Test if content creation with AI could stimulate the creation of reviewed content

docs/backend/subscribers.md

@@ -11,8 +11,92 @@ myst:
 
 # Subscribers (event handlers)
 
-```{todo}
-Move content from:
--   https://5.docs.plone.org/external/plone.app.dexterity/docs/advanced/event-handlers.html
--   https://5.docs.plone.org/develop/addons/components/events.html
+In Plone 6, the event system provides a robust mechanism for developers to execute custom actions in response to various occurrences within the system.
+This capability is facilitated through the use of event subscribers, also known as event handlers, which listen for specific events and perform predefined operations when those events are triggered.
+
+## Overview of the Event System
+
+Plone's event system is built upon the Zope Component Architecture's `zope.event` package, enabling a publish-subscribe pattern where events are broadcasted, and subscribers (event handlers) respond accordingly.
+Key characteristics of this system include:
+
+- **Simplicity**: The event system is straightforward to implement and use.
+- **Non-deterministic Handler Execution Order**: The order in which event handlers are invoked is not specified and cannot be controlled.
+- **Non-cancelable Events**: Once an event is emitted, all associated handlers will receive it; events cannot be canceled.
+- **No Return Values**: Event handlers do not return values.
+- **Exception Handling**: Exceptions raised within an event handler can interrupt the request processing.
+
+Events are typically defined by interfaces and may carry pertinent information about the event.
+Object events, which pertain to specific content objects, implement the `zope.component.interfaces.IObjectEvent` interface and include an `object` attribute referencing the related content object.
+This structure allows event handlers to be registered for specific object types and event types.
+
+## Commonly Used Event Types
+
+Several standard event types are frequently utilized in Plone:
+
+- **`zope.lifecycleevent.interfaces.IObjectCreatedEvent`**: Triggered just after an object is created but before it is added to its container.
+- **`zope.lifecycleevent.interfaces.IObjectAddedEvent`**: Occurs when an object has been added to its container.
+- **`zope.lifecycleevent.interfaces.IObjectModifiedEvent`**: Fired when an object is modified.
+- **`zope.lifecycleevent.interfaces.IObjectRemovedEvent`**: Triggered when an object is removed from its container.
+
+These events are part of the `zope.lifecycleevent` package and are integral to Plone's event-handling infrastructure.
+
+## Registering Event Handlers
+
+Event handlers can be registered in two primary ways: using ZCML (Zope Configuration Markup Language) or Python decorators.
+
+### Using ZCML
+
+To register an event handler via ZCML, add a `<subscriber>` directive to your package's `configure.zcml` file:
+
+```xml
+<subscriber
+    for=".interfaces.IMyContentTypeClass zope.lifecycleevent.IObjectCreatedEvent"
+    handler=".your_module.your_function"
+/>
+```
+
+In this configuration:
+
+- The `for` attribute specifies the interface of the content type and the event interface.
+- The `handler` attribute points to the function that will handle the event.
+
+This setup ensures that `your_function` is called whenever an object implementing `IMyContentTypeClass` is created.
+
+### Using Python Decorators
+
+Alternatively, you can register an event handler using the `subscribe` decorator from the `zope.component` module:
+
+```python
+from zope.component import adapter
+from zope.lifecycleevent.interfaces import IObjectCreatedEvent
+from .interfaces import IMyContentTypeClass
+
+@adapter(IMyContentTypeClass, IObjectCreatedEvent)
+def your_function(obj, event):
+    # Your code here
+```
+
+In this example, `your_function` will be invoked whenever an object implementing `IMyContentTypeClass` is created.
+
+## Firing Events
+
+To emit an event, use the `notify` function from the `zope.event` module:
+
+```python
+from zope.event import notify
+from zope.lifecycleevent import ObjectModifiedEvent
+
+notify(ObjectModifiedEvent(your_object))
 ```
+
+This call broadcasts an `ObjectModifiedEvent`, and all subscribers to this event will be notified.
+
+## Considerations for Event Handlers
+
+When implementing event handlers, keep the following considerations in mind:
+
+- **Performance**: Since event handlers are executed synchronously, long-running operations can delay the request processing.
+- **Error Handling**: Exceptions in event handlers can disrupt the normal flow of the application. Ensure proper error handling within your handlers.
+- **Asynchronous Processing**: For tasks that require significant processing time, consider using asynchronous processing mechanisms to avoid blocking the main application flow.
+
+By effectively leveraging event subscribers, developers can create responsive and dynamic behaviors in Plone 6, enhancing the functionality and user experience of their applications.