mediagoblin/db/sql/extratypes.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 from sqlalchemy.types import TypeDecorator, Unicode, TEXT
  19 import json
  20
  21
  22 class PathTupleWithSlashes(TypeDecorator):
  23     "Represents a Tuple of strings as a slash separated string."
  24
  25     impl = Unicode
  26
  27     def process_bind_param(self, value, dialect):
  28         if value is not None:
  29             if len(value) == 0:
  30                 value = None
  31             else:
  32                 value = '/'.join(value)
  33         return value
  34
  35     def process_result_value(self, value, dialect):
  36         if value is not None:
  37             value = tuple(value.split('/'))
  38         return value
  39
  40
  41 # The following class and only this one class is in very
  42 # large parts based on example code from sqlalchemy.
  43 #
  44 # The original copyright notice and license follows:
  45 #     Copyright (C) 2005-2011 the SQLAlchemy authors and contributors <see AUTHORS file>
  46 #
  47 #     This module is part of SQLAlchemy and is released under
  48 #     the MIT License: http://www.opensource.org/licenses/mit-license.php
  49 #
  50 class JSONEncoded(TypeDecorator):
  51     "Represents an immutable structure as a json-encoded string."
  52
  53     impl = TEXT
  54
  55     def process_bind_param(self, value, dialect):
  56         if value is not None:
  57             value = json.dumps(value)
  58         return value
  59
  60     def process_result_value(self, value, dialect):
  61         if value is not None:
  62             value = json.loads(value)
  63         return value