sfa/client/sfaserverproxy.py

   1 # XMLRPC-specific code for SFA Client
   2
   3 # starting with 2.7.9 we need to turn off server verification
   4 import ssl
   5 ssl_needs_unverified_context = hasattr(ssl, '_create_unverified_context')
   6
   7 import xmlrpclib
   8 from httplib import HTTPS, HTTPSConnection
   9
  10 try:
  11     from sfa.util.sfalogging import logger
  12 except:
  13     import logging
  14     logger=logging.getLogger('sfaserverproxy')
  15
  16 ##
  17 # ServerException, ExceptionUnmarshaller
  18 #
  19 # Used to convert server exception strings back to an exception.
  20 #    from usenet, Raghuram Devarakonda
  21
  22 class ServerException(Exception):
  23     pass
  24
  25 class ExceptionUnmarshaller(xmlrpclib.Unmarshaller):
  26     def close(self):
  27         try:
  28             return xmlrpclib.Unmarshaller.close(self)
  29         except xmlrpclib.Fault, e:
  30             raise ServerException(e.faultString)
  31
  32 ##
  33 # XMLRPCTransport
  34 #
  35 # A transport for XMLRPC that works on top of HTTPS
  36
  37 # python 2.7 xmlrpclib has changed its internal code
  38 # it now calls 'getresponse' on the obj returned by make_connection
  39 # while it used to call 'getreply'
  40 # regardless of the version, httplib.HTTPS does implement getreply,
  41 # while httplib.HTTPSConnection has getresponse
  42 # so we create a dummy instance to check what's expected
  43 need_HTTPSConnection=hasattr(xmlrpclib.Transport().make_connection('localhost'),'getresponse')
  44
  45 class XMLRPCTransport(xmlrpclib.Transport):
  46
  47     def __init__(self, key_file=None, cert_file=None, timeout=None):
  48         xmlrpclib.Transport.__init__(self)
  49         self.timeout=timeout
  50         self.key_file = key_file
  51         self.cert_file = cert_file
  52
  53     def make_connection(self, host):
  54         # create a HTTPS connection object from a host descriptor
  55         # host may be a string, or a (host, x509-dict) tuple
  56         host, extra_headers, x509 = self.get_host_info(host)
  57         if need_HTTPSConnection:
  58             if not ssl_needs_unverified_context:
  59                 conn = HTTPSConnection(host, None, key_file = self.key_file,
  60                                        cert_file = self.cert_file)
  61             else:
  62                 conn = HTTPSConnection(host, None, key_file = self.key_file,
  63                                        cert_file = self.cert_file,
  64                                        context = ssl._create_unverified_context())
  65         else:
  66             conn = HTTPS(host, None, key_file=self.key_file, cert_file=self.cert_file)
  67
  68         # Some logic to deal with timeouts. It appears that some (or all) versions
  69         # of python don't set the timeout after the socket is created. We'll do it
  70         # ourselves by forcing the connection to connect, finding the socket, and
  71         # calling settimeout() on it. (tested with python 2.6)
  72         if self.timeout:
  73             if hasattr(conn, 'set_timeout'):
  74                 conn.set_timeout(self.timeout)
  75
  76             if hasattr(conn, "_conn"):
  77                 # HTTPS is a wrapper around HTTPSConnection
  78                 real_conn = conn._conn
  79             else:
  80                 real_conn = conn
  81             conn.connect()
  82             if hasattr(real_conn, "sock") and hasattr(real_conn.sock, "settimeout"):
  83                 real_conn.sock.settimeout(float(self.timeout))
  84
  85         return conn
  86
  87     def getparser(self):
  88         unmarshaller = ExceptionUnmarshaller()
  89         parser = xmlrpclib.ExpatParser(unmarshaller)
  90         return parser, unmarshaller
  91
  92 class XMLRPCServerProxy(xmlrpclib.ServerProxy):
  93     def __init__(self, url, transport, allow_none=True, verbose=False):
  94         # remember url for GetVersion
  95         # xxx not sure this is still needed as SfaServerProxy has this too
  96         self.url=url
  97         if not ssl_needs_unverified_context:
  98             xmlrpclib.ServerProxy.__init__(self, url, transport, allow_none=allow_none,
  99                                            verbose=verbose)
 100         else:
 101             xmlrpclib.ServerProxy.__init__(self, url, transport, allow_none=allow_none,
 102                                            verbose=verbose,
 103                                            context=ssl._create_unverified_context())
 104
 105     def __getattr__(self, attr):
 106         logger.debug ("xml-rpc %s method:%s" % (self.url, attr))
 107         return xmlrpclib.ServerProxy.__getattr__(self, attr)
 108
 109 ########## the object on which we can send methods that get sent over xmlrpc
 110 class SfaServerProxy:
 111
 112     def __init__ (self, url, keyfile, certfile, verbose=False, timeout=None):
 113         self.url=url
 114         self.keyfile=keyfile
 115         self.certfile=certfile
 116         self.verbose=verbose
 117         self.timeout=timeout
 118         # an instance of xmlrpclib.ServerProxy
 119         transport = XMLRPCTransport(keyfile, certfile, timeout)
 120         self.serverproxy = XMLRPCServerProxy(url, transport, allow_none=True, verbose=verbose)
 121
 122     # this is python magic to return the code to run when
 123     # SfaServerProxy receives a method call
 124     # so essentially we send the same method with identical arguments
 125     # to the server_proxy object
 126     def __getattr__(self, name):
 127         def func(*args, **kwds):
 128             return getattr(self.serverproxy, name)(*args, **kwds)
 129         return func
 130