cabf27424f
Checking for a 'xep' or 'rfc' attribute is more reliable for detecting an old style plugin than 'name'.
293 lines
9.6 KiB
Python
293 lines
9.6 KiB
Python
# -*- encoding: utf-8 -*-
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"""
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sleekxmpp.plugins.base
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~~~~~~~~~~~~~~~~~~~~~~
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This module provides XMPP functionality that
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is specific to client connections.
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Part of SleekXMPP: The Sleek XMPP Library
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:copyright: (c) 2012 Nathanael C. Fritz
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:license: MIT, see LICENSE for more details
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"""
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import sys
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import logging
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import threading
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log = logging.getLogger(__name__)
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#: Associate short string names of plugins with implementations. The
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#: plugin names are based on the spec used by the plugin, such as
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#: `'xep_0030'` for a plugin that implements XEP-0030.
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PLUGIN_REGISTRY = {}
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#: In order to do cascading plugin disabling, reverse dependencies
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#: must be tracked.
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PLUGIN_DEPENDENTS = {}
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#: Only allow one thread to manipulate the plugin registry at a time.
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REGISTRY_LOCK = threading.RLock()
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class PluginNotFound(Exception):
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"""Raised if an unknown plugin is accessed."""
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def register_plugin(impl, name=None):
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"""Add a new plugin implementation to the registry.
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:param class impl: The plugin class.
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The implementation class must provide a :attr:`~BasePlugin.name`
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value that will be used as a short name for enabling and disabling
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the plugin. The name should be based on the specification used by
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the plugin. For example, a plugin implementing XEP-0030 would be
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named `'xep_0030'`.
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"""
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if name is None:
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name = impl.name
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with REGISTRY_LOCK:
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PLUGIN_REGISTRY[name] = impl
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if name not in PLUGIN_DEPENDENTS:
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PLUGIN_DEPENDENTS[name] = set()
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for dep in impl.dependencies:
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if dep not in PLUGIN_DEPENDENTS:
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PLUGIN_DEPENDENTS[dep] = set()
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PLUGIN_DEPENDENTS[dep].add(name)
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def load_plugin(name, module=None):
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"""Find and import a plugin module so that it can be registered.
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This function is called to import plugins that have selected for
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enabling, but no matching registered plugin has been found.
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:param str name: The name of the plugin. It is expected that
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plugins are in packages matching their name,
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even though the plugin class name does not
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have to match.
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:param str module: The name of the base module to search
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for the plugin.
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"""
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try:
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if not module:
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try:
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module = 'sleekxmpp.plugins.%s' % name
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__import__(module)
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mod = sys.modules[module]
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except:
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module = 'sleekxmpp.features.%s' % name
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__import__(module)
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mod = sys.modules[module]
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else:
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__import__(module)
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mod = sys.modules[module]
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# Add older style plugins to the registry.
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if hasattr(mod, name):
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plugin = getattr(mod, name)
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if hasattr(plugin, 'xep') or hasattr(plugin, 'rfc'):
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plugin.name = name
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# Mark the plugin as an older style plugin so
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# we can work around dependency issues.
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plugin.old_style = True
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register_plugin(plugin, name)
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except:
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log.exception("Unable to load plugin: %s", name)
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class PluginManager(object):
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def __init__(self, xmpp, config=None):
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#: We will track all enabled plugins in a set so that we
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#: can enable plugins in batches and pull in dependencies
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#: without problems.
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self._enabled = set()
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#: Maintain references to active plugins.
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self._plugins = {}
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self._plugin_lock = threading.RLock()
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#: Globally set default plugin configuration. This will
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#: be used for plugins that are auto-enabled through
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#: dependency loading.
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self.config = config if config else {}
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self.xmpp = xmpp
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def register(self, plugin, enable=True):
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"""Register a new plugin, and optionally enable it.
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:param class plugin: The implementation class of the plugin
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to register.
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:param bool enable: If ``True``, immediately enable the
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plugin after registration.
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"""
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register_plugin(plugin)
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if enable:
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self.enable(plugin.name)
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def enable(self, name, config=None, enabled=None):
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"""Enable a plugin, including any dependencies.
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:param string name: The short name of the plugin.
