deb-python-autobahn/autobahn/twisted/wamp.py

587 lines
20 KiB
Python

###############################################################################
#
# The MIT License (MIT)
#
# Copyright (c) Tavendo GmbH
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
###############################################################################
from __future__ import absolute_import
import sys
import inspect
from twisted.python import log
from twisted.application import service
from twisted.internet.defer import Deferred, \
maybeDeferred, \
DeferredList, \
inlineCallbacks, \
succeed, \
fail
from autobahn.wamp import protocol
from autobahn.wamp.types import ComponentConfig
from autobahn.websocket.protocol import parseWsUrl
from autobahn.twisted.websocket import WampWebSocketClientFactory
__all__ = (
'FutureMixin',
'ApplicationSession',
'ApplicationSessionFactory',
'ApplicationRunner',
'Application',
'Service'
)
class FutureMixin:
"""
Mixin for Twisted style Futures ("Deferreds").
"""
@staticmethod
def _create_future():
return Deferred()
@staticmethod
def _create_future_success(result=None):
return succeed(result)
@staticmethod
def _create_future_error(error=None):
return fail(error)
@staticmethod
def _as_future(fun, *args, **kwargs):
return maybeDeferred(fun, *args, **kwargs)
@staticmethod
def _resolve_future(future, result=None):
future.callback(result)
@staticmethod
def _reject_future(future, error):
future.errback(error)
@staticmethod
def _add_future_callbacks(future, callback, errback):
return future.addCallbacks(callback, errback)
@staticmethod
def _gather_futures(futures, consume_exceptions=True):
return DeferredList(futures, consumeErrors=consume_exceptions)
class ApplicationSession(FutureMixin, protocol.ApplicationSession):
"""
WAMP application session for Twisted-based applications.
"""
def onUserError(self, e, msg):
"""
Override of wamp.ApplicationSession
"""
# see docs; will print currently-active exception to the logs,
# which is just what we want.
log.err()
# also log the framework-provided error-message
log.err(msg)
class ApplicationSessionFactory(FutureMixin, protocol.ApplicationSessionFactory):
"""
WAMP application session factory for Twisted-based applications.
"""
session = ApplicationSession
"""
The application session class this application session factory will use. Defaults to :class:`autobahn.twisted.wamp.ApplicationSession`.
"""
class ApplicationRunner:
"""
This class is a convenience tool mainly for development and quick hosting
of WAMP application components.
It can host a WAMP application component in a WAMP-over-WebSocket client
connecting to a WAMP router.
"""
def __init__(self, url, realm, extra=None, debug=False, debug_wamp=False, debug_app=False):
"""
:param url: The WebSocket URL of the WAMP router to connect to (e.g. `ws://somehost.com:8090/somepath`)
:type url: unicode
:param realm: The WAMP realm to join the application session to.
:type realm: unicode
:param extra: Optional extra configuration to forward to the application component.
:type extra: dict
:param debug: Turn on low-level debugging.
:type debug: bool
:param debug_wamp: Turn on WAMP-level debugging.
:type debug_wamp: bool
:param debug_app: Turn on app-level debugging.
:type debug_app: bool
"""
self.url = url
self.realm = realm
self.extra = extra or dict()
self.debug = debug
self.debug_wamp = debug_wamp
self.debug_app = debug_app
self.make = None
def run(self, make, start_reactor=True):
"""
Run the application component.
:param make: A factory that produces instances of :class:`autobahn.asyncio.wamp.ApplicationSession`
when called with an instance of :class:`autobahn.wamp.types.ComponentConfig`.
:type make: callable
:param start_reactor: if True (the default) this method starts
the Twisted reactor and doesn't return until the reactor
stops. If there are any problems starting the reactor or
connect()-ing, we stop the reactor and raise the exception
back to the caller.
:returns: None is returned, unless you specify
``start_reactor=False`` in which case the Deferred that
connect() returns is returned; this will callback() with
an IProtocol instance, which will actually be an instance
of :class:`WampWebSocketClientProtocol`
"""
from twisted.internet import reactor
isSecure, host, port, resource, path, params = parseWsUrl(self.url)
# start logging to console
if self.debug or self.debug_wamp or self.debug_app:
log.startLogging(sys.stdout)
# factory for use ApplicationSession
def create():
cfg = ComponentConfig(self.realm, self.extra)
try:
session = make(cfg)
except Exception as e:
if start_reactor:
# the app component could not be created .. fatal
log.err(str(e))
reactor.stop()
else:
# if we didn't start the reactor, it's up to the
# caller to deal with errors
raise
else:
session.debug_app = self.debug_app
return session
# create a WAMP-over-WebSocket transport client factory
transport_factory = WampWebSocketClientFactory(create, url=self.url,
debug=self.debug, debug_wamp=self.debug_wamp)
# start the client from a Twisted endpoint
from twisted.internet.endpoints import clientFromString
if isSecure:
endpoint_descriptor = "ssl:{0}:{1}".format(host, port)
else:
endpoint_descriptor = "tcp:{0}:{1}".format(host, port)
client = clientFromString(reactor, endpoint_descriptor)
d = client.connect(transport_factory)
