view MoinMoin/events/__init__.py @ 2638:6e84127a1860

Finally all known bugs fixed, OOB is used to send links with jabber. More... Changed the way notifications are called. Notification data is now stored in dicts, instead of separate arguments. This helps extensibility if more extensions like OOB Data are to be added in the future. Also fixed some previously missed bugs.
author Karol 'grzywacz' Nowak <grzywacz@sul.uni.lodz.pl>
date Sun, 05 Aug 2007 22:46:04 +0200
parents f42fb1ae0a38
children c6e39279f83b
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# -*- coding: iso-8859-1 -*-
"""
    MoinMoin - event (notification) framework

    This code abstracts event handling in MoinMoin,
    currently for notifications. It implements the observer pattern.

    @copyright: 2007 by Karol Nowak <grywacz@gmail.com>
    @license: GNU GPL, see COPYING for details.
"""

import logging

from MoinMoin import wikiutil
from MoinMoin.util import pysupport
from MoinMoin.wikiutil import PluginAttributeError

# Create a list of extension actions from the package directory
modules = pysupport.getPackageModules(__file__)

# A module-wide Logger, don't use it from outside
logger = logging.getLogger("events")
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler())

# Dummy pseudo-getText function used in event descriptions,
# so that they get into .po files
_ = lambda x: x


class Event(object):
    """A class handling information common to all events."""

    # NOTE: each Event subclass must have a unique name attribute
    name = u"Event"

    def __init__(self, request):
        self.request = request


class PageEvent(Event):
    """An event related to a page change"""

    name = u"PageEvent"

    def __init__(self, request):
        Event.__init__(self, request)


class PageChangedEvent(PageEvent):

    name = u"PageChangedEvent"
    description = _(u"""Page has been modified""")
    req_superuser = False

    def __init__(self, request, page, comment):
        PageEvent.__init__(self, request)
        self.page = page
        self.comment = comment


class TrivialPageChangedEvent(PageEvent):

    name = u"TrivialPageChangedEvent"
    description = _(u"Page has been modified in a trivial fashion")
    req_superuser = False

    def __init__(self, request, page, comment):
        PageEvent.__init__(self, request)
        self.page = page
        self.comment = comment


class PageRenamedEvent(PageEvent):

    name = u"PageRenamedEvent"
    description = _(u"""Page has been renamed""")
    req_superuser = False

    def __init__(self, request, page, old_page, comment=""):
        PageEvent.__init__(self, request)
        self.page = page
        self.old_page = old_page
        self.comment = comment


class PageDeletedEvent(PageEvent):

    name = u"PageDeletedEvent"
    description = _(u"""Page has been deleted""")
    req_superuser = False

    def __init__(self, request, page, comment):
        PageEvent.__init__(self, request)
        self.page = page
        self.comment = comment


class PageCopiedEvent(PageEvent):

    name = u"PageCopiedEvent"
    description = _(u"""Page has been copied""")
    req_superuser = False

    def __init__(self, request, page, old_page, comment):
        PageEvent.__init__(self, request)
        self.page = page
        self.old_page = old_page
        self.comment = comment


class FileAttachedEvent(PageEvent):

    name = u"FileAttachedEvent"
    description = _(u"""A new attachment has been added""")
    req_superuser = False

    def __init__(self, request, pagename, filename, size):
        PageEvent.__init__(self, request)
        self.request = request
        self.pagename = pagename
        self.filename = filename
        self.size = size


class PageRevertedEvent(PageEvent):

    name = u"PageRevertedEvent"
    description = _(u"""A page has been reverted to a previous state""")
    req_superuser = False

    def __init__(self, request, pagename, previous, current):
        PageEvent.__init__(self, request)
        self.pagename = pagename
        self.previous = previous
        self.current = current


class SubscribedToPageEvent(PageEvent):

    name = u"SubscribedToPageEvent"
    description = _(u"""A user has subscribed to a page""")
    req_superuser = True

    def __init__(self, request, pagename, username):
        PageEvent.__init__(self, request)
        self.pagename = pagename
        self.username = username


class JabberIDSetEvent(Event):
    """ Sent when user changes her Jabber ID """

    def __init__(self, request, jid):
        Event.__init__(self, request)
        self.jid = jid

class JabberIDUnsetEvent(Event):
    """ Sent when Jabber ID is no longer used

    Obviously this will be usually sent along with JabberIDSetEvent,
    because we require user's jabber id to be unique by default.

    """
    def __init__(self, request, jid):
        Event.__init__(self, request)
        self.jid = jid

class UserCreatedEvent(Event):
    """ Sent when a new user has been created """

    name = u"UserCreatedEvent"
    description = _(u"""A new account has been created""")
    req_superuser = True

    def __init__(self, request, user):
        Event.__init__(self, request)
        self.user = user

class PagePreSaveEvent(Event):
    """ Event sent when a page is about to be saved

    This can be used to abort a save, for instance,
    if handler returns

    """

    name = u"PagePreSaveEvent"

    def __init__(self, request, page_editor, new_text):
        Event.__init__(self, request)
        self.page_editor = page_editor
        self.new_text = new_text


class EventResult:
    """ This is a base class for messages passed from event handlers """
    pass

class Abort(EventResult):
    """ Result returned if handler wants to abort operation that sent the event """
    def __init__(self, reason):
        """
        @param reason: human-readable reason of failure
        """
        self.reason = reason


def get_handlers(cfg):
    """Create a list of available event handlers.

    Each handler is a handle() function defined in an plugin,
    pretty much like in case of actions.

    TODO: maybe make it less dumb? ;-)

    """
    event_handlers = []
    names = wikiutil.getPlugins("events", cfg)

    for name in names:
        try:
            handler = wikiutil.importPlugin(cfg, "events", name, "handle")
        except PluginAttributeError:
            handler = None

        if handler is not None:
            event_handlers.append(handler)

    return event_handlers


def send_event(event):
    """Function called from outside to process an event

    @return: a list of messages returned by handlers
    @rtype: list
    """

    # A list of messages generated by event handlers, passed back to caller
    msg = []
    cfg = event.request.cfg

    # Try to handle the event with each available handler (for now)
    for handle in cfg.event_handlers:
        retval = handle(event)

        assert retval is None or isinstance(retval, EventResult)

        if retval:
            msg.append(retval)

    return msg

def get_subscribable_events():
    """Create and return a list of user-visible events

    @return: A list of user-visible events described by dictionaries
    @rtype: dict
    """
    defs = globals()
    subscribable_events = {}

    for ev in defs.values():
        if type(ev) is type and issubclass(ev, Event) and ev.__dict__.has_key("description") and ev.__dict__.has_key("name"):
            subscribable_events[ev.name] = {'desc': ev.description, 'superuser': ev.req_superuser}

    return subscribable_events

# Get rid of the dummy getText so that it doesn't get imported with *
del _