json_client.py

import json, socket, itertools

class JSONClient(object):
    socket = None
    def __init__(self, addr):
        self.socket = socket.create_connection(addr)
        self.id_counter = itertools.count()
    def __del__(self):
        if self.socket is not None:
            self.socket.close()
    def call(self, name, *params):
        request = dict(id=next(self.id_counter),
                    params=list(params),
                    method=name)
        self.socket.sendall(json.dumps(request).encode())
        # This must loop if resp is bigger than 4K
        buffer = ''
        data = True
        while data:
            data = self.socket.recv(4096)
            buffer += data
            if len(data) < 4096: break
        response = json.loads(buffer.decode())
        if response.get('id') != request.get('id'):
            raise Exception("expected id=%s, received id=%s: %s"
                    %(request.get('id'), response.get('id'),
                        response.get('error')))
        if response.get('error') is not None:
            raise Exception(response.get('error'))
        return response.get('result')