""" SleekXMPP: The Sleek XMPP Library Copyright (C) 2011 Nathanael C. Fritz, Dann Martens (TOMOTON). This file is part of SleekXMPP. See the file LICENSE for copying permission. """ from binding import py2xml, xml2py, xml2fault, fault2xml from threading import RLock import abc import inspect import logging import sleekxmpp import sys import threading import traceback log = logging.getLogger(__name__) def _intercept(method, name, public): def _resolver(instance, *args, **kwargs): log.debug("Locally calling %s.%s with arguments %s.", instance.FQN(), method.__name__, args) try: value = method(instance, *args, **kwargs) if value == NotImplemented: raise InvocationException("Local handler does not implement %s.%s!" % (instance.FQN(), method.__name__)) return value except InvocationException: raise except Exception as e: raise InvocationException("A problem occured calling %s.%s!" % (instance.FQN(), method.__name__), e) _resolver._rpc = public _resolver._rpc_name = method.__name__ if name is None else name return _resolver def remote(function_argument, public = True): ''' Decorator for methods which are remotely callable. This decorator works in conjunction with classes which extend ABC Endpoint. Example: @remote def remote_method(arg1, arg2) Arguments: function_argument -- a stand-in for either the actual method OR a new name (string) for the method. In that case the method is considered mapped: Example: @remote("new_name") def remote_method(arg1, arg2) public -- A flag which indicates if this method should be part of the known dictionary of remote methods. Defaults to True. Example: @remote(False) def remote_method(arg1, arg2) Note: renaming and revising (public vs. private) can be combined. Example: @remote("new_name", False) def remote_method(arg1, arg2) ''' if hasattr(function_argument, '__call__'): return _intercept(function_argument, None, public) else: if not isinstance(function_argument, basestring): if not isinstance(function_argument, bool): raise Exception('Expected an RPC method name or visibility modifier!') else: def _wrap_revised(function): function = _intercept(function, None, function_argument) return function return _wrap_revised def _wrap_remapped(function): function = _intercept(function, function_argument, public) return function return _wrap_remapped class ACL: ''' An Access Control List (ACL) is a list of rules, which are evaluated in order until a match is found. The policy of the matching rule is then applied. Rules are 3-tuples, consisting of a policy enumerated type, a JID expression and a RCP resource expression. Examples: [ (ACL.ALLOW, '*', '*') ] allow everyone everything, no restrictions [ (ACL.DENY, '*', '*') ] deny everyone everything, no restrictions [ (ACL.ALLOW, 'test@xmpp.org/unit', 'test.*'), (ACL.DENY, '*', '*') ] deny everyone everything, except named JID, which is allowed access to endpoint 'test' only. The use of wildcards is allowed in expressions, as follows: '*' everyone, or everything (= all endpoints and methods) 'test@xmpp.org/*' every JID regardless of JID resource '*@xmpp.org/rpc' every JID from domain xmpp.org with JID res 'rpc' 'frank@*' every 'frank', regardless of domain or JID res 'system.*' all methods of endpoint 'system' '*.reboot' all methods reboot regardless of endpoint ''' ALLOW = True DENY = False @classmethod def check(cls, rules, jid, resource): if rules is None: return cls.DENY # No rules means no access! for rule in rules: policy = cls._check(rule, jid, resource) if policy is not None: return policy return cls.DENY # By default if not rule matches, deny access. @classmethod def _check(cls, rule, jid, resource): if cls._match(jid, rule[1]) and cls._match(resource, rule[2]): return rule[0] else: return None @classmethod def _next_token(cls, expression, index): new_index = expression.find('*', index) if new_index == 0: return '' else: if new_index == -1: return expression[index : ] else: return expression[index : new_index] @classmethod def _match(cls, value, expression): #! print "_match [VALUE] %s [EXPR] %s" % (value, expression) index = 0 position = 0 while index < len(expression): token = cls._next_token(expression, index) #! print "[TOKEN] '%s'" % token size = len(token) if size > 0: token_index = value.find(token, position) if token_index == -1: return False else: #! print "[INDEX-OF] %s" % token_index position = token_index + len(token) pass if size == 0: index += 1 else: index += size #! print "index %s position %s" % (index, position) return True ANY_ALL = [ (ACL.ALLOW, '*', '*') ] class RemoteException(Exception): ''' Base exception for RPC. This exception is raised when a problem occurs in the network layer. ''' def __init__(self, message="", cause=None): ''' Initializes a new RemoteException. Arguments: message -- The message accompanying this exception. cause -- The underlying cause of this exception. ''' self._message = message self._cause = cause pass def __str__(self): return