513 lines
17 KiB
Python
513 lines
17 KiB
Python
"""Simple XML-RPC Server.
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This module can be used to create simple XML-RPC servers
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by creating a server and either installing functions, a
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class instance, or by extending the SimpleXMLRPCServer
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class.
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It can also be used to handle XML-RPC requests in a CGI
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environment using CGIXMLRPCRequestHandler.
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A list of possible usage patterns follows:
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1. Install functions:
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server = SimpleXMLRPCServer(("localhost", 8000))
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server.register_function(pow)
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server.register_function(lambda x,y: x+y, 'add')
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server.serve_forever()
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2. Install an instance:
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class MyFuncs:
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def __init__(self):
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# make all of the string functions available through
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# string.func_name
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import string
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self.string = string
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def _listMethods(self):
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# implement this method so that system.listMethods
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# knows to advertise the strings methods
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return list_public_methods(self) + \
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['string.' + method for method in list_public_methods(self.string)]
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def pow(self, x, y): return pow(x, y)
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def add(self, x, y) : return x + y
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server = SimpleXMLRPCServer(("localhost", 8000))
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server.register_introspection_functions()
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server.register_instance(MyFuncs())
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server.serve_forever()
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3. Install an instance with custom dispatch method:
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class Math:
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def _listMethods(self):
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# this method must be present for system.listMethods
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# to work
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return ['add', 'pow']
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def _methodHelp(self, method):
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# this method must be present for system.methodHelp
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# to work
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if method == 'add':
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return "add(2,3) => 5"
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elif method == 'pow':
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return "pow(x, y[, z]) => number"
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else:
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# By convention, return empty
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# string if no help is available
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return ""
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def _dispatch(self, method, params):
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if method == 'pow':
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return pow(*params)
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elif method == 'add':
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return params[0] + params[1]
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else:
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raise 'bad method'
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server = SimpleXMLRPCServer(("localhost", 8000))
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server.register_introspection_functions()
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server.register_instance(Math())
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server.serve_forever()
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4. Subclass SimpleXMLRPCServer:
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class MathServer(SimpleXMLRPCServer):
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def _dispatch(self, method, params):
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try:
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# We are forcing the 'export_' prefix on methods that are
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# callable through XML-RPC to prevent potential security
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# problems
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func = getattr(self, 'export_' + method)
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except AttributeError:
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raise Exception('method "%s" is not supported' % method)
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else:
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return func(*params)
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def export_add(self, x, y):
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return x + y
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server = MathServer(("localhost", 8000))
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server.serve_forever()
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5. CGI script:
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server = CGIXMLRPCRequestHandler()
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server.register_function(pow)
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server.handle_request()
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"""
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# Written by Brian Quinlan (brian@sweetapp.com).
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# Based on code written by Fredrik Lundh.
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import xmlrpclib
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from xmlrpclib import Fault
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import SocketServer
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import BaseHTTPServer
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import sys
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import os
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def resolve_dotted_attribute(obj, attr):
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"""resolve_dotted_attribute(a, 'b.c.d') => a.b.c.d
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Resolves a dotted attribute name to an object. Raises
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an AttributeError if any attribute in the chain starts with a '_'.
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"""
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for i in attr.split('.'):
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if i.startswith('_'):
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raise AttributeError(
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'attempt to access private attribute "%s"' % i
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)
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else:
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obj = getattr(obj,i)
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return obj
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def list_public_methods(obj):
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"""Returns a list of attribute strings, found in the specified
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object, which represent callable attributes"""
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return [member for member in dir(obj)
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if not member.startswith('_') and
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callable(getattr(obj, member))]
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def remove_duplicates(lst):
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"""remove_duplicates([2,2,2,1,3,3]) => [3,1,2]
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Returns a copy of a list without duplicates. Every list
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item must be hashable and the order of the items in the
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resulting list is not defined.
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"""
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u = {}
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for x in lst:
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u[x] = 1
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return u.keys()
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class SimpleXMLRPCDispatcher:
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"""Mix-in class that dispatches XML-RPC requests.
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This class is used to register XML-RPC method handlers
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and then to dispatch them. There should never be any
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reason to instantiate this class directly.
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"""
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def __init__(self):
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self.funcs = {}
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self.instance = None
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def register_instance(self, instance):
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"""Registers an instance to respond to XML-RPC requests.
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Only one instance can be installed at a time.
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If the registered instance has a _dispatch method then that
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method will be called with the name of the XML-RPC method and
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it's parameters as a tuple
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e.g. instance._dispatch('add',(2,3))
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If the registered instance does not have a _dispatch method
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then the instance will be searched to find a matching method
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and, if found, will be called. Methods beginning with an '_'
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are considered private and will not be called by
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SimpleXMLRPCServer.
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If a registered function matches a XML-RPC request, then it
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will be called instead of the registered instance.
