After the solution to this question was to get a function to launch BEFORE the init
action is fired by taking the sequence out of its function, it got me thinking, is there any earlier in the WP load sequence that I can hook a function into?
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I really wish they would have added a plugin call before the whole system was loaded.– XeoncrossJan 22, 2012 at 4:00
3 Answers
muplugins_loaded
is the earliest hook.
Depending on your wordpress setup, you may not have any plugins in the
MU_PLUGINS
directory. In that case this hook may not fire.
The next best hook to trigger is plugins_loaded
.
RESOURCES
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9Yep, but note that it runs before loading of normal plugins and theme so it is somewhat useless in practice.
plugins_loaded
andafter_setup_theme
are earliest appropriate for normal plugins and theme accordingly.– RarstJul 21, 2011 at 11:09 -
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2This answer contains some very bad information. The
muplugins_loaded
action is not conditional on anything . It will fire. If there are no mu-plugins, though, I am not sure how you'd get code to run before early enough to use the hook.– s_ha_dumJan 10, 2016 at 15:08
For anyone interested in finding this out on your own, there is an awesome plugin named Query Monitor.
Install and activate the plugin (on staging or dev install obviously) and just select what you want from the drop down.
As mentioned in a comment on the accepted answer, the hook muplugins_loaded is not conditional. If you read the source code you will find that it is always fired - at least in recent versions of WordPress. According to the documentation it is also the first available hook. However, unless you are actually writing a must-use or network activated plugin it doesn't make much sense to use it since it will fire before your plugin or theme is loaded.
If you are writing a plugin, then the plugins_loaded is the first general action hook to use.
If you are adding code to your theme's functions.php, then you could use after_setup_theme.