repr(self._message) def get_message(self): return self._message def get_cause(self): return self._cause class InvocationException(RemoteException): ''' Exception raised when a problem occurs during the remote invocation of a method. ''' pass class AuthorizationException(RemoteException): ''' Exception raised when the caller is not authorized to invoke the remote method. ''' pass class TimeoutException(Exception): ''' Exception raised when the synchronous execution of a method takes longer than the given threshold because an underlying asynchronous reply did not arrive in time. ''' pass class Callback(object): ''' A base class for callback handlers. ''' __metaclass__ = abc.ABCMeta @abc.abstractproperty def set_value(self, value): return NotImplemented @abc.abstractproperty def cancel_with_error(self, exception): return NotImplemented class Future(Callback): ''' Represents the result of an asynchronous computation. ''' def __init__(self): ''' Initializes a new Future. ''' self._value = None self._exception = None self._event = threading.Event() pass def set_value(self, value): ''' Sets the value of this Future. Once the value is set, a caller blocked on get_value will be able to continue. ''' self._value = value self._event.set() def get_value(self, timeout=None): ''' Gets the value of this Future. This call will block until the result is available, or until an optional timeout expires. When this Future is cancelled with an error, Arguments: timeout -- The maximum waiting time to obtain the value. ''' self._event.wait(timeout) if self._exception: raise self._exception if not self._event.is_set(): raise TimeoutException return self._value def is_done(self): ''' Returns true if a value has been returned. ''' return self._event.is_set() def cancel_with_error(self, exception): ''' Cancels the Future because of an error. Once cancelled, a caller blocked on get_value will be able to continue. ''' self._exception = exception self._event.set() class Endpoint(object): ''' The Endpoint class is an abstract base class for all objects participating in an RPC-enabled XMPP network. A user subclassing this class is required to implement the method: FQN(self) where FQN stands for Fully Qualified Name, an unambiguous name which specifies which object an RPC call refers to. It is the first part in a RPC method name '<fqn>.<method>'. ''' __metaclass__ = abc.ABCMeta def __init__(self, session, target_jid): ''' Initialize a new Endpoint. This constructor should never be invoked by a user, instead it will be called by the factories which instantiate the RPC-enabled objects, of which only the classes are provided by the user. Arguments: session -- An RPC session instance. target_jid -- the identity of the remote XMPP entity. ''' self.session = session self.target_jid = target_jid @abc.abstractproperty def FQN(self): return NotImplemented def get_methods(self): ''' Returns a dictionary of all RPC method names provided by this class. This method returns the actual method names as found in the class definition which have been decorated with: @remote def some_rpc_method(arg1, arg2) Unless: (1) the name has been remapped, in which case the new name will be returned. @remote("new_name") def some_rpc_method(arg1, arg2) (2) the method is set to hidden @remote(False) def some_hidden_method(arg1, arg2) ''' result = dict() for function in dir(self): test_attr = getattr(self, function, None) try: if test_attr._rpc: result[test_attr._rpc_name] = test_attr except Exception: pass return result class Proxy(Endpoint): ''' Implementation of the Proxy pattern which is intended to wrap around Endpoints in order to intercept calls, marshall them and forward them to the remote object. ''' def __init__(self, endpoint, callback = None): ''' Initializes a new Proxy. Arguments: endpoint -- The endpoint which is proxified. ''' self._endpoint = endpoint self._callback = callback def __getattribute__(self, name, *args): if name in ('__dict__', '_endpoint', 'async', '_callback'): return object.__getattribute__(self, name) else: attribute = self._endpoint.__getattribute__(name) if hasattr(attribute, '__call__'): try: if attribute._rpc: def _remote_call(*args, **kwargs): log.debug("Remotely calling '%s.%s' with arguments %s.", self._endpoint.FQN(), attribute._rpc_name, args) return self._endpoint.session._call_remote(self._endpoint.target_jid, "%s.