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"""
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self.instance = instance
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def register_function(self, function, name = None):
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"""Registers a function to respond to XML-RPC requests.
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The optional name argument can be used to set a Unicode name
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for the function.
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"""
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if name is None:
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name = function.__name__
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self.funcs[name] = function
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def register_introspection_functions(self):
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"""Registers the XML-RPC introspection methods in the system
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namespace.
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see http://xmlrpc.usefulinc.com/doc/reserved.html
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"""
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self.funcs.update({'system.listMethods' : self.system_listMethods,
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'system.methodSignature' : self.system_methodSignature,
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'system.methodHelp' : self.system_methodHelp})
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def register_multicall_functions(self):
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"""Registers the XML-RPC multicall method in the system
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namespace.
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see http://www.xmlrpc.com/discuss/msgReader$1208"""
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self.funcs.update({'system.multicall' : self.system_multicall})
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def _marshaled_dispatch(self, data, dispatch_method = None):
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"""Dispatches an XML-RPC method from marshalled (XML) data.
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XML-RPC methods are dispatched from the marshalled (XML) data
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using the _dispatch method and the result is returned as
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marshalled data. For backwards compatibility, a dispatch
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function can be provided as an argument (see comment in
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SimpleXMLRPCRequestHandler.do_POST) but overriding the
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existing method through subclassing is the prefered means
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of changing method dispatch behavior.
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"""
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params, method = xmlrpclib.loads(data)
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# generate response
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try:
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if dispatch_method is not None:
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response = dispatch_method(method, params)
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else:
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response = self._dispatch(method, params)
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# wrap response in a singleton tuple
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response = (response,)
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response = xmlrpclib.dumps(response, methodresponse=1)
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except Fault, fault:
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response = xmlrpclib.dumps(fault)
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except:
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# report exception back to server
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response = xmlrpclib.dumps(
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xmlrpclib.Fault(1, "%s:%s" % (sys.exc_type, sys.exc_value))
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)
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return response
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def system_listMethods(self):
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"""system.listMethods() => ['add', 'subtract', 'multiple']
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Returns a list of the methods supported by the server."""
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methods = self.funcs.keys()
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if self.instance is not None:
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# Instance can implement _listMethod to return a list of
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# methods
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if hasattr(self.instance, '_listMethods'):
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methods = remove_duplicates(
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methods + self.instance._listMethods()
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)
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# if the instance has a _dispatch method then we
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# don't have enough information to provide a list
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# of methods
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elif not hasattr(self.instance, '_dispatch'):
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methods = remove_duplicates(
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methods + list_public_methods(self.instance)
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)
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methods.sort()
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return methods
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def system_methodSignature(self, method_name):
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"""system.methodSignature('add') => [double, int, int]
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Returns a list describing the signiture of the method. In the
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above example, the add method takes two integers as arguments
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and returns a double result.
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This server does NOT support system.methodSignature."""
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# See http://xmlrpc.usefulinc.com/doc/sysmethodsig.html
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return 'signatures not supported'
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def system_methodHelp(self, method_name):
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"""system.methodHelp('add') => "Adds two integers together"
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Returns a string containing documentation for the specified method."""
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method = None
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if self.funcs.has_key(method_name):
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method = self.funcs[method_name]
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elif self.instance is not None:
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# Instance can implement _methodHelp to return help for a method
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if hasattr(self.instance, '_methodHelp'):
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return self.instance._methodHelp(method_name)
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# if the instance has a _dispatch method then we
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# don't have enough information to provide help
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elif not hasattr(self.instance, '_dispatch'):
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try:
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method = resolve_dotted_attribute(
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self.instance,
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method_name
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)
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except AttributeError:
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pass
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# Note that we aren't checking that the method actually
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# be a callable object of some kind
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if method is None:
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return ""
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else:
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import pydoc
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return pydoc.getdoc(method)
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def system_multicall(self, call_list):
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"""system.multicall([{'methodName': 'add', 'params': [2, 2]}, ...]) => \
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[[4], ...]
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Allows the caller to package multiple XML-RPC calls into a single
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request.
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See http://www.xmlrpc.com/discuss/msgReader$1208
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"""
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results = []
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for call in call_list:
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method_name = call['methodName']
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params = call['params']
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try:
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# XXX A marshalling error in any response will fail the entire
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# multicall. If someone cares they should fix this.
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results.append([self._dispatch(method_name, params)])
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except Fault, fault:
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results.append(
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{'faultCode' : fault.faultCode,
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'faultString' : fault.faultString}
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)
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except:
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results.append(
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{'faultCode' : 1,
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'faultString' : "%s:%s" % (sys.exc_type, sys.exc_value)}
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)
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return results
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def _dispatch(self, method, params):
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"""Dispatches the XML-RPC method.
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XML-RPC calls are forwarded to a registered function that
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matches the called XML-RPC method name. If no such function
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exists then the call is forwarded to the registered instance,
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if available.
