Hooks and WebHooks

Elefant's controller implements a simple hook mechanism for triggering other handlers from within one handler when a particular event or action has occurred. Similar to the idea of WebHooks, this provides a means of triggering handlers from within each other without hard-coding the specific handlers in the trigger, so that you can modify them independent of the original code.

Hooks are particularly useful when one or more actions depend on another, for example keeping a search index of your site up-to-date, or auto-posting to Twitter or other sources when you make a new blog post.

There are three components to hooks in Elefant:

The [Hooks] section in conf/config.php
The handler that triggers the hooks
The handlers that respond to the hook event

Configuration

Hooks can be named anything you want, but it is good practice to name them after the handler that triggers them so you can easily look them up, although it is possible to trigger the same hook from multiple handlers. Here's how a hook looks in conf/config.php:

admin/add[] = search/add

This says that the search/add handler should respond when the admin/add hook is triggered. You can also specify multiple handlers to the same hook like this:

admin/add[] = search/add
admin/add[] = anotherapp/add

Triggering a hook on an event

Triggering a hook takes only one line of code:

<?php

$this->hook ('admin/delete', array ('page' => $id));

?>

The first parameter is the hook name, and the second is an associative array of data that will be passed to the responding handlers.

Responding to an event

There are several things to consider in hook response handlers:

Do we need to limit access to this handler?
Verifying data values
Accessing the hook event data

If we need to restrict access and make sure that only another request inside Elefant is accessing the response handler, we can check the $this->internal value:

<?php

if (! $this->internal) {
  die ('Must be called by another handler');
}

?>

As for verifying data values, we can use the Forms and input validation features for that.

Finally, you can access data passed to your handler through the $this->data array, e.g., $this->data['page'] for the data from the example above.

List of built-in hooks

Here is a list of hooks that are built into the default Elefant installation:

admin/add
admin/edit
admin/delete
blocks/add
blocks/edit
blocks/delete
blog/add
blog/edit
blog/delete
user/add
user/edit
user/delete

WebHooks

Being a WebHooks consumer in Elefant is easy: Simply create a handler for it and give that handler's URL to the third party site.

In creating a WebHook for consumption by other services, it's a good idea to wrap it in an ordinary Elefant hook so you can abstract it from the original code just like ordinary hooks. Then it's simply a matter of issuing a POST request to the third party service, either via http_post_fields(), cURL, or file_put_contents() with an HTTP POST stream. For example:

<?php

$res = http_post_fields (
  'http://some.service.com/webhooks/consumer',
  $this->data
);

?>

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This documentation was generated by the Elefant Documentation Project. We're always open to new contributions *wink* *wink*

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