Esempio n. 1
0
def deserialize_msg(msg):
    # NOTE(russellb): Hang on to your hats, this road is about to
    # get a little bumpy.
    #
    # Robustness Principle:
    #    "Be strict in what you send, liberal in what you accept."
    #
    # At this point we have to do a bit of guessing about what it
    # is we just received.  Here is the set of possibilities:
    #
    # 1) We received a dict.  This could be 2 things:
    #
    #   a) Inspect it to see if it looks like a standard message envelope.
    #      If so, great!
    #
    #   b) If it doesn't look like a standard message envelope, it could either
    #      be a notification (which we don't wrap), or a message from before
    #      we added a message envelope (referred to as version 1.0).
    #      Just return the message as-is.
    #
    # 2) It's any other non-dict type.  Just return it and hope for the best.
    #    This case covers return values from rpc.call() from before message
    #    envelopes were used.  (messages to call a method were always a dict)

    if not isinstance(msg, dict):
        # See #2 above.
        return msg

    base_envelope_keys = (_VERSION_KEY, _MESSAGE_KEY)
    if not all(map(lambda key: key in msg, base_envelope_keys)):
        #  See #1.b above.
        return msg

    # At this point we think we have the message envelope
    # format we were expecting. (#1.a above)

    if not version_is_compatible(_RPC_ENVELOPE_VERSION, msg[_VERSION_KEY]):
        raise UnsupportedRpcEnvelopeVersion(version=msg[_VERSION_KEY])

    raw_msg = jsonutils.loads(msg[_MESSAGE_KEY])

    return raw_msg
Esempio n. 2
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def deserialize_remote_exception(conf, data):
    failure = jsonutils.loads(str(data))

    trace = failure.get('tb', [])
    message = failure.get('message', "") + "\n" + "\n".join(trace)
    name = failure.get('class')
    module = failure.get('module')

    # NOTE(ameade): We DO NOT want to allow just any module to be imported, in
    # order to prevent arbitrary code execution.
    if not module in conf.allowed_rpc_exception_modules:
        return RemoteError(name, failure.get('message'), trace)

    try:
        mod = importutils.import_module(module)
        klass = getattr(mod, name)
        if not issubclass(klass, Exception):
            raise TypeError("Can only deserialize Exceptions")

        failure = klass(**failure.get('kwargs', {}))
    except (AttributeError, TypeError, ImportError):
        return RemoteError(name, failure.get('message'), trace)

    ex_type = type(failure)
    str_override = lambda self: message
    new_ex_type = type(ex_type.__name__ + "_Remote", (ex_type,),
                       {'__str__': str_override, '__unicode__': str_override})
    try:
        # NOTE(ameade): Dynamically create a new exception type and swap it in
        # as the new type for the exception. This only works on user defined
        # Exceptions and not core python exceptions. This is important because
        # we cannot necessarily change an exception message so we must override
        # the __str__ method.
        failure.__class__ = new_ex_type
    except TypeError:
        # NOTE(ameade): If a core exception then just add the traceback to the
        # first exception argument.
        failure.args = (message,) + failure.args[1:]
    return failure
Esempio n. 3
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 def _from_json(self, datastring):
     try:
         return jsonutils.loads(datastring)
     except ValueError:
         msg = _("cannot understand JSON")
         raise exception.MalformedRequestBody(reason=msg)