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
  28 logger = logging.getLogger(__name__)
  29
  30
  31 def requires_token(token_name, denied_template=None):
  32     """
  33     returns a decorator that checks if the security token in the 'token' GET
  34     parameter matches the requires token for the resource. The protected
  35     resource is indicated by
  36     * the username parameter passed to the decorated function
  37     * token_name passed to this method
  38
  39     The decorated method is returned, if
  40     * no token is required for the resource
  41     * the token in the 'token' GET parameter matches the required token
  42
  43     If the passed token does not match
  44     * the denied_template is rendered and returned if given
  45     * HttpResponseForbidden is returned, if denied_template is not given
  46     """
  47
  48     def decorator(fn):
  49         @wraps(fn)
  50         def tmp(request, username, *args, **kwargs):
  51
  52             User = get_user_model()
  53             user = get_object_or_404(User, username=username)
  54             token = user.profile.get_token(token_name)
  55             u_token = request.GET.get("token", "")
  56
  57             if token == "" or token == u_token:
  58                 return fn(request, username, *args, **kwargs)
  59
  60             else:
  61                 if denied_template:
  62                     return render(request, denied_template, {"other_user": user})
  63
  64                 else:
  65                     return HttpResponseForbidden()
  66
  67         return tmp
  68
  69     return decorator
  70
  71
  72 def allowed_methods(methods):
  73     def decorator(fn):
  74         @wraps(fn)
  75         def tmp(request, *args, **kwargs):
  76             if request.method in methods:
  77                 return fn(request, *args, **kwargs)
  78             else:
  79                 return HttpResponseNotAllowed(methods)
  80
  81         return tmp
  82
  83     return decorator
  84
  85
  86 def query_if_required():
  87     """If required, queries some resource before calling the function
  88
  89     The decorated method is expected to be bound and its class is
  90     expected to have define the methods _needs_query() and _query().
  91     """
  92
  93     def decorator(f):
  94         @wraps(f)
  95         def wrapper(self, *args, **kwargs):
  96
  97             if self._needs_query():
  98                 self._query()
  99
 100             return f(self, *args, **kwargs)
 101
 102         return wrapper
 103
 104     return decorator
 105
 106
 107 def cors_origin(allowed_origin="*"):
 108     """Adds an Access-Control-Allow-Origin header to the response"""
 109
 110     def decorator(f):
 111         @wraps(f)
 112         def wrapper(*args, **kwargs):
 113             resp = f(*args, **kwargs)
 114             resp["Access-Control-Allow-Origin"] = allowed_origin
 115             return resp
 116
 117         return wrapper
 118
 119     return decorator