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:param dict config: Optional settings dictionary for
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configuring plugin behaviour.
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"""
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top_level = False
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if enabled is None:
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enabled = set()
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with self._plugin_lock:
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if name not in self._enabled:
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enabled.add(name)
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self._enabled.add(name)
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if not self.registered(name):
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load_plugin(name)
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plugin_class = PLUGIN_REGISTRY.get(name, None)
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if not plugin_class:
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raise PluginNotFound(name)
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if config is None:
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config = self.config.get(name, None)
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plugin = plugin_class(self.xmpp, config)
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self._plugins[name] = plugin
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for dep in plugin.dependencies:
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self.enable(dep, enabled=enabled)
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plugin.plugin_init()
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log.debug("Loaded Plugin: %s", plugin.description)
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if top_level:
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for name in enabled:
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if hasattr(self.plugins[name], 'old_style'):
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# Older style plugins require post_init()
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# to run just before stream processing begins,
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# so we don't call it here.
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pass
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self.plugins[name].post_init()
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def enable_all(self, names=None, config=None):
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"""Enable all registered plugins.
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:param list names: A list of plugin names to enable. If
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none are provided, all registered plugins
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will be enabled.
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:param dict config: A dictionary mapping plugin names to
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configuration dictionaries, as used by
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:meth:`~PluginManager.enable`.
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"""
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names = names if names else PLUGIN_REGISTRY.keys()
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if config is None:
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config = {}
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for name in names:
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self.enable(name, config.get(name, {}))
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def enabled(self, name):
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"""Check if a plugin has been enabled.
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:param string name: The name of the plugin to check.
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:return: boolean
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"""
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return name in self._enabled
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def registered(self, name):
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"""Check if a plugin has been registered.
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:param string name: The name of the plugin to check.
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:return: boolean
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"""
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return name in PLUGIN_REGISTRY
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def disable(self, name, _disabled=None):
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"""Disable a plugin, including any dependent upon it.
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:param string name: The name of the plugin to disable.
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:param set _disabled: Private set used to track the
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disabled status of plugins during
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the cascading process.
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"""
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if _disabled is None:
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_disabled = set()
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with self._plugin_lock:
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if name not in _disabled and name in self._enabled:
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_disabled.add(name)
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plugin = self._plugins.get(name, None)
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if plugin is None:
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raise PluginNotFound(name)
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for dep in PLUGIN_DEPENDENTS[name]:
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self.disable(dep, _disabled)
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plugin.plugin_end()
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if name in self._enabled:
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self._enabled.remove(name)
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del self._plugins[name]
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def __keys__(self):
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"""Return the set of enabled plugins."""
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return self._plugins.keys()
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def __getitem__(self, name):
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"""
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Allow plugins to be accessed through the manager as if
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it were a dictionary.
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"""
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plugin = self._plugins.get(name, None)
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if plugin is None:
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raise PluginNotFound(name)
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return plugin
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def __iter__(self):
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"""Return an iterator over the set of enabled plugins."""
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return self._plugins.__iter__()
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def __len__(self):
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"""Return the number of enabled plugins."""
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return len(self._plugins)
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class BasePlugin(object):
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#: A short name for the plugin based on the implemented specification.
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#: For example, a plugin for XEP-0030 would use `'xep_0030'`.
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name = ''
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#: A longer name for the plugin, describing its purpose. For example,
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#: a plugin for XEP-0030 would use `'Service Discovery'` as its
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#: description value.
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description = ''
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#: Some plugins may depend on others in order to function properly.
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#: Any plugin names included in :attr:`~BasePlugin.dependencies` will
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#: be initialized as needed if this plugin is enabled.
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dependencies = set()
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def __init__(self, xmpp, config=None):
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self.xmpp = xmpp
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#: A plugin's behaviour may be configurable, in which case those
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#: configuration settings will be provided as a dictionary.
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self.config = config if config is not None else {}
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def plugin_init(self):
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"""Initialize plugin state, such as registering event handlers."""
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pass
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def plugin_end(self):
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"""Cleanup plugin state, and prepare for plugin removal."""
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pass
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def post_init(self):
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"""Initialize any cross-plugin state.
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Only needed if the plugin has circular dependencies.
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"""
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pass
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base_plugin = BasePlugin
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