""" Slixmpp: The Slick XMPP Library Copyright (C) 2011 Nathanael C. Fritz, Lance J.T. Stout This file is part of Slixmpp. See the file LICENSE for copying permission. """ import logging import time from slixmpp import Iq from slixmpp.exceptions import XMPPError from slixmpp.xmlstream.handler import Callback from slixmpp.xmlstream.matcher import StanzaPath from slixmpp.xmlstream import register_stanza_plugin, JID from slixmpp.plugins import BasePlugin from slixmpp.plugins.xep_0050 import stanza from slixmpp.plugins.xep_0050 import Command from slixmpp.plugins.xep_0004 import Form log = logging.getLogger(__name__) class XEP_0050(BasePlugin): """ XEP-0050: Ad-Hoc Commands XMPP's Adhoc Commands provides a generic workflow mechanism for interacting with applications. The result is similar to menu selections and multi-step dialogs in normal desktop applications. Clients do not need to know in advance what commands are provided by any particular application or agent. While adhoc commands provide similar functionality to Jabber-RPC, adhoc commands are used primarily for human interaction. Also see Events: command_execute -- Received a command with action="execute" command_next -- Received a command with action="next" command_complete -- Received a command with action="complete" command_cancel -- Received a command with action="cancel" Attributes: commands -- A dictionary mapping JID/node pairs to command names and handlers. sessions -- A dictionary or equivalent backend mapping session IDs to dictionaries containing data relevant to a command's session. Methods: plugin_init -- Overrides BasePlugin.plugin_init post_init -- Overrides BasePlugin.post_init new_session -- Return a new session ID. prep_handlers -- Placeholder. May call with a list of handlers to prepare them for use with the session storage backend, if needed. set_backend -- Replace the default session storage with some external storage mechanism, such as a database. The provided backend wrapper must be able to act using the same syntax as a dictionary. add_command -- Add a command for use by external entitites. get_commands -- Retrieve a list of commands provided by a remote agent. send_command -- Send a command request to a remote agent. start_command -- Command user API: initiate a command session continue_command -- Command user API: proceed to the next step cancel_command -- Command user API: cancel a command complete_command -- Command user API: finish a command terminate_command -- Command user API: delete a command's session """ name = 'xep_0050' description = 'XEP-0050: Ad-Hoc Commands' dependencies = set(['xep_0030', 'xep_0004']) stanza = stanza default_config = { 'session_db': None } def plugin_init(self): """Start the XEP-0050 plugin.""" self.sessions = self.session_db if self.sessions is None: self.sessions = {} self.commands = {} self.xmpp.register_handler( Callback("Ad-Hoc Execute", StanzaPath('iq@type=set/command'), self._handle_command)) register_stanza_plugin(Iq, Command) register_stanza_plugin(Command, Form) self.xmpp.add_event_handler('command_execute', self._handle_command_start) self.xmpp.add_event_handler('command_next', self._handle_command_next) self.xmpp.add_event_handler('command_cancel', self._handle_command_cancel) self.xmpp.add_event_handler('command_complete', self._handle_command_complete) def plugin_end(self): self.xmpp.del_event_handler('command_execute', self._handle_command_start) self.xmpp.del_event_handler('command_next', self._handle_command_next) self.xmpp.del_event_handler('command_cancel', self._handle_command_cancel) self.xmpp.del_event_handler('command_complete', self._handle_command_complete) self.xmpp.remove_handler('Ad-Hoc Execute') self.xmpp['xep_0030'].del_feature(feature=Command.namespace) self.xmpp['xep_0030'].set_items(node=Command.namespace, items=tuple()) def session_bind(self, jid): self.xmpp['xep_0030'].add_feature(Command.namespace) self.xmpp['xep_0030'].set_items(node=Command.namespace, items=tuple()) def set_backend(self, db): """ Replace the default session storage dictionary with a generic, external data storage mechanism. The replacement backend must be able to interact through the same syntax and interfaces as a normal dictionary. Arguments: db -- The new session storage mechanism. """ self.sessions = db def prep_handlers(self, handlers, **kwargs): """ Prepare a list of functions for use by the backend service. Intended to be replaced by the backend service as needed. Arguments: handlers -- A list of function pointers **kwargs -- Any additional parameters required by the backend. """ pass # ================================================================= # Server side (command provider) API def add_command(self, jid=None, node=None, name='', handler=None): """ Make a new command available to external entities. Access control may be implemented in the provided handler. Command workflow is done across a sequence of command handlers. The first handler is given the initial Iq stanza of the request in order to support access control. Subsequent handlers are given only the payload items of the command. All handlers will receive the command's session data. Arguments: jid -- The JID that will expose the command. node -- The node associated with the command. name -- A human readable name for the command. handler -- A function that will generate the response to the initial command request, as well as enforcing any access control policies. """ if jid is None: jid = self.xmpp.boundjid elif not isinstance(jid, JID): jid = JID(jid) item_jid = jid.full self.xmpp['xep_0030'].add_identity(category='automation', itype='command-list', name='Ad-Hoc commands', node=Command.namespace, jid=jid) self.xmpp['xep_0030'].add_item(jid=item_jid, name=name, node=Command.namespace, subnode=node, ijid=jid) self.xmpp['xep_0030'].add_identity(category='automation', itype='command-node', name=name, node=node, jid=jid) self.xmpp['xep_0030'].add_feature(Command.namespace, None, jid) self.commands[(item_jid, node)] = (name, handler) def new_session(self): """Return a new session ID.""" return str(time.time()) + '-' + self.xmpp.new_id() def _handle_command(self, iq): """Raise command events based on the command action.""" self.xmpp.event('command_%s' % iq['command']['action'], iq) def _handle_command_start(self, iq): """ Process an initial request to execute a command. Arguments: iq -- The command execution request. """ sessionid = self.new_session() node = iq['command']['node'] key = (iq['to'].full, node) name, handler = self.commands.get(key, ('Not found', None)) if not handler: log.debug('Command not found: %s, %s', key, self.commands) raise XMPPError('item-not-found') payload = [] for stanza in iq['command']['substanzas']: payload.append(stanza) if len(payload) == 1: payload = payload[0] interfaces = set([item.plugin_attrib for item in payload]) payload_classes = set([item.__class__ for item in payload]) initial_session = {'id': sessionid, 'from': iq['from'], 'to': iq['to'], 'node': node, 'payload': payload, 'interfaces': interfaces, 'payload_classes': payload_classes, 'notes': None, 'has_next': False, 'allow_complete': False, 'allow_prev': False, 'past': [], 'next': None, 'prev': None, 'cancel': None} session = handler(iq, initial_session) self._process_command_response(iq, session) def _handle_command_next(self, iq): """ Process a request for the next step in the workflow for a command with multiple steps. Arguments: iq -- The command continuation request. """ sessionid = iq['command']['sessionid'] session = self.sessions.get(sessionid) if session: handler = session['next'] interfaces = session['interfaces'] results = [] for stanza in iq['command']['substanzas']: if stanza.plugin_attrib in interfaces: results.append(stanza) if len(results) == 1: results = results[0] session = handler(results, session) self._process_command_response(iq, session) else: raise XMPPError('item-not-found') def _handle_command_prev(self, iq): """ Process a request for the prev step in the workflow for a command with multiple steps. Arguments: iq -- The command continuation request. """ sessionid = iq['command']['sessionid'] session = self.sessions.get(sessionid) if session: handler = session['prev'] interfaces = session['interfaces'] results = [] for stanza in iq['command']['substanzas']: if stanza.plugin_attrib in interfaces: results.append(stanza) if len(results) == 1: results = results[0] session = handler(results, session) self._process_command_response(iq, session) else: raise XMPPError('item-not-found') def _process_command_response(self, iq, session): """ Generate a command reply stanza based on the provided session data. Arguments: iq -- The command request stanza. session -- A dictionary of relevant session data. """ sessionid = session['id'] payload = session['payload'] if payload is None: payload = [] if not isinstance(payload, list): payload = [payload] interfaces = session.get('interfaces', set()) payload_classes = session.get('payload_classes', set()) interfaces.update(set([item.plugin_attrib for item in payload])) payload_classes.update(set([item.