This page is work in progress documentation for Civi Rules.
Civi Rules is based on the Drupal Rules module and does react on an event (post create contribution) and executes a certain action when certain conditions are met.
This page will contain what we have thought of what needs to be done to develop such an extension. Rather than just starting (what we have done with trigger-action extension) this one is a bit more thought of. So this description is also a basic for a wider debate on how things should work.
- The action should be basically API actions
- Should be flexible to extend by developers. E.g. it should be easy to add new event types, new condition types, new action types
- Rules (event, condition and condition) should be stored in the database as well as in code, like Drupal Views and Drupal Rules.
- It should be possible to extend the storage layer
- It should use the queue mechanism of CiviCRM Core (take a look at scheduled reminders on how to use this queue mechanism)
- It should be possible to send e-mail, sms, print pdf letter as an action
The following needs to be done. This are the actions we identified so far
Investigate the core queue mechanism and document it
Create the basic framework for the rules extension
Create a UI around the framework
(API) action for sending e-mail
(API) action for sending SMS
(API) action for printing PDF Letter
Below a draft of the API for the framework. This api consist of hooks and functions other extensions could invoke.
- hook_civicrm_rules_event_types: returns event types to the framework
- Invoke Event: api to invoke an event in the civicrm rules module
- hook_civicrm_rules_condition_types: returns condition types to the framework
- hook_civicrm_rules_action_types: return action types to the frameworks
- hook_civicrm_rules_storage: returns a storage mechanism for rules. A storage mechanism is used to store the rule for example in the database, or in php array, or in json or in whatever format
Below a more detailed description of the interfaces we are going to use in the framework. The interfaces we have identified are:
- Storage layer
- event definition
- condition definition
- action definition
Below a more detailed description of the hooks
The API of this extension consist of a call to the extension to trigger events of a certain type. E.g. in the post hook we want trigger the post event for a certain object.
This call will invoke the rules extension to check whether any post events should be checked. Our aim is to implement by default the pre and the post events which are triggered in the pre and post hook and we will use a flexible mechanism because if any new use cases appear in the feature they can be easily implemented. However we cannot think of any yet.
As soon as invoke event is fired the rules module will check whether any active events are available and executes those events.
The invoke event has the following parameters:
- event: the name of the event
- event_parameters: an array with additional parameters for this specific event