accounts: Add context_processor and middleware.

[xnet] / xnet / accounts / decorators.py

import functools

from django.http import HttpResponseForbidden
from django.shortcuts import get_object_or_404

from .models import XGroup, Membership


def with_group(view_func):
    """Converts a group slug into a XGroup object.

    Example:
    >>> @with_group
    ... def my_view(request, group, *args, **kwargs):
    ...     # group is now a XGroup instance
    """

    @functools.wraps(view_func)
    def wrapped_view_func(request, group_slug, *args, **kwargs):
        group = get_object_or_404(XGroup, short=group_slug)

        request.group = group

        return view_func(request, group, *args, **kwargs)

    return wrapped_view_func


class group_required(object):
    """Force a minimum group membership level.

    Also combines with_group features:
    - fetches the XGroup object,
    - sets request.group
    - sets request.membership

    Usage:

    >>> @group_required(level=Membership.LEVEL_MEMBER)
    ... def my_view(request, group, *args, **kwargs):
    ...     pass
    """

    def __init__(self, level=Membership.LEVEL_MEMBER):
        self.level = level

    def __call__(self, view_func):
        @functools.wraps(view_func)
        def wrapped_view_func(request, group_slug, *args, **kwargs):
            group = get_object_or_404(XGroup, short=group_slug)

            try:
                membership = request.user.memberships.get(
                    xgroup=group,
                    level__gte=self.level,
                    state='enabled',
                )
            except Membership.DoesNotExist:
                membership = None

            request.group = group
            request.membership = membership

            if membership:
                return view_func(request, group, *args, membership=membership, **kwargs)
            else:
                return HttpResponseForbidden()
        return wrapped_view_func