#!/usr/bin/python
# -*- coding: utf-8 -*-
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation; either version 3, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
"Pythonic simple JSON RPC Client implementation"
__author__ = "Mariano Reingart (reingart@gmail.com)"
__copyright__ = "Copyright (C) 2011 Mariano Reingart"
__license__ = "LGPL 3.0"
__version__ = "0.04"
import urllib
from xmlrpclib import Transport, SafeTransport
from cStringIO import StringIO
import random
import sys
try:
import gluon.contrib.simplejson as json # try web2py json serializer
except ImportError:
try:
import json # try stdlib (py2.6)
except:
import simplejson as json # try external module
class JSONRPCError(RuntimeError):
"Error object for remote procedure call fail"
def __init__(self, code, message):
self.code = code
self.message = message
def __unicode__(self):
return u"%s: %s" % (self.code, self.message)
def __str__(self):
return self.__unicode__().encode("ascii","ignore")
class JSONDummyParser:
"json wrapper for xmlrpclib parser interfase"
def __init__(self):
self.buf = StringIO()
def feed(self, data):
self.buf.write(data)
def close(self):
return self.buf.getvalue()
class JSONTransportMixin:
"json wrapper for xmlrpclib transport interfase"
def send_content(self, connection, request_body):
connection.putheader("Content-Type", "application/json")
connection.putheader("Content-Length", str(len(request_body)))
connection.endheaders()
if request_body:
connection.send(request_body)
# todo: add gzip compression
def getparser(self):
# get parser and unmarshaller
parser = JSONDummyParser()
return parser, parser
class JSONTransport(JSONTransportMixin, Transport):
pass
class JSONSafeTransport(JSONTransportMixin, SafeTransport):
pass
class ServerProxy(object):
"JSON RPC Simple Client Service Proxy"
def __init__(self, uri, transport=None, encoding=None, verbose=0):
self.location = uri # server location (url)
self.trace = verbose # show debug messages
self.exceptions = True # raise errors? (JSONRPCError)
self.timeout = None
self.json_request = self.json_response = ''
type, uri = urllib.splittype(uri)
if type not in ("http", "https"):
raise IOError, "unsupported JSON-RPC protocol"
self.__host, self.__handler = urllib.splithost(uri)
if transport is None:
if type == "https":
transport = JSONSafeTransport()
else:
transport = JSONTransport()
self.__transport = transport
self.__encoding = encoding
self.__verbose = verbose
def __getattr__(self, attr):
"pseudo method that can be called"
return lambda *args: self.call(attr, *args)
def call(self, method, *args):
"JSON RPC communication (method invocation)"
# build data sent to the service
request_id = random.randint(0, sys.maxint)
data = {'id': request_id, 'method': method, 'params': args, }
request = json.dumps(data)
# make HTTP request (retry if connection is lost)
response = self.__transport.request(
self.__host,
self.__handler,
request,
verbose=self.__verbose
)
# store plain request and response for further debugging
self.json_request = request
self.json_response = response
# parse json data coming from service
# {'version': '1.1', 'id': id, 'result': result, 'error': None}
response = json.loads(response)
if response['id'] != request_id:
raise JSONRPCError(0, "JSON Request ID != Response ID")
self.error = response.get('error', {})
if self.error and self.exceptions:
raise JSONRPCError(self.error.get('code', 0), self.error.get('message', ''))
return response.get('result')
if __name__ == "__main__":
# basic tests:
location = "http://www.web2py.com.ar/webservices/sample/call/jsonrpc"
client = ServerProxy(location, verbose='--verbose' in sys.argv,)
print client.add(1, 2)