currently, there is no standard way of checking whether of theme is activated, deactivated and uninstalled. Plugins have this capability and themes should also have the same to ensure that both share similar functionality.

Marked #7556 as duplicate of this.

See also:  http://comox.textdrive.com/pipermail/wp-hackers/2008-August/021298.html (from the other ticket)

See also #8652.

Hm.. Just started implementing this.

How to handle theme activation.. It would be possible to include both themes at once, that would be the simplest way, but could cause issues if themes duplicate functions.

could run the activation hook on the page reload, so that only 1 theme is included at once.. Thoughts?

attachment 7795.diff added.

• Downside: Theme activation hooks are only run if the theme is activated via the theme panel, Other custom methods will need to call the run_theme_activation_hook() function manually after including the theme.
• uses register_theme_activation_hook(__FILE__, 'function') and register_theme_deactivation_hook(__FILE__, 'function') syntax, Must be called from a file within the themes directory, but NOT in a subdirectory.
• Activation hook is run on a page refresh, So activation has 2 redirects, It would be possible to remove the wp_redirect() and exit lines from the theme_activate if block, but the URL would be messy, and any output from the themes activation function would be shown.. Seemed best to redirect again

Example use: (in a themes functions.php)

add_action('generate_rewrite_rules', 'theme_add_rewrite_rules', 100);
function theme_add_rewrite_rules( $wp_rewrite ) {
	$new_rules = array( '^redirect-me/?$' => 'index.php?pagename=to-something-else' );
	$wp_rewrite->rules = $new_rules + (array)$wp_rewrite->rules;
}

register_theme_activation_hook(__FILE__, 'theme_activate');
function theme_activate() {
	global $wp_rewrite;
	$wp_rewrite->flush_rules();
}

register_theme_deactivation_hook(__FILE__, 'theme_deactivate');
function theme_deactivate() {
	global $wp_rewrite;
	remove_action('generate_rewrite_rules', 'theme_add_rewrite_rules', 100);
	$wp_rewrite->flush_rules();
}

(Hope you dont mind me clearing the assigned status jacobsantos)

I don't mind you replacing me as the assigned, since you've done the most work anyway. I just like being able to track tickets without having to do a search for 'cc' or reporter. I always seem to forget which on I've used.

I don't see why the functions need to be in the themes directory and not a subdirectory. It appears to work just like the plugins activation and deactivation hook. You are hooking into the file name of the main theme, in which case it will always be THEME_NAME/functions.php, which does make it easier. It means that they'll just have to include the file that has those functions in their main file.

This weekend I think I'm going to test it and see how it goes. Hopefully more people will test it.

You are hooking into the file name of the main theme, in which case it will always be THEME_NAME/functions.php

Errr... 'doh! Here was I thinking i needed to check which theme it was coming from -- Err, Actually, You do need to. In the case of a child and parent theme, you'd want both activation hooks to run, and as such, you'd need to be able to tell which one is calling.

The reason for the "must be in theme root" was because of the __FILE__ -> theme name, __FILE__ returns c:\...\..\ on windows, and the Theme dir constant is C:\...\..../wp-content/..... so a simple str_replace and all that would need to be done, And i was thinking of optimization at the time, its code thats potentially going to run on every page load (I guess a !is_admin() line could short circuit it?

The other option would've been to do:

$theme = preg_replace('|^.*/themes/|', '', dirname($file));
$theme = preg_replace('|[/\\\].*$|', '', $theme);

OR
$theme = preg_replace('|^.*/themes/|', '', dirname($file));
if ( $pos = strpos($theme, '/') )
   $theme = substr($theme, 0, $pos);

(Since /themes/ is hard-coded)

I'm really open to suggestions on a better way there..

Patch is now stale.

Implementation wanted for 2.8, or future?

Adding this in 2.8 would be really valuable.

moving to Future pending a patch

in 3.0.1 still there is no hhok for the theme activate event

@christian_gnoth

The Version number is the WP version for which the issue was first reported, and it must not be changed.

More and more Theme's are taking the idea that the function file is virtually the same as a plugin to heart and adding options... Options which can not be removed easily by users since there is no uninstall support for themes as there is with plugins. This leads to a build up of useless data.

I'm of the opinion that Theme's are mature enough at this point to gain this functionality that plugins already have.

Anyone interested in a fresh look at this ticket?

As indicated in #14849 I think one option would be to have an autoloaded option to keep track of whether a theme activation hook needs to be fired.

as themes are activated, it should be no problem to call a seperate function for

deactivation and activation

the deactivation function should be called for the old theme and the activation function for the new theme. then through a hook the theme developer can fill that functions with actions.

For the deactivation hook to work, the functions.php of the old theme has to be loaded. I think the most logical time to call it would be just before switching to the new theme.

For the deactivation hook to work, the functions.php of the old theme has to be loaded. I think the most logical time to call it would be just before switching to the new theme.

Current generation themes utilise the 'switch_themes' action, which fires on the processing of the theme-change option. That should be the last "page load" which utilises that theme in its current state.

Related: #14955

I have written a code which provides a reliable activation/deactivation theme hooks. Please check it out and let me know what you guys think!

 http://www.krishnakantsharma.com/2011/01/activationdeactivation-hook-for-wordpress-theme/

Note: Though this can be used in core and it will work well with themes, I think if we are modifying core then we can place a more direct code, instead of this indirect patch.

So, we alredy had a theme deactivation hook and now we have theme activation hook as well, since [18656]:

Theme activation hook: 'after_switch_theme'

Theme de-activation hook: 'switch_theme'

It's a little backwards from a theme author's perspective, but it works.

Reopening. See comment 86 in #17979.

Guess we don't actually have an API for this currently.