Source code for ferris.core.events

"""
Global Ferris events.
Applications may also fire events with this bus
"""

from event import NamedEvents

# The Global Events Bus
# This is just a NamedEvents object that certain parts of ferris tap into
# to notify the application or other ferris components about changes.
# See individual components for events.
#
# Exercise caution with threadsafety and events. You should register all
# events and listeners on application startup.
global_events = NamedEvents()


def fire(event_name, *args, **kwargs):
    """
    Calls all of the registered event handlers for a given event. Passes through all arguments
    """
    return global_events[event_name](*args, **kwargs)


def on(event_name):
    """
    Automatically called when the specified event occurs.
    """
    def inner(f):
        global_events[event_name] += f
    return inner


def register(event_or_list):
    if not isinstance(event_or_list, list):
        event_or_list = [event_or_list]
    for event in event_or_list:
        global_events.getEvent(event)

# Pre-register some events
register([
    'before_template_render',
    'after_template_render'
])