__class__ for item in payload])) session['interfaces'] = interfaces session['payload_classes'] = payload_classes self.sessions[sessionid] = session for item in payload: register_stanza_plugin(Command, item.__class__, iterable=True) iq = iq.reply() iq['command']['node'] = session['node'] iq['command']['sessionid'] = session['id'] if session['next'] is None: iq['command']['actions'] = [] iq['command']['status'] = 'completed' elif session['has_next']: actions = ['next'] if session['allow_complete']: actions.append('complete') if session['allow_prev']: actions.append('prev') iq['command']['actions'] = actions iq['command']['status'] = 'executing' else: iq['command']['actions'] = ['complete'] iq['command']['status'] = 'executing' iq['command']['notes'] = session['notes'] for item in payload: iq['command'].append(item) iq.send() def _handle_command_cancel(self, iq): """ Process a request to cancel a command's execution. Arguments: iq -- The command cancellation request. """ node = iq['command']['node'] sessionid = iq['command']['sessionid'] session = self.sessions.get(sessionid) if session: handler = session['cancel'] if handler: handler(iq, session) del self.sessions[sessionid] iq = iq.reply() iq['command']['node'] = node iq['command']['sessionid'] = sessionid iq['command']['status'] = 'canceled' iq['command']['notes'] = session['notes'] iq.send() else: raise XMPPError('item-not-found') def _handle_command_complete(self, iq): """ Process a request to finish the execution of command and terminate the workflow. All data related to the command session will be removed. Arguments: iq -- The command completion request. """ node = iq['command']['node'] sessionid = iq['command']['sessionid'] session = self.sessions.get(sessionid) if session: handler = session['next'] interfaces = session['interfaces'] results = [] for stanza in iq['command']['substanzas']: if stanza.plugin_attrib in interfaces: results.append(stanza) if len(results) == 1: results = results[0] if handler: handler(results, session) del self.sessions[sessionid] iq = iq.reply() iq['command']['node'] = node iq['command']['sessionid'] = sessionid iq['command']['actions'] = [] iq['command']['status'] = 'completed' iq['command']['notes'] = session['notes'] iq.send() else: raise XMPPError('item-not-found') # ================================================================= # Client side (command user) API def get_commands(self, jid, **kwargs): """ Return a list of commands provided by a given JID. Arguments: jid -- The JID to query for commands. local -- If true, then the query is for a JID/node combination handled by this Slixmpp instance and no stanzas need to be sent. Otherwise, a disco stanza must be sent to the remove JID to retrieve the items. ifrom -- Specifiy the sender's JID. timeout -- The time in seconds to block while waiting for a reply. If None, then wait indefinitely. callback -- Optional callback to execute when a reply is received instead of blocking and waiting for the reply. iterator -- If True, return a result set iterator using the XEP-0059 plugin, if the plugin is loaded. Otherwise the parameter is ignored. """ return self.xmpp['xep_0030'].get_items(jid=jid, node=Command.namespace, **kwargs) def send_command(self, jid, node, ifrom=None, action='execute', payload=None, sessionid=None, flow=False, **kwargs): """ Create and send a command stanza, without using the provided workflow management APIs. Arguments: jid -- The JID to send the command request or result. node -- The node for the command. ifrom -- Specify the sender's JID. action -- May be one of: execute, cancel, complete, or cancel. payload -- Either a list of payload items, or a single payload item such as a data form. sessionid -- The current session's ID value. flow -- If True, process the Iq result using the command workflow methods contained in the session instead of returning the response stanza itself. Defaults to False. timeout -- The length of time (in