/b-gtk/fix-viz

# Copyright (C) 2011 by Guillaume Hain (zedtux) <zedtux@zedroot.org>

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import Queue

import urllib

import urllib2

import hashlib

import threading

class AvatarProvider(object):

    """Base class for Avatar providers.

    All AvatarProviderXxxx classes should inherite from this one

    and override at least get_base_url.

    """

    def __init__(self, size=80):

        """ Constructor """

        self.size = size

    def get_base_url(self):

        """Return the base URL of this provider.

        """

        raise NotImplementedError(self.get_base_url)

class AvatarDownloaderWorker(threading.Thread):

    """Threaded worker to retrieve avatar from a provider.

    This creates a persistant connection to the provider in order

    to get avatars quickly through the same socket (urllib2).

    """

    def __init__(self, provider_method):

        """Constructor

        :param provider_method: Provider method that returns fields

                 to send with the request.

        """

        threading.Thread.__init__(self)

        self.__stop = threading.Event()

        self.__queue = Queue.Queue()

        self.__provider_method = provider_method

        self.__callback_method = None

        self.__error_method = None

    def stop(self):

        """ Stop this worker """

        self.__stop.set()

        while self.__queue.qsize() > 0:

            self.__queue.get_nowait()

            self.__queue.task_done()

        self.__queue.join()

    @property

    def is_running(self):

        return not self.__stop.is_set()

    def set_callback_method(self, method):

        """Fire the given callback method when treatment is finished."""

        self.__callback_method = method

    def set_error_method(self, method):

        """Fire the given callback when retrieving a avatar fails."""

        self.__error_method = method

    def queue(self, id_field):

        """Put in Queue the id_field to treat in the thread.

        This id_field is for example with Gravatar the email address.

        """

        if self.is_running:

            self.__queue.put(id_field)

            if not self.is_alive():

                self.start()

    def run(self):

        """Worker core code. """

        while self.is_running:

            try:

                id_field = self.__queue.get_nowait()

                # Call provider method to get fields to pass in the request

                url = self.__provider_method(id_field)

                # Execute the request

                try:

                    response = urllib2.urlopen(url)

                except urllib2.URLError, e:

                    if self.__error_method is not None:

                        self.__error_method(e)

                else:

                    # Fire the callback method

                    if not self.__callback_method is None:

                        self.__callback_method(response, id_field)

                self.__queue.task_done()

            except Queue.Empty:

                # There is no more work to do.

                pass

class AvatarProviderGravatar(AvatarProvider):

    """Gravatar provider."""

    def get_base_url(self):

        return "http://www.gravatar.com/avatar.php?"

    def gravatar_id_for_email(self, email):

        """Return a gravatar URL for an email address.."""

        return self.get_base_url() + \

                urllib.urlencode({

                    'gravatar_id': hashlib.md5(email.lower()).hexdigest(),

                    'size': str(self.size)

                })