~azzar1/unity/add-show-desktop-key

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# IVLE - Informatics Virtual Learning Environment
# Copyright (C) 2009 The University of Melbourne
#
# 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Author: William Grant

'''Media file support for the framework.'''

import os
import inspect
import mimetypes

import ivle.conf
from ivle.webapp.base.views import BaseView
from ivle.webapp.base.plugins import ViewPlugin
from ivle.webapp.errors import NotFound

def media_url(req, plugin, path):
    '''Generates a URL to a media file.
    
    Plugin can be a string, in which case it is put into the path literally,
    or a plugin object, in which case its name is looked up.'''
    if not isinstance(plugin, basestring):
        plugin = req.reverse_plugins[plugin]
        
    return os.path.join(ivle.conf.root_dir, '+media', plugin, path)

class MediaFileView(BaseView):
    '''A view for media files.

    This serves static files from directories registered by plugins.

    Plugins wishing to export media should declare a 'media' attribute,
    pointing to the directory to serve (relative to the module's directory).
    The contents of that directory will then be available under
    /+media/python.path.to.module.
    '''
    def __init__(self, req, ns, path):
        self.ns = ns
        self.path = path

    def _make_filename(self, req):
        try:
            plugin = req.plugins[self.ns]
        except KeyError:
            raise NotFound()

        try:
            mediadir = plugin.media
        except AttributeError:
            raise NotFound()

        plugindir = os.path.dirname(inspect.getmodule(plugin).__file__)

        return os.path.join(plugindir, mediadir, self.path)

    def render(self, req):
        # If it begins with ".." or separator, it's illegal. Die.
        if self.path.startswith("..") or self.path.startswith('/'):
            raise Forbidden()

        filename = self._make_filename(req)

        # Find an appropriate MIME type.
        (type, _) = mimetypes.guess_type(filename)
        if type is None:
            type = 'application/octet-stream'

        # Get out if it is unreadable or a directory.
        if not os.access(filename, os.F_OK):
            raise NotFound()
        if not os.access(filename, os.R_OK) or os.path.isdir(filename):
            raise Forbidden()

        req.content_type = type
        req.sendfile(filename)

class Plugin(ViewPlugin):
    urls = [
        ('+media/:ns/*path', MediaFileView),
    ]