seconds) to wait for a response before exiting the send call if blocking is used. Defaults to slixmpp.xmlstream.RESPONSE_TIMEOUT callback -- Optional reference to a stream handler function. Will be executed when a reply stanza is received if flow=False. """ iq = self.xmpp.Iq() iq['type'] = 'set' iq['to'] = jid iq['from'] = ifrom iq['command']['node'] = node iq['command']['action'] = action if sessionid is not None: iq['command']['sessionid'] = sessionid if payload is not None: if not isinstance(payload, list): payload = [payload] for item in payload: iq['command'].append(item) if not flow: return iq.send(**kwargs) else: iq.send(callback=self._handle_command_result) def start_command(self, jid, node, session, ifrom=None): """ Initiate executing a command provided by a remote agent. The provided session dictionary should contain: next -- A handler for processing the command result. error -- A handler for processing any error stanzas generated by the request. Arguments: jid -- The JID to send the command request. node -- The node for the desired command. session -- A dictionary of relevant session data. ifrom -- Optionally specify the sender's JID. """ session['jid'] = jid session['node'] = node session['timestamp'] = time.time() if 'payload' not in session: session['payload'] = None iq = self.xmpp.Iq() iq['type'] = 'set' iq['to'] = jid iq['from'] = ifrom session['from'] = ifrom iq['command']['node'] = node iq['command']['action'] = 'execute' if session['payload'] is not None: payload = session['payload'] if not isinstance(payload, list): payload = list(payload) for stanza in payload: iq['command'].append(stanza) sessionid = 'client:pending_' + iq['id'] session['id'] = sessionid self.sessions[sessionid] = session iq.send(callback=self._handle_command_result) def continue_command(self, session, direction='next'): """ Execute the next action of the command. Arguments: session -- All stored data relevant to the current command session. """ sessionid = 'client:' + session['id'] self.sessions[sessionid] = session self.send_command(session['jid'], session['node'], ifrom=session.get('from', None), action=direction, payload=session.get('payload', None), sessionid=session['id'], flow=True) def cancel_command(self, session): """ Cancel the execution of a command. Arguments: session -- All stored data relevant to the current command session. """ sessionid = 'client:' + session['id'] self.sessions[sessionid] = session self.send_command(session['jid'], session['node'], ifrom=session.get('from', None), action='cancel', payload=session.get('payload', None), sessionid=session['id'], flow=True) def complete_command(self, session): """ Finish the execution of a command workflow. Arguments: session -- All stored data relevant to the current command session. """ sessionid = 'client:' + session['id'] self.sessions[sessionid] = session self.send_command(session['jid'], session['node'], ifrom=session.get('from', None), action='complete', payload=session.get('payload', None), sessionid=session['id'], flow=True) def terminate_command(self, session): """ Delete a command's session after a command has completed or an error has occured. Arguments: session -- All stored data relevant to the current command session. """ sessionid = 'client:' + session['id'] try: del self.sessions[sessionid] except Exception as e: log.error("Error deleting adhoc command session: %s" % e.message) def _handle_command_result(self, iq): """ Process the results of a command request. Will execute the 'next' handler stored in the session data, or the 'error' handler depending on the Iq's type. Arguments: iq -- The command response. """ sessionid = 'client:' + iq['command']['sessionid'] pending = False if sessionid not in self.sessions: pending = True pendingid = 'client:pending_' + iq['id'] if pendingid not in self.sessions: return sessionid = pendingid session = self.sessions[sessionid] sessionid = 'client:' + iq['command']['sessionid'] session['id'] = iq['command']['sessionid'] self.sessions[sessionid] = session if pending: del self.sessions[pendingid] handler_type = 'next' if iq['type'] == 'error': handler_type = 'error' handler = session.get(handler_type, None) if handler: handler(iq, session) elif iq['type'] == 'error': self.terminate_command(session) if iq['command']['status'] == 'completed': self.terminate_command(session)