json-rpc client

gistfile1.py

"""
A command-line client. Run `twistd -ny jsonrpc_dev.py` first before running this.
"""

# TODO:
# 1) pretty-print json
# 2) take hostname and port as optional parameters

import sys
from twisted.internet import reactor, protocol
from twisted.internet.endpoints import TCP4ClientEndpoint

class EchoClient(protocol.Protocol):
    """Once connected, send a message, then print the result."""
    def sendMessage(self, method, params):
        rq = '{{"jsonrpc":"2.0","id":"foo123","method":"{}","params":{}}}'.format(method, params)
        print "sending request:\n", rq
        self.transport.write(rq)

    def dataReceived(self, data):
        "As soon as any data is received, write it back."
        print "Server said:\n", data

class EchoFactory(protocol.ClientFactory):
    def buildProtocol(self, addr):
        return EchoClient()

def sendAndQuit(p, method, params):
    p.sendMessage(method, params)
    reactor.callLater(2, p.transport.loseConnection)
    reactor.callLater(2, reactor.stop)

# this connects the protocol to a server runing on port 8000
def main():
    if (len(sys.argv) < 3):
        print """Usage: `python client.py method parameters`
example: `python client.py getEcho '{"foo":"bar"}'`
        """
        return

    method = sys.argv[1]
    params = sys.argv[2]

    point = TCP4ClientEndpoint(reactor, "localhost", 7000)
    d = point.connect(EchoFactory())
    d.addCallback(sendAndQuit, method, params)
    reactor.run()

# this only runs if the module was *not* imported
if __name__ == '__main__':
    main()