The WordPress Core drop-in file
sunrise.php loads loads very early in the WordPress loading sequence, before
mu-plugins, any active plugins, and the active theme. Because of this, what can be done in
sunrise.php is limited, and largely confined to executing pure PHP to set constants that override WordPress Core behavior.
In order to load additional code to
sunrise.php on VIP, create a
client-sunrise.php file in a site’s repository in the root
vip-config directory. If a
client-sunrise.php file exists in the
vip-config directory, it will be loaded automatically.
Guidelines for use
Coded added to
- be used only when early execution is absolutely required (e.g. for performance reasons or to override aspects of the request very early on). Code that can run later in execution should typically be written in the plugin or theme context and leverage the WordPress Plugin API.
- be written with (as much as possible) pure PHP.
- not require database access or access to any persistent data, but often makes decisions or performs actions based on intrinsic characteristics of the request, such as the domain or URI. Because it executes on every single request handled by WordPress, make sure that use of
sunrise.phpdoes not introduce the kinds of performance penalties associated with queries or other expensive operations.
- be limited to specific conditions under which the code executes. Code executed within
sunrise.phpcan have far-reaching effects, so reducing the probability of unintended side-effects is recommended (e.g. limiting it to only certain URLs or certain domains).
Configuration for local development
If the VIP Local Development Environment is being used for local development, no special configuration is necessary; a
client-sunrise.php file will load automatically if it is present in an application’s codebase.
For all other local development applications, the following steps will be necessary for
client-sunrise.php to load as expected:
- Copy or symlink
- Copy or symlink
Last updated: August 29, 2023