# if the user didn't ask us to start the reactor, then they
# get to deal with any connect errors themselves.
if start_reactor:
# if an error happens in the connect(), we save the underlying
# exception so that after the event-loop exits we can re-raise
# it to the caller.
class ErrorCollector:
exception = None
def __call__(self, failure):
self.exception = failure.value
# print(failure.getErrorMessage())
reactor.stop()
connect_error = ErrorCollector()
d.addErrback(connect_error)
# now enter the Twisted reactor loop
reactor.run()
# if we exited due to a connection error, raise that to the
# caller
if connect_error.exception:
raise connect_error.exception
else:
# let the caller handle any errors
return d
class _ApplicationSession(ApplicationSession):
"""
WAMP application session class used internally with :class:`autobahn.twisted.app.Application`.
"""
def __init__(self, config, app):
"""
:param config: The component configuration.
:type config: Instance of :class:`autobahn.wamp.types.ComponentConfig`
:param app: The application this session is for.
:type app: Instance of :class:`autobahn.twisted.wamp.Application`.
"""
# noinspection PyArgumentList
ApplicationSession.__init__(self, config)
self.app = app
@inlineCallbacks
def onConnect(self):
"""
Implements :func:`autobahn.wamp.interfaces.ISession.onConnect`
"""
yield self.app._fire_signal('onconnect')
self.join(self.config.realm)
@inlineCallbacks
def onJoin(self, details):
"""
Implements :func:`autobahn.wamp.interfaces.ISession.onJoin`
"""
for uri, proc in self.app._procs:
yield self.register(proc, uri)
for uri, handler in self.app._handlers:
yield self.subscribe(handler, uri)
yield self.app._fire_signal('onjoined')
@inlineCallbacks
def onLeave(self, details):
"""
Implements :func:`autobahn.wamp.interfaces.ISession.onLeave`
"""
yield self.app._fire_signal('onleave')
self.disconnect()
@inlineCallbacks
def onDisconnect(self):
"""
Implements :func:`autobahn.wamp.interfaces.ISession.onDisconnect`
"""
yield self.app._fire_signal('ondisconnect')
class Application:
"""
A WAMP application. The application object provides a simple way of
creating, debugging and running WAMP application components.
"""
def __init__(self, prefix=None):
"""
:param prefix: The application URI prefix to use for procedures and topics,
e.g. ``"com.example.myapp"``.
:type prefix: unicode
"""
self._prefix = prefix
# procedures to be registered once the app session has joined the router/realm
self._procs = []
# event handler to be subscribed once the app session has joined the router/realm
self._handlers = []
# app lifecycle signal handlers
self._signals = {}
# once an app session is connected, this will be here
self.session = None
def __call__(self, config):
"""
Factory creating a WAMP application session for the application.
:param config: Component configuration.
:type config: Instance of :class:`autobahn.wamp.types.ComponentConfig`
:returns: obj -- An object that derives of
:class:`autobahn.twisted.wamp.ApplicationSession`
"""
assert(self.session is None)
self.session = _ApplicationSession(config, self)
return self.session
def run(self, url=u"ws://localhost:8080/ws", realm=u"realm1",
debug=False, debug_wamp=False, debug_app=False,
start_reactor=True):
"""
Run the application.
:param url: The URL of the WAMP router to connect to.
:type url: unicode
:param realm: The realm on the WAMP router to join.
:type realm: unicode
:param debug: Turn on low-level debugging.
:type debug: bool
:param debug_wamp: Turn on WAMP-level debugging.
:type debug_wamp: bool
:param debug_app: Turn on app-level debugging.
:type debug_app: bool
"""
runner = ApplicationRunner(url, realm,
debug=debug, debug_wamp=debug_wamp, debug_app=debug_app)
runner.run(self.__call__, start_reactor)
def register(self, uri=None):
"""
Decorator exposing a function as a remote callable procedure.
The first argument of the decorator should be the URI of the procedure
to register under.
:Example:
.. code-block:: python
@app.register('com.myapp.add2')
def add2(a, b):
return a + b
Above function can then be called remotely over WAMP using the URI `com.myapp.add2`
the function was registered under.
If no URI is given, the URI is constructed from the application URI prefix
and the Python function name.
:Example:
.. code-block:: python
app = Application('com.myapp')
# implicit URI will be 'com.myapp.add2'
@app.register()
def add2(a, b):
return a + b
If the function `yields` (is a co-routine), the `@inlineCallbacks` decorator
will be applied automatically to it. In that case, if you wish to return something,
you should use `returnValue`:
:Example:
.. code-block:: python
from twisted.internet.defer import returnValue
@app.register('com.myapp.add2')
def add2(a, b):
res = yield stuff(a, b)
returnValue(res)
:param uri: The URI of the procedure to register under.
