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Introduced new XEP-0009 into develop.

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Dann Martens
2011-01-13 08:40:53 +01:00
parent b3353183f3
commit 3a12cdbd13
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sleekxmpp/plugins/xep_0009/remote.py Normal file
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"""
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 self._entries.has_key(key):
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:
print "[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)
client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_method_response', result._on_jabber_rpc_method_response)
client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_method_fault', result._on_jabber_rpc_method_fault)
client.plugin['xep_0009'].xmpp.add_event_handler('jabber_rpc_error', result._on_jabber_rpc_error)
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)