[tg-trunk] Proposal: Events

[Jeff Watkins]

There's a pending ticket for having identity fire events based on what's happening. I'd like to implement this (at some point), but I think having a generic event system is really powerful. I propose the following: # Preliminary events system from turbogears.decorator import decorator _event_registry= dict(); def register_event_hook( event_name, hook_fn ):     '''     Add the hook function to the list of event hooks.     '''     if not event_name in _event_registry:         _event_registry[event_name]= []     _event_registry[event_name].append( hook_fn )     def unregister_event_hook( event_name, hook_fn ):     '''     Remove a hook function from the event.     '''     if not event_name in _event_registry:         return        try:         _event_registry[event_name].remove( hook_fn )     except ValueError:         pass def fire_event( event_name, *args, **kwargs ):     if event_name is None:         return     events= _event_registry[event_name]     if not events:         return     for event_fn in events:         event_fn( *args, **kwargs ) def fires_event(event_name, pre_event_name=None):     '''     Function decorator that triggers a hookable event.     '''     def entangle(fn):                 def fires_event(func, self, *args, **kwargs):             fire_event( pre_event_name, *args, **kwargs )             result= fn(self, *args, **kwargs)             fire_event( event_name, *args, **kwargs )             return result                  # Setup events in registry         if not event_name in _event_registry:             _event_registry[event_name]= []         if not pre_event_name in _event_registry:             _event_registry[pre_event_name]= []                         return decorator(fires_event)(fn)     return entangle This would allow me to write the following code: @fires_event( 'identity.validate' ) def validate_identity( self, some, args ): ... And whenever the validate_identity method is invoked, the pre- and post-event handlers get called. Furthermore, if we were to allow cancelling an event, this would allow someone to write a plug-in that tracked the number of times a particular visitor has attempted to log in and lock the account if too many failures have occurred. And other wacky stuff. Any thoughts? -- Jeff Watkins http://newburyportion.com/ "Not everything that can be counted counts, and not everything that counts can be counted." -- Albert Einstein --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TurboGears Trunk" group. To post to this group, send email to turbogears-trunk@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/turbogears-trunk -~----------~----~----~----~------~----~------~--~---