:type uri: unicode
"""
def decorator(func):
if uri:
_uri = uri
else:
assert(self._prefix is not None)
_uri = "{0}.{1}".format(self._prefix, func.__name__)
if inspect.isgeneratorfunction(func):
func = inlineCallbacks(func)
self._procs.append((_uri, func))
return func
return decorator
def subscribe(self, uri=None):
"""
Decorator attaching a function as an event handler.
The first argument of the decorator should be the URI of the topic
to subscribe to. If no URI is given, the URI is constructed from
the application URI prefix and the Python function name.
If the function yield, it will be assumed that it's an asynchronous
process and inlineCallbacks will be applied to it.
:Example:
.. code-block:: python
@app.subscribe('com.myapp.topic1')
def onevent1(x, y):
print("got event on topic1", x, y)
:param uri: The URI of the topic to subscribe to.
:type uri: unicode
"""
def decorator(func):
if uri:
_uri = uri
else:
assert(self._prefix is not None)
_uri = "{0}.{1}".format(self._prefix, func.__name__)
if inspect.isgeneratorfunction(func):
func = inlineCallbacks(func)
self._handlers.append((_uri, func))
return func
return decorator
def signal(self, name):
"""
Decorator attaching a function as handler for application signals.
Signals are local events triggered internally and exposed to the
developer to be able to react to the application lifecycle.
If the function yield, it will be assumed that it's an asynchronous
coroutine and inlineCallbacks will be applied to it.
Current signals :
- `onjoined`: Triggered after the application session has joined the
realm on the router and registered/subscribed all procedures
and event handlers that were setup via decorators.
- `onleave`: Triggered when the application session leaves the realm.
.. code-block:: python
@app.signal('onjoined')
def _():
# do after the app has join a realm
:param name: The name of the signal to watch.
:type name: unicode
"""
def decorator(func):
if inspect.isgeneratorfunction(func):
func = inlineCallbacks(func)
self._signals.setdefault(name, []).append(func)
return func
return decorator
@inlineCallbacks
def _fire_signal(self, name, *args, **kwargs):
"""
Utility method to call all signal handlers for a given signal.
:param name: The signal name.
:type name: str
"""
for handler in self._signals.get(name, []):
try:
# FIXME: what if the signal handler is not a coroutine?
# Why run signal handlers synchronously?
yield handler(*args, **kwargs)
except Exception as e:
# FIXME
log.msg("Warning: exception in signal handler swallowed", e)
class Service(service.MultiService):
"""
A WAMP application as a twisted service.
The application object provides a simple way of creating, debugging and running WAMP application
components inside a traditional twisted application
This manages application lifecycle of the wamp connection using startService and stopService
Using services also allows to create integration tests that properly terminates their connections
It can host a WAMP application component in a WAMP-over-WebSocket client
connecting to a WAMP router.
"""
factory = WampWebSocketClientFactory
def __init__(self, url, realm, make, extra=None,
debug=False, debug_wamp=False, debug_app=False):
"""
:param url: The WebSocket URL of the WAMP router to connect to (e.g. `ws://somehost.com:8090/somepath`)
:type url: unicode
:param realm: The WAMP realm to join the application session to.
:type realm: unicode
:param make: A factory that produces instances of :class:`autobahn.asyncio.wamp.ApplicationSession`
when called with an instance of :class:`autobahn.wamp.types.ComponentConfig`.
:type make: callable
:param extra: Optional extra configuration to forward to the application component.
:type extra: dict
:param debug: Turn on low-level debugging.
:type debug: bool
:param debug_wamp: Turn on WAMP-level debugging.
:type debug_wamp: bool
:param debug_app: Turn on app-level debugging.
:type debug_app: bool
You can replace the attribute factory in order to change connectionLost or connectionFailed behaviour.
The factory attribute must return a WampWebSocketClientFactory object
"""
self.url = url
self.realm = realm
self.extra = extra or dict()
self.debug = debug
self.debug_wamp = debug_wamp
self.debug_app = debug_app
self.make = make
service.MultiService.__init__(self)
self.setupService()
def setupService(self):
"""
Setup the application component.
"""
isSecure, host, port, resource, path, params = parseWsUrl(self.url)
# factory for use ApplicationSession
def create():
cfg = ComponentConfig(self.realm, self.extra)
session = self.make(cfg)
session.debug_app = self.debug_app
return session
# create a WAMP-over-WebSocket transport client factory
transport_factory = self.factory(create, url=self.url,
debug=self.debug, debug_wamp=self.debug_wamp)
# setup the client from a Twisted endpoint
if isSecure:
from twisted.application.internet import SSLClient
clientClass = SSLClient
else:
from twisted.application.internet import TCPClient
clientClass = TCPClient
client = clientClass(host, port, transport_factory)
client.setServiceParent(self)