mygpo/decorators.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # gPodder - A media aggregator and podcast client
   4 # Copyright (c) 2005-2009 Thomas Perl and the gPodder Team
   5 #
   6 # gPodder is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # gPodder is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 #
  19
  20 from functools import wraps
  21
  22 from django.shortcuts import render, get_object_or_404
  23 from django.http import HttpResponseForbidden, HttpResponseNotAllowed
  24 from django.contrib.auth import get_user_model
  25
  26 import logging
  27 logger = logging.getLogger(__name__)
  28
  29
  30 def requires_token(token_name, denied_template=None):
  31     """
  32     returns a decorator that checks if the security token in the 'token' GET
  33     parameter matches the requires token for the resource. The protected
  34     resource is indicated by
  35     * the username parameter passed to the decorated function
  36     * token_name passed to this method
  37
  38     The decorated method is returned, if
  39     * no token is required for the resource
  40     * the token in the 'token' GET parameter matches the required token
  41
  42     If the passed token does not match
  43     * the denied_template is rendered and returned if given
  44     * HttpResponseForbidden is returned, if denied_template is not given
  45     """
  46     def decorator(fn):
  47         @wraps(fn)
  48         def tmp(request, username, *args, **kwargs):
  49
  50             User = get_user_model()
  51             user = get_object_or_404(User, username=username)
  52             token = user.profile.get_token(token_name)
  53             u_token = request.GET.get('token', '')
  54
  55             if token == '' or token == u_token:
  56                 return fn(request, username, *args, **kwargs)
  57
  58             else:
  59                 if denied_template:
  60                     return render(request, denied_template, {
  61                         'other_user': user
  62                     })
  63
  64                 else:
  65                     return HttpResponseForbidden()
  66
  67         return tmp
  68     return decorator
  69
  70
  71 def allowed_methods(methods):
  72     def decorator(fn):
  73         @wraps(fn)
  74         def tmp(request, *args, **kwargs):
  75             if request.method in methods:
  76                 return fn(request, *args, **kwargs)
  77             else:
  78                 return HttpResponseNotAllowed(methods)
  79
  80         return tmp
  81
  82     return decorator
  83
  84
  85 def query_if_required():
  86     """ If required, queries some resource before calling the function
  87
  88     The decorated method is expected to be bound and its class is
  89     expected to have define the methods _needs_query() and _query().
  90     """
  91
  92     def decorator(f):
  93         @wraps(f)
  94         def wrapper(self, *args, **kwargs):
  95
  96             if self._needs_query():
  97                 self._query()
  98
  99             return f(self, *args, **kwargs)
 100
 101         return wrapper
 102     return decorator
 103
 104
 105 def cors_origin(allowed_origin='*'):
 106     """ Adds an Access-Control-Allow-Origin header to the response """
 107
 108     def decorator(f):
 109         @wraps(f)
 110         def wrapper(*args, **kwargs):
 111             resp = f(*args, **kwargs)
 112             resp['Access-Control-Allow-Origin'] = allowed_origin
 113             return resp
 114
 115         return wrapper
 116     return decorator