def enter_main_loop(self):
"""
Wait for requests from the other side.
The communication protocol for remote procedure calls is as follows:
- Every request is a dictionary containing at least a ``command`` key
with a string value (the name of the method to invoke).
- The value of the optional ``arguments`` key gives a list of
positional arguments to pass to the method.
- The value of the optional ``keyword-arguments`` key gives a
dictionary of keyword arguments to pass to the method.
Responses are structured as follows:
- Every response is a dictionary containing at least a ``success`` key
with a boolean value.
- If ``success=True`` the key ``result`` gives the return value of the
method.
- If ``success=False`` the key ``error`` gives a string explaining what
went wrong.
:raises: :py:exc:`ProtocolError` when the remote side violates the
defined protocol.
"""
while True:
request = self.read()
method_name = request.get('method')
method = getattr(self, method_name, None)
args = request.get('args', [])
kw = request.get('kw', {})
if method and not method_name.startswith('_'):
try:
logger.info("Remote is calling local method %s ..",
format_call(method_name, *args, **kw))
result = method(*args, **kw)
logger.info(
"Local method call was successful and returned result %r.",
result)
self.write(dict(success=True, result=result))
except Exception as e:
logger.exception(
"Swallowing unexpected exception during local method call so we don't crash!"
)
self.write(dict(success=False, error=str(e)))
else:
logger.warning("Remote tried to call unsupported method %s!",
method_name)
self.write(
dict(success=False,
error="Method %s not supported" % method_name))
def enter_main_loop(self):
"""
Wait for requests from the other side.
The communication protocol for remote procedure calls is as follows:
- Every request is a dictionary containing at least a ``command`` key
with a string value (the name of the method to invoke).
- The value of the optional ``arguments`` key gives a list of
positional arguments to pass to the method.
- The value of the optional ``keyword-arguments`` key gives a
dictionary of keyword arguments to pass to the method.
Responses are structured as follows:
- Every response is a dictionary containing at least a ``success`` key
with a boolean value.
- If ``success=True`` the key ``result`` gives the return value of the
method.
- If ``success=False`` the key ``error`` gives a string explaining what
went wrong.
:raises: :exc:`ProtocolError` when the remote side violates the
defined protocol.
"""
while True:
request = self.read()
method_name = request.get('method')
method = getattr(self, method_name, None)
args = request.get('args', [])
kw = request.get('kw', {})
if method and not method_name.startswith('_'):
try:
logger.info("Remote is calling local method %s ..", format_call(method_name, *args, **kw))
result = method(*args, **kw)
logger.info("Local method call was successful and returned result %r.", result)
self.write(dict(success=True, result=result))
except Exception as e:
logger.exception("Swallowing unexpected exception during local method call so we don't crash!")
self.write(dict(success=False, error=str(e)))
else:
logger.warning("Remote tried to call unsupported method %s!", method_name)
self.write(dict(success=False, error="Method %s not supported" % method_name))
def call_remote_method(self, method, *args, **kw):
"""
Call a method on the remote object.
:param method: The name of the method to call (a string).
:param args: The positional arguments for the method.
:param kw: The keyword arguments for the method.
:returns: The return value of the remote method.
"""
timer = Timer()
logger.debug("Calling remote method %s ..", format_call(method, *args, **kw))
self.write(dict(method=method, args=args, kw=kw))
response = self.read()
if response['success']:
logger.debug("Remote method call succeeded in %s and returned %r!", timer, response['result'])
return response['result']
else:
logger.warning("Remote method call failed after %s: %s", timer, response['error'])
raise RemoteMethodFailed(response['error'])
