Source code for assembl.lib.discussion_creation

"""
A plugin api for processes that will be run when a discussion is created
"""
from __future__ import print_function

from builtins import object
from zope import interface
from pyramid.path import DottedNameResolver
from pyramid.config import aslist

resolver = DottedNameResolver(__package__)


class IDiscussionCreationCallback(interface.Interface):
    """defines a plugin that will called when a discussion is created.

    Each callback must be idempotent: Calling it once or several times
    should produce the same result."""
    def discussionCreated(self, discussion):
        """called when a discussion is created.
        No return value, may raise exceptions.
        Exceptions should make the transaction fail, and the discussion
        will not be created.
        """
        pass


@interface.implementer(IDiscussionCreationCallback)
class DiscussionCreationPrinter(object):
    """A dummy :py:class:`IDiscussionCreationCallback` for testing purposes"""

    def discussionCreated(self, discussion):
        print("discussionCreated", discussion)


def setup_discussion_callbacks(registry):
    """Register all :py:class:`IDiscussionCreationCallback` implementations
    according to ``local.ini``"""
    settings = registry.settings
    class_names = aslist(settings.get('discussion_callbacks', ''))
    for class_name in class_names:
        cls = resolver.resolve(class_name)
        registry.registerUtility(
            cls(), IDiscussionCreationCallback, cls.__name__)


def includeme(config):
    setup_discussion_callbacks(config.registry)