Creating and subscribing to events in Zope

Creating your event

• An event is just an interface definition and the event object declaration
  

  import zope.component.interfaces
  from zope.interface import implements
  
  class IMyNewEvent(zope.component.interfaces.IObjectEvent):
      """An object has been modified"""
  
  class MyNewEvent(zope.component.interfaces.ObjectEvent):
      """An object has been modified"""
      implements(IMyNewEvent)
  

• The real magic happens when fire off the event
  

  from zope.event import notify
  
  notify(MyNewEvent(context))

• Now to subscribe to the event do something like this,
  

  <subscriber
    for="myproduct.myobject
         myproduct.interfaces.IMyNewEvent"
    handler=".subscribers.event_handler"
    />

• Now in a file subscribers.py add the method event_handler like this,
  

  def event_handler(obj, event):
    # do something interesting here...
    pass