| # Copyright 2010 Google Inc. |
| # |
| # Permission is hereby granted, free of charge, to any person obtaining a |
| # copy of this software and associated documentation files (the |
| # "Software"), to deal in the Software without restriction, including |
| # without limitation the rights to use, copy, modify, merge, publish, dis- |
| # tribute, sublicense, and/or sell copies of the Software, and to permit |
| # persons to whom the Software is furnished to do so, subject to the fol- |
| # lowing conditions: |
| # |
| # The above copyright notice and this permission notice shall be included |
| # in all copies or substantial portions of the Software. |
| # |
| # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL- |
| # ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT |
| # SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| # IN THE SOFTWARE. |
| |
| |
| """ |
| Implements plugin related api. |
| |
| To define a new plugin just subclass Plugin, like this. |
| |
| class AuthPlugin(Plugin): |
| pass |
| |
| Then start creating subclasses of your new plugin. |
| |
| class MyFancyAuth(AuthPlugin): |
| capability = ['sign', 'vmac'] |
| |
| The actual interface is duck typed. |
| |
| """ |
| |
| import glob |
| import imp, os.path |
| |
| class Plugin(object): |
| """Base class for all plugins.""" |
| |
| capability = [] |
| |
| @classmethod |
| def is_capable(cls, requested_capability): |
| """Returns true if the requested capability is supported by this plugin |
| """ |
| for c in requested_capability: |
| if not c in cls.capability: |
| return False |
| return True |
| |
| def get_plugin(cls, requested_capability=None): |
| if not requested_capability: |
| requested_capability = [] |
| result = [] |
| for handler in cls.__subclasses__(): |
| if handler.is_capable(requested_capability): |
| result.append(handler) |
| return result |
| |
| def _import_module(filename): |
| (path, name) = os.path.split(filename) |
| (name, ext) = os.path.splitext(name) |
| |
| (file, filename, data) = imp.find_module(name, [path]) |
| try: |
| return imp.load_module(name, file, filename, data) |
| finally: |
| if file: |
| file.close() |
| |
| _plugin_loaded = False |
| |
| def load_plugins(config): |
| global _plugin_loaded |
| if _plugin_loaded: |
| return |
| _plugin_loaded = True |
| |
| if not config.has_option('Plugin', 'plugin_directory'): |
| return |
| directory = config.get('Plugin', 'plugin_directory') |
| for file in glob.glob(os.path.join(directory, '*.py')): |
| _import_module(file) |
| |