%s" % (self._endpoint.FQN(), attribute._rpc_name), self._callback, *args, **kwargs) return _remote_call except: pass # If the attribute doesn't exist, don't care! return attribute def async(self, callback): return Proxy(self._endpoint, callback) def get_endpoint(self): ''' Returns the proxified endpoint. ''' return self._endpoint def FQN(self): return self._endpoint.FQN() class JabberRPCEntry(object): def __init__(self, endpoint_FQN, call): self._endpoint_FQN = endpoint_FQN self._call = call def call_method(self, args): return_value = self._call(*args) if return_value is None: return return_value else: return self._return(return_value) def get_endpoint_FQN(self): return self._endpoint_FQN def _return(self, *args): return args class RemoteSession(object): ''' A context object for a Jabber-RPC session. ''' def __init__(self, client, session_close_callback): ''' Initializes a new RPC session. Arguments: client -- The SleekXMPP client associated with this session. session_close_callback -- A callback called when the session is closed. ''' self._client = client self._session_close_callback = session_close_callback self._event = threading.Event() self._entries = {} self._callbacks = {} self._acls = {} self._lock = RLock() def _wait(self): self._event.wait() def _notify(self, event): log.debug("RPC Session as %s started.", self._client.boundjid.full) self._client.sendPresence() self._event.set() pass def _register_call(self, endpoint, method, name=None): ''' Registers a method from an endpoint as remotely callable. ''' if name is None: name = method.__name__ key = "%s.%s" % (endpoint, name) log.debug("Registering call handler for %s (%s).", key, method) with self._lock: if key in self._entries: raise KeyError("A handler for %s has already been regisered!" % endpoint) self._entries[key] = JabberRPCEntry(endpoint, method) return key def _register_acl(self, endpoint, acl): log.debug("Registering ACL %s for endpoint %s.", repr(acl), endpoint) with self._lock: self._acls[endpoint] = acl def _register_callback(self, pid, callback): with self._lock: self._callbacks[pid] = callback def forget_callback(self, callback): with self._lock: pid = self._find_key(self._callbacks, callback) if pid is not None: del self._callback[pid] else: raise ValueError("Unknown callback!") pass def _find_key(self, dict, value): """return the key of dictionary dic given the value""" search = [k for k, v in dict.iteritems() if v == value] if len(search) == 0: return None else: return search[0] def _unregister_call(self, key): #removes the registered call with self._lock: if self._entries[key]: del self._entries[key] else: raise ValueError() def new_proxy(self, target_jid, endpoint_cls): ''' Instantiates a new proxy object, which proxies to a remote endpoint. This method uses a class reference without constructor arguments to instantiate the proxy. Arguments: target_jid -- the XMPP entity ID hosting the endpoint. endpoint_cls -- The remote (duck) type. ''' try: argspec = inspect.getargspec(endpoint_cls.__init__) args = [None] * (len(argspec[0]) - 1) result = endpoint_cls(*args) Endpoint.__init__(result, self, target_jid) return Proxy(result) except: traceback.print_exc(file=sys.stdout) def new_handler(self, acl, handler_cls, *args, **kwargs): ''' Instantiates a new handler object, which is called remotely by others. The user can control the effect of the call by implementing the remote method in the local endpoint class. The returned reference can be called locally and will behave as a regular instance. Arguments: acl -- Access control list (see ACL class) handler_clss -- The local (duck) type. *args -- Constructor arguments for the local type. **kwargs -- Constructor keyworded arguments for the local type. ''' argspec = inspect.getargspec(handler_cls.__init__) base_argspec = inspect.getargspec(Endpoint.__init__) if(argspec == base_argspec): result = handler_cls(self, self._client.boundjid.full) else: result = handler_cls(*args, **kwargs) Endpoint.__init__(result, self, self._client.boundjid.full) method_dict = result.get_methods() for method_name, method in method_dict.iteritems(): #!!! self._client.plugin['xep_0009'].register_call(result.FQN(), method, method_name) self._register_call(result.FQN(), method, method_name) self._register_acl(result.FQN(), acl) return result # def is_available(self, targetCls, pto): # return self._client.is_available(pto) def _call_remote(self, pto, pmethod, callback, *arguments): iq = self._client.plugin['xep_0009'].make_iq_method_call(pto, pmethod, py2xml(*arguments)) pid = iq['id'] if callback is None: future = Future() self._register_callback(pid, future) iq.send() return future.get_value(30) else: log.debug("[RemoteSession] _call_remote %s", callback) self._register_callback(pid, callback) iq.send() def close(self): ''' Closes this session. ''' self._client.disconnect(False) self._session_close_callback() def _on_jabber_rpc_method_call(self, iq): iq.enable('rpc_query') params = iq['rpc_query']['method_call']['params'] args = xml2py(params) pmethod = iq['rpc_query']['method_call']['method_name'] try: with self._lock: entry = self._entries[pmethod] rules = self._acls[entry.get_endpoint_FQN()] if ACL.check(rules, iq['from'], pmethod): return_value = entry.call_method(args) else: raise AuthorizationException("Unauthorized access to %s from %s!" % (pmethod, iq['from'])) if return_value is None: return_value = () response = self._client.plugin['xep_0009'].make_iq_method_response(iq['id'], iq['from'], py2xml(*return_value)) response.send() except