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 # targetting only python-2.7 we can get rid of some older code
  38
  39 class XMLRPCTransport(xmlrpclib.Transport):
  40
  41     def __init__(self, key_file = None, cert_file = None, timeout = None):
  42         xmlrpclib.Transport.__init__(self)
  43         self.timeout=timeout
  44         self.key_file = key_file
  45         self.cert_file = cert_file
  46
  47     def make_connection(self, host):
  48         # create a HTTPS connection object from a host descriptor
  49         # host may be a string, or a (host, x509-dict) tuple
  50         host, extra_headers, x509 = self.get_host_info(host)
  51         if not ssl_needs_unverified_context:
  52             conn = HTTPSConnection(host, None, key_file = self.key_file,
  53                                    cert_file = self.cert_file)
  54         else:
  55             conn = HTTPSConnection(host, None, key_file = self.key_file,
  56                                    cert_file = self.cert_file,
  57                                    context = ssl._create_unverified_context())
  58
  59         # Some logic to deal with timeouts. It appears that some (or all) versions
  60         # of python don't set the timeout after the socket is created. We'll do it
  61         # ourselves by forcing the connection to connect, finding the socket, and
  62         # calling settimeout() on it. (tested with python 2.6)
  63         if self.timeout:
  64             if hasattr(conn, 'set_timeout'):
  65                 conn.set_timeout(self.timeout)
  66
  67             if hasattr(conn, "_conn"):
  68                 # HTTPS is a wrapper around HTTPSConnection
  69                 real_conn = conn._conn
  70             else:
  71                 real_conn = conn
  72             conn.connect()
  73             if hasattr(real_conn, "sock") and hasattr(real_conn.sock, "settimeout"):
  74                 real_conn.sock.settimeout(float(self.timeout))
  75
  76         return conn
  77
  78     def getparser(self):
  79         unmarshaller = ExceptionUnmarshaller()
  80         parser = xmlrpclib.ExpatParser(unmarshaller)
  81         return parser, unmarshaller
  82
  83 class XMLRPCServerProxy(xmlrpclib.ServerProxy):
  84     def __init__(self, url, transport, allow_none=True, verbose=False):
  85         # remember url for GetVersion
  86         # xxx not sure this is still needed as SfaServerProxy has this too
  87         self.url=url
  88         if not ssl_needs_unverified_context:
  89             xmlrpclib.ServerProxy.__init__(self, url, transport, allow_none=allow_none,
  90                                            verbose=verbose)
  91         else:
  92             xmlrpclib.ServerProxy.__init__(self, url, transport, allow_none=allow_none,
  93                                            verbose=verbose,
  94                                            context=ssl._create_unverified_context())
  95
  96     def __getattr__(self, attr):
  97         logger.debug ("xml-rpc %s method:%s" % (self.url, attr))
  98         return xmlrpclib.ServerProxy.__getattr__(self, attr)
  99
 100 ########## the object on which we can send methods that get sent over xmlrpc
 101 class SfaServerProxy:
 102
 103     def __init__ (self, url, keyfile, certfile, verbose=False, timeout=None):
 104         self.url = url
 105         self.keyfile = keyfile
 106         self.certfile = certfile
 107         self.verbose = verbose
 108         self.timeout = timeout
 109         # an instance of xmlrpclib.ServerProxy
 110         transport = XMLRPCTransport(keyfile, certfile, timeout)
 111         self.serverproxy = XMLRPCServerProxy(url, transport, allow_none=True, verbose=verbose)
 112
 113     # this is python magic to return the code to run when
 114     # SfaServerProxy receives a method call
 115     # so essentially we send the same method with identical arguments
 116     # to the server_proxy object
 117     def __getattr__(self, name):
 118         def func(*args, **kwds):
 119             return getattr(self.serverproxy, name)(*args, **kwds)
 120         return func
 121