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Diffstat (limited to 'sleekxmpp/plugins/xep_0009/remote.py')
| -rw-r--r-- | sleekxmpp/plugins/xep_0009/remote.py | 742 |
1 files changed, 742 insertions, 0 deletions
diff --git a/sleekxmpp/plugins/xep_0009/remote.py b/sleekxmpp/plugins/xep_0009/remote.py new file mode 100644 index 00000000..8c08e8f3 --- /dev/null +++ b/sleekxmpp/plugins/xep_0009/remote.py @@ -0,0 +1,742 @@ +""" + 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! + jid = str(jid) # Check the string representation of the JID. + if not jid: + return cls.DENY # Can't check an empty JID. + 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) + |