path: root/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 werkzeug.exceptions import Forbidden, NotFound
from oauthlib.oauth1 import ResourceEndpoint

from mediagoblin import mg_globals as mgg
from mediagoblin import messages
from mediagoblin.db.models import MediaEntry, User
from mediagoblin.tools.response import json_response, redirect, render_404
from mediagoblin.tools.translate import pass_to_ugettext as _

from mediagoblin.federation.tools.request import decode_authorization_header
from mediagoblin.federation.oauth import GMGRequestValidator

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.status == u'needs_email_verification':
            return redirect(
                request, 'mediagoblin.user_pages.user_home',
                user=request.user.username)
        elif not request.user or request.user.status != u'active':
            next_url = urljoin(
                    request.urlgen('mediagoblin.auth.login',
                        qualified=True),
                    request.url)

            return redirect(request, 'mediagoblin.auth.login',
                            next=next_url)

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

    return new_controller_func

def active_user_from_url(controller):
    """Retrieve User() from <user> URL pattern and pass in as url_user=...

    Returns a 404 if no such active user has been found"""
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        user = User.query.filter_by(username=request.matchdict['user']).first()
        if user is None:
            return render_404(request)

        return controller(request, *args, url_user=user, **kwargs)

    return wrapper


def user_may_delete_media(controller):
    """
    Require user ownership of the MediaEntry to delete.
    """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        uploader_id = kwargs['media'].uploader
        if not (request.user.is_admin or
                request.user.id == uploader_id):
            raise Forbidden()

        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.query.filter_by(
            username=request.matchdict['user']).first().id
        if not (request.user.is_admin or
                request.user.id == creator_id):
            raise Forbidden()

        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 = User.query.filter_by(username=request.matchdict['user']).first()
        if not user:
            raise NotFound()

        media = None

        # might not be a slug, might be an id, but whatever
        media_slug = request.matchdict['media']

        # if it starts with id: it actually isn't a slug, it's an id.
        if media_slug.startswith(u'id:'):
            try:
                media = MediaEntry.query.filter_by(
                    id=int(media_slug[3:]),
                    state=u'processed',
                    uploader=user.id).first()
            except ValueError:
                raise NotFound()
        else:
            # no magical id: stuff?  It's a slug!
            media = MediaEntry.query.filter_by(
                slug=media_slug,
                state=u'processed',
                uploader=user.id).first()

        if not media:
            # Didn't find anything?  Okay, 404.
            raise NotFound()

        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.query.filter_by(
            username=request.matchdict['user']).first()

        if not user:
            return render_404(request)

        collection = request.db.Collection.query.filter_by(
            slug=request.matchdict['collection'],
            creator=user.id).first()

        # 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.query.filter_by(
            username=request.matchdict['user']).first()

        if not user:
            return render_404(request)

        collection_item = request.db.CollectionItem.query.filter_by(
            id=request.matchdict['collection_item']).first()

        # 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):
        media = MediaEntry.query.filter_by(
                id=request.matchdict['media_id'],
                state=u'processed').first()
        # Still no media?  Okay, 404.
        if not media:
            return render_404(request)

        given_username = request.matchdict.get('user')
        if given_username and (given_username != media.get_uploader.username):
            return render_404(request)

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

    return wrapper


def get_workbench(func):
    """Decorator, passing in a workbench as kwarg which is cleaned up afterwards"""

    @wraps(func)
    def new_func(*args, **kwargs):
        with mgg.workbench_manager.create() as workbench:
            return func(*args, workbench=workbench, **kwargs)

    return new_func


def allow_registration(controller):
    """ Decorator for if registration is enabled"""
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        if not mgg.app_config["allow_registration"]:
            messages.add_message(
                request,
                messages.WARNING,
                _('Sorry, registration is disabled on this instance.'))
            return redirect(request, "index")

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

    return wrapper


def auth_enabled(controller):
    """Decorator for if an auth plugin is enabled"""
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        if not mgg.app.auth:
            messages.add_message(
                request,
                messages.WARNING,
                _('Sorry, authentication is disabled on this instance.'))
            return redirect(request, 'index')

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

    return wrapper

def oauth_required(controller):
    """ Used to wrap API endpoints where oauth is required """
    @wraps(controller)
    def wrapper(request, *args, **kwargs):
        data = request.headers
        authorization = decode_authorization_header(data)

        if authorization == dict():
            error = "Missing required parameter."
            return json_response({"error": error}, status=400)

         
        request_validator = GMGRequestValidator()
        resource_endpoint = ResourceEndpoint(request_validator)
        valid, request = resource_endpoint.validate_protected_resource_request(
                uri=request.url,
                http_method=request.method,
                body=request.get_data(),
                headers=dict(request.headers),
                )

        if not valid:
            error = "Invalid oauth prarameter."
            return json_response({"error": error}, status=400)

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

    return wrapper