# Hooks

The hook subsystem provides a simple, passive interface to ApisCP without module extensions. Hooks come in two flavors, account and API. Account hooks are available for edit, create, delete, suspend, activate, import, and export operations. Unlike a module, a hook cannot interrupt flow.

# Account hooks

# Installation

Example hooks are provided in bin/hooks as part of the apnscp distribution. Active hooks are located in config/custom/hooks. All hooks follow a familiar interface, with the first argument the site identifier. Import and export hooks also include the target format as well as source/destination file respectively.

A hook is accepted if it has a ".php" or ".sh" extension. Any other matching hook is ignored.

cd /usr/local/apnscp
mkdir -p config/custom/hooks
cp bin/hooks/editDomain.php config/custom/hooks
# Create the domain
env DEBUG=1 VERBOSE=-1 AddDomain -c siteinfo,domain=hooktest.com -c siteinfo,admin_user=hooktest -c dns,enabled=0

env DEBUG=1 enables opportunistic debugging, which generates additional information at runtime. VERBOSE=-1 is a shorthand flag to enable backtraces for all levels of error reporting. Backtraces help identify the pathway a problem bubbles up. Refer to sample code in each hook for context strategies.

# API hooks

Programming is covered in detail in PROGRAMMING.md. Hooks are simplified means of reacting to an API call in ApisCP. Unlike a surrogate, which extends a module's internals, an API hook is decoupled from implementation details and may only react to the return value (and arguments) of an API call. A hook cannot interrupt an API call nor is it always called for each invocation. A hook is called within the module context and thus has access to all private and protected properties and methods of the module class to which it binds therefore it must not be declared with the static modifier.


Hooks are only called if the method is the first call of the module API. For tighter control, a surrogate is preferred, which is always called when the corresponding method is called.

API hooks are declared in config/custom/boot.php as with other overrides. Hooks are intended to initialize early in the request lifecycle. Once a module is invoked, associated callbacks are frozen.

API hooks are only called if the method is the first call of the module API. For tighter control, a surrogate is preferred, which is always called when the corresponding method is called.

    \a23r::registerCallback('common', 'whoami', function ($ret, $args) {
		info("whoami called with arguments: [%s] + %d permission level", implode(', ', $args), $this->permission_level);

Sample output

Running cpcmd common:whoami would report the following,

INFO    : whoami called with arguments: [] + 8 permission level
Reporter level: OK
INFO: whoami called with arguments: [] + 8 permission level

Hooks cannot interrupt flow, but can enhance it. Consider installing WordPress and bundling additional plugins at install. This would fire after WordPress has successfully installed. The following example would add Yoast SEO + WP Smushit plugins and install Hello Elementor theme using the ApisCP API.

    \a23r::registerCallback('wordpress', 'install', function ($ret, $args) {
        if (!$ret) {
        // get arguments to wordpress:install
        [$hostname, $path, $opts] = $args;
        foreach (['wordpress-seo', 'wp-smushit'] as $plugin) {
            $this->wordpress_install_plugin($hostname, $path, $plugin);
        // install and activate Hello Elementor theme
        $this->wordpress_install_theme($hostname, $path, 'hello-elementor');

Likewise consider the call graph for wordpress:install:

wordpress:install hook call graph

Methods in green will be checked for callback functionality. Methods in red will not. Callbacks only work on the entry point of the module. A cross-module call (calling another method in another module) creates an entry point in a new module. An in-module call conversely does not leave the module and will not trigger a callback. Any method could be called independently and it would trigger a callback.

If greater fidelity is required, consider converting the callbacks into a surrogate. The above example may be rewritten in surrogate form as:

    class Wordpress_Module_Surrogate extends Wordpress_Module
    	public function install(string $hostname, string $path = '', array $opts = array()): bool 
            if (!parent::install($hostname, $path, $opts)) {
                return false;
            foreach(['wordpress-seo', 'wp-smushit'] as $plugin) {
                $this->install_plugin($hostname, $path, $plugin);
            $this->install_theme($hostname, $path, 'hello-elementor');
            return true;