text: # 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/>.
  
  import json
  import logging
  
  from mediagoblin.db.models import User, AccessToken
  from mediagoblin.oauth.tools.request import decode_authorization_header
  
  _log = logging.getLogger(__name__)
  
  
  # MIME-Types
  form_encoded = "application/x-www-form-urlencoded"
  json_encoded = "application/json"
  
  
  def setup_user_in_request(request):
      """
      Examine a request and tack on a request.user parameter if that's
      appropriate.
      """
      # If API request the user will be associated with the access token
      authorization = decode_authorization_header(request.headers)
  
      if authorization.get(u"access_token"):
          # Check authorization header.
          token = authorization[u"oauth_token"]
          token = AccessToken.query.filter_by(token=token).first()
          if token is not None:
              request.user = token.user
              return
  
  
      if 'user_id' not in request.session:
          request.user = None
          return
  
      request.user = User.query.get(request.session['user_id'])
  
      if not request.user:
          # Something's wrong... this user doesn't exist?  Invalidate
          # this session.
          _log.warn("Killing session for user id %r", request.session['user_id'])
          request.session.delete()
  
  def decode_request(request):
      """ Decodes a request based on MIME-Type """
      data = request.data
  
      if request.content_type == json_encoded:
          data = json.loads(data)
      elif request.content_type == form_encoded or request.content_type == "":
          data = request.form
      else:
          data = ""
      return data
  