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Wedging Basic Authentication support into python-jsonrpc

Problem: 

I want to send JSON-RPC commands to XBMC on my Raspberry Pi. The XBMC install on there will allow JSON-RPC commands from the local box or a remote box, but I've passworded it. The easiest way to talk to the RPC interface through python appears to be using the python-jsonrpc library from here. The problem is that there's no way to send a login and a password.

Investigation:

Here's some simple code that should work (if passwords weren't turned on):

from jsonrpc import ServiceProxy
s = ServiceProxy("http://127.0.0.1:8000/jsonrpc")
print s.GUI.ShowNotification("Hello!","This is a message")

if the library supported login/password combos in urls, I could do this:

from jsonrpc import ServiceProxy
s = ServiceProxy("http://user:password@127.0.0.1:8000/jsonrpc")
print s.GUI.ShowNotification("Hello!","This is a message")

..but it doesn't. If I try it that way the library fails to get the address correctly (probably it's trying to do a DNS search for the string "user:password@127.0.0.1" instead of realising that "127.0.0.1" is the machine to connect to). If I don't put in the login/password combo, it gives me a 401 authentication refused - which is fair enough.

Looking into the library I see that 1) it's a bit old (2007 was the last commit), and 2) it uses urllib in a fairly simple way. A little searching around shows me that urllib doesn't have any way of taking an authentication. Neither, critically, does it have any way of adding headers. The latest version of XBMC requires the header Content-Type: application/json in the request.

 The solution appears to be to use urllib2, which has both basic authentication support and allows you to add headers. I can modify the file python-jsonrpc/jsonrpc/proxy.py in the python-jsonrpc download, run setup.py install again, and bob's your uncle!

 ...not so fast. For some reason the Basic Authentication in urllib2 isn't working for me. I have no idea why, but it isn't. The password managers aren't triggering, so that the request gets made without authentication and fails with a 401 still.

 A little googling throws up this solution - ignore the basic auth support in urllib2, and just use the support for adding headers. Basic auth is just a header "Authorization: Basic <HASH>" ...where <HASH> is login:password base64-encoded. Modifications made, result success!

Solution:

Replacement PYTHON-JSONRPC/JSONRPC/PROXY.PY:



 """
  Copyright (c) 2007 Jan-Klaas Kollhof
  Modified 2013 Keith Lawrence

   This file is part of jsonrpc.

   jsonrpc 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 2.1 of the License, or
  (at your option) any later version.

   This software is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
  along with this software; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
"""

 import urllib2
import base64
from jsonrpc.json import dumps, loads

 class JSONRPCException(Exception):
    def __init__(self, rpcError):
        Exception.__init__(self)
        self.error = rpcError
        
class ServiceProxy(object):
    def __init__(self, serviceURL, serviceName=None, serviceUser=None, servicePassword=None):
        self.__serviceURL = serviceURL
        self.__serviceName = serviceName
        self.__serviceUser = serviceUser
        self.__servicePassword = servicePassword
        if serviceUser != None:
                self.__serviceAuth = base64.standard_b64encode('%s:%s' % (serviceUser,servicePassword))

     def __getattr__(self, name):
        if self.__serviceName != None:
            name = "%s.%s" % (self.__serviceName, name)
        return ServiceProxy(self.__serviceURL, name, self.__serviceUser, self.__servicePassword)

     def __call__(self, *args):
         postdata = dumps({'jsonrpc': '2.0', 'method': self.__serviceName, 'params': args, 'id':'jsonrpc'})

 # Comment in following two lines to add header tracing
#         opener=urllib2.build_opener(urllib2.HTTPHandler(debuglevel=1))
#         urllib2.install_opener(opener)

          request = urllib2.Request(url=self.__serviceURL)
         request.add_data(postdata)
         request.add_header('Content-Type', 'application/json')
         if self.__serviceAuth != None:
                request.add_header("Authorization", "Basic %s" % self.__serviceAuth)   

          respdata = urllib2.urlopen(request).read()
         resp = loads(respdata)
         if 'error' in resp:
             raise JSONRPCException(resp['error'])
         else:
             return resp['result']
         

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