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If the registered instance has a _dispatch method then that
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method will be called with the name of the XML-RPC method and
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it's parameters as a tuple
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e.g. instance._dispatch('add',(2,3))
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If the registered instance does not have a _dispatch method
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then the instance will be searched to find a matching method
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and, if found, will be called.
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Methods beginning with an '_' are considered private and will
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not be called.
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"""
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func = None
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try:
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# check to see if a matching function has been registered
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func = self.funcs[method]
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except KeyError:
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if self.instance is not None:
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# check for a _dispatch method
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if hasattr(self.instance, '_dispatch'):
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return self.instance._dispatch(method, params)
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else:
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# call instance method directly
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try:
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func = resolve_dotted_attribute(
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self.instance,
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method
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)
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except AttributeError:
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pass
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if func is not None:
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return func(*params)
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else:
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raise Exception('method "%s" is not supported' % method)
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class SimpleXMLRPCRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
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"""Simple XML-RPC request handler class.
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Handles all HTTP POST requests and attempts to decode them as
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XML-RPC requests.
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"""
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def do_POST(self):
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"""Handles the HTTP POST request.
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Attempts to interpret all HTTP POST requests as XML-RPC calls,
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which are forwarded to the server's _dispatch method for handling.
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"""
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try:
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# get arguments
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data = self.rfile.read(int(self.headers["content-length"]))
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# In previous versions of SimpleXMLRPCServer, _dispatch
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# could be overridden in this class, instead of in
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# SimpleXMLRPCDispatcher. To maintain backwards compatibility,
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# check to see if a subclass implements _dispatch and dispatch
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# using that method if present.
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response = self.server._marshaled_dispatch(
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data, getattr(self, '_dispatch', None)
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)
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except: # This should only happen if the module is buggy
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# internal error, report as HTTP server error
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self.send_response(500)
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self.end_headers()
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else:
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# got a valid XML RPC response
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self.send_response(200)
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self.send_header("Content-type", "text/xml")
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self.send_header("Content-length", str(len(response)))
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self.end_headers()
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self.wfile.write(response)
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# shut down the connection
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self.wfile.flush()
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self.connection.shutdown(1)
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def log_request(self, code='-', size='-'):
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"""Selectively log an accepted request."""
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if self.server.logRequests:
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BaseHTTPServer.BaseHTTPRequestHandler.log_request(self, code, size)
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class SimpleXMLRPCServer(SocketServer.TCPServer,
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SimpleXMLRPCDispatcher):
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"""Simple XML-RPC server.
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Simple XML-RPC server that allows functions and a single instance
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to be installed to handle requests. The default implementation
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attempts to dispatch XML-RPC calls to the functions or instance
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installed in the server. Override the _dispatch method inhereted
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from SimpleXMLRPCDispatcher to change this behavior.
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"""
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def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
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logRequests=1):
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self.logRequests = logRequests
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SimpleXMLRPCDispatcher.__init__(self)
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SocketServer.TCPServer.__init__(self, addr, requestHandler)
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class CGIXMLRPCRequestHandler(SimpleXMLRPCDispatcher):
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"""Simple handler for XML-RPC data passed through CGI."""
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def __init__(self):
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SimpleXMLRPCDispatcher.__init__(self)
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def handle_xmlrpc(self, request_text):
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"""Handle a single XML-RPC request"""
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response = self._marshaled_dispatch(request_text)
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print 'Content-Type: text/xml'
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print 'Content-Length: %d' % len(response)
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print
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sys.stdout.write(response)
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def handle_get(self):
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"""Handle a single HTTP GET request.
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Default implementation indicates an error because
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XML-RPC uses the POST method.
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"""
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code = 400
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message, explain = \
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BaseHTTPServer.BaseHTTPRequestHandler.responses[code]
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response = BaseHTTPServer.DEFAULT_ERROR_MESSAGE % \
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{
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'code' : code,
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'message' : message,
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'explain' : explain
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}
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print 'Status: %d %s' % (code, message)
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print 'Content-Type: text/html'
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print 'Content-Length: %d' % len(response)
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print
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sys.stdout.write(response)
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def handle_request(self, request_text = None):
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"""Handle a single XML-RPC request passed through a CGI post method.
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If no XML data is given then it is read from stdin. The resulting
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XML-RPC response is printed to stdout along with the correct HTTP
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headers.
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"""
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if request_text is None and \
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os.environ.get('REQUEST_METHOD', None) == 'GET':
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self.handle_get()
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else:
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# POST data is normally available through stdin
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if request_text is None:
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request_text = sys.stdin.read()
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self.handle_xmlrpc(request_text)
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if __name__ == '__main__':
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server = SimpleXMLRPCServer(("localhost", 8000))
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server.register_function(pow)
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server.register_function(lambda x,y: x+y, 'add')
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server.serve_forever()
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