InvocationException as ie: fault = dict() fault['code'] = 500 fault['string'] = ie.get_message() self._client.plugin['xep_0009']._send_fault(iq, fault2xml(fault)) except AuthorizationException as ae: log.error(ae.get_message()) error = self._client.plugin['xep_0009']._forbidden(iq) error.send() except Exception as e: if isinstance(e, KeyError): log.error("No handler available for %s!", pmethod) error = self._client.plugin['xep_0009']._item_not_found(iq) else: traceback.print_exc(file=sys.stderr) log.error("An unexpected problem occurred invoking method %s!", pmethod) error = self._client.plugin['xep_0009']._undefined_condition(iq) #! print "[REMOTE.PY] _handle_remote_procedure_call AN ERROR SHOULD BE SENT NOW %s " % e error.send() def _on_jabber_rpc_method_response(self, iq): iq.enable('rpc_query') args = xml2py(iq['rpc_query']['method_response']['params']) pid = iq['id'] with self._lock: callback = self._callbacks[pid] del self._callbacks[pid] if(len(args) > 0): callback.set_value(args[0]) else: callback.set_value(None) pass def _on_jabber_rpc_method_response2(self, iq): iq.enable('rpc_query') if iq['rpc_query']['method_response']['fault'] is not None: self._on_jabber_rpc_method_fault(iq) else: args = xml2py(iq['rpc_query']['method_response']['params']) pid = iq['id'] with self._lock: callback = self._callbacks[pid] del self._callbacks[pid] if(len(args) > 0): callback.set_value(args[0]) else: callback.set_value(None) pass def _on_jabber_rpc_method_fault(self, iq): iq.enable('rpc_query') fault = xml2fault(iq['rpc_query']['method_response']['fault']) pid = iq['id'] with self._lock: callback = self._callbacks[pid] del self._callbacks[pid] e = { 500: InvocationException }[fault['code']](fault['string']) callback.cancel_with_error(e) def _on_jabber_rpc_error(self, iq): pid = iq['id'] pmethod = self._client.plugin['xep_0009']._extract_method(iq['rpc_query']) code = iq['error']['code'] type = iq['error']['type'] condition = iq['error']['condition'] #! print("['REMOTE.PY']._BINDING_handle_remote_procedure_error -> ERROR! ERROR! ERROR! Condition is '%s'" % condition) with self._lock: callback = self._callbacks[pid] del self._callbacks[pid] e = { 'item-not-found': RemoteException("No remote handler available for %s at %s!" % (pmethod, iq['from'])), 'forbidden': AuthorizationException("Forbidden to invoke remote handler for %s at %s!" % (pmethod, iq['from'])), 'undefined-condition': RemoteException("An unexpected problem occured trying to invoke %s at %s!" % (pmethod, iq['from'])), }[condition] if e is None: RemoteException("An unexpected exception occurred at %s!" % iq['from']) callback.cancel_with_error(e) class Remote(object): ''' Bootstrap class for Jabber-RPC sessions. New sessions are openend with an existing XMPP client, or one is instantiated on demand. ''' _instance = None _sessions = dict() _lock = threading.RLock() @classmethod def new_session_with_client(cls, client, callback=None): ''' Opens a new session with a given client. Arguments: client -- An XMPP client. callback -- An optional callback which can be used to track the starting state of the session. ''' with Remote._lock: if(client.boundjid.bare in cls._sessions): raise RemoteException("There already is a session associated with these credentials!") else: cls._sessions[client.boundjid.bare] = client; def _session_close_callback(): with Remote._lock: del cls._sessions[client.boundjid.bare] result = RemoteSession(client, _session_close_callback) client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_method_call', result._on_jabber_rpc_method_call, threaded=True) client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_method_response', result._on_jabber_rpc_method_response, threaded=True) client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_method_fault', result._on_jabber_rpc_method_fault, threaded=True) client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_error', result._on_jabber_rpc_error, threaded=True) if callback is None: start_event_handler = result._notify else: start_event_handler = callback client.add_event_handler("session_start", start_event_handler) if client.connect(): client.process(threaded=True) else: raise RemoteException("Could not connect to XMPP server!") pass if callback is None: result._wait() return result @classmethod def new_session(cls, jid, password, callback=None): ''' Opens a new session and instantiates a new XMPP client. Arguments: jid -- The XMPP JID for logging in. password -- The password for logging in. callback -- An optional callback which can be used to track the starting state of the session. ''' client = sleekxmpp.ClientXMPP(jid, password) #? Register plug-ins. client.registerPlugin('xep_0004') # Data Forms client.registerPlugin('xep_0009') # Jabber-RPC client.registerPlugin('xep_0030') # Service Discovery client.registerPlugin('xep_0060') # PubSub client.registerPlugin('xep_0199') # XMPP Ping return cls.new_session_with_client(client, callback)