mediagoblin/mediagoblin/decorators.py

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from functools import wraps

from urlparse import urljoin
from urllib import urlencode

from webob import exc

from mediagoblin.db.util import ObjectId, InvalidId
from mediagoblin.tools.response import redirect, render_404


def require_active_login(controller):
    """
    Require an active login from the user.
    """
    @wraps(controller)
    def new_controller_func(request, *args, **kwargs):
        if request.user and \
                request.user.get('status') == u'needs_email_verification':
            return redirect(
                request, 'mediagoblin.user_pages.user_home',
                user=request.user.username)
        elif not request.user or request.user.get('status') != u'active':
            next_url = urljoin(
                    request.urlgen('mediagoblin.auth.login',
                        qualified=True),
                    request.url)

            return exc.HTTPFound(
                location='?'.join([
                    request.urlgen('mediagoblin.auth.login'),
                    urlencode({
                        'next': next_url})]))

        return controller(request, *args, **kwargs)

    return new_controller_func


def user_may_delete_media(controller):
    """
    Require user ownership of the MediaEntry to delete.
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        uploader_id = request.db.MediaEntry.find_one(
            {'_id': ObjectId(request.matchdict['media'])}).uploader
        if not (request.user.is_admin or
                request.user._id == uploader_id):
            return exc.HTTPForbidden()

        return controller(request, *args, **kwargs)

    return wrapper


def user_may_alter_collection(controller):
    """
    Require user ownership of the Collection to modify.
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        creator_id = request.db.User.find_one(
            {'username': request.matchdict['user']}).id
        if not (request.user.is_admin or
                request.user._id == creator_id):
            return exc.HTTPForbidden()

        return controller(request, *args, **kwargs)

    return wrapper


def uses_pagination(controller):
    """
    Check request GET 'page' key for wrong values
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        try:
            page = int(request.GET.get('page', 1))
            if page < 0:
                return render_404(request)
        except ValueError:
            return render_404(request)

        return controller(request, page=page, *args, **kwargs)

    return wrapper


def get_user_media_entry(controller):
    """
    Pass in a MediaEntry based off of a url component
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        user = request.db.User.find_one(
            {'username': request.matchdict['user']})

        if not user:
            return render_404(request)
        media = request.db.MediaEntry.find_one(
            {'slug': request.matchdict['media'],
             'state': u'processed',
             'uploader': user._id})

        # no media via slug?  Grab it via ObjectId
        if not media:
            try:
                media = request.db.MediaEntry.find_one(
                    {'_id': ObjectId(request.matchdict['media']),
                     'state': u'processed',
                     'uploader': user._id})
            except InvalidId:
                return render_404(request)

            # Still no media?  Okay, 404.
            if not media:
                return render_404(request)

        return controller(request, media=media, *args, **kwargs)

    return wrapper


def get_user_collection(controller):
    """
    Pass in a Collection based off of a url component
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        user = request.db.User.find_one(
            {'username': request.matchdict['user']})

        if not user:
            return render_404(request)

        collection = request.db.Collection.find_one(
            {'slug': request.matchdict['collection'],
             'creator': user._id})

        # Still no collection?  Okay, 404.
        if not collection:
            return render_404(request)

        return controller(request, collection=collection, *args, **kwargs)

    return wrapper


def get_user_collection_item(controller):
    """
    Pass in a CollectionItem based off of a url component
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        user = request.db.User.find_one(
            {'username': request.matchdict['user']})

        if not user:
            return render_404(request)

        collection = request.db.Collection.find_one(
            {'slug': request.matchdict['collection'],
             'creator': user._id})

        collection_item = request.db.CollectionItem.find_one(
            {'_id': request.matchdict['collection_item'] })

        # Still no collection item?  Okay, 404.
        if not collection_item:
            return render_404(request)

        return controller(request, collection_item=collection_item, *args, **kwargs)

    return wrapper


def get_media_entry_by_id(controller):
    """
    Pass in a MediaEntry based off of a url component
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        try:
            media = request.db.MediaEntry.find_one(
                {'_id': ObjectId(request.matchdict['media']),
                 'state': u'processed'})
        except InvalidId:
            return render_404(request)

        # Still no media?  Okay, 404.
        if not media:
            return render_404(request)

        return controller(request, media=media, *args, **kwargs)

    return wrapper