| # Copyright 2013 The Chromium Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| |
| class DataSource(object): |
| ''' |
| Defines an abstraction for all DataSources. |
| |
| DataSources must have two public methods, get and Cron. A DataSource is |
| initialized with a ServerInstance. Anything in the ServerInstance can be used |
| by the DataSource. |
| |
| DataSources are used to provide templates with access to data. DataSources may |
| not access other DataSources and any logic or data that is useful to other |
| DataSources must be moved to a different class. |
| ''' |
| def Cron(self): |
| '''Must cache all files needed by |get| to persist them. Called on a live |
| file system and can access files not in cache. |
| ''' |
| raise NotImplementedError(self.__class__) |
| |
| def get(self, key): |
| '''Returns a dictionary or list that can be consumed by a template. Called |
| on an offline file system and can only access files in the cache. |
| ''' |
| raise NotImplementedError(self.__class__) |