21.27. xmlrpc.server — Basic XML-RPC servers

Source code: Lib/xmlrpc/server.py

The xmlrpc.server module provides a basic server framework for XML-RPC servers written in Python. Servers can either be free standing, using SimpleXMLRPCServer, or embedded in a CGI environment, using CGIXMLRPCRequestHandler.

Warning

The xmlrpc.server module is not secure against maliciously constructed data. If you need to parse untrusted or unauthenticated data see XML vulnerabilities.

class xmlrpc.server.SimpleXMLRPCServer(addr, requestHandler=SimpleXMLRPCRequestHandler, logRequests=True, allow_none=False, encoding=None, bind_and_activate=True, use_builtin_types=False)

Create a new server instance. This class provides methods for registration of functions that can be called by the XML-RPC protocol. The requestHandler parameter should be a factory for request handler instances; it defaults to SimpleXMLRPCRequestHandler. The addr and requestHandler parameters are passed to the socketserver.TCPServer constructor. If logRequests is true (the default), requests will be logged; setting this parameter to false will turn off logging. The allow_none and encoding parameters are passed on to xmlrpc.client and control the XML-RPC responses that will be returned from the server. The bind_and_activate parameter controls whether server_bind() and server_activate() are called immediately by the constructor; it defaults to true. Setting it to false allows code to manipulate the allow_reuse_address class variable before the address is bound. The use_builtin_types parameter is passed to the loads() function and controls which types are processed when date/times values or binary data are received; it defaults to false.

Changed in version 3.3: The use_builtin_types flag was added.

class xmlrpc.server.CGIXMLRPCRequestHandler(allow_none=False, encoding=None, use_builtin_types=False)

Create a new instance to handle XML-RPC requests in a CGI environment. The allow_none and encoding parameters are passed on to xmlrpc.client and control the XML-RPC responses that will be returned from the server. The use_builtin_types parameter is passed to the loads() function and controls which types are processed when date/times values or binary data are received; it defaults to false.

Changed in version 3.3: The use_builtin_types flag was added.

class xmlrpc.server.SimpleXMLRPCRequestHandler

Create a new request handler instance. This request handler supports POST requests and modifies logging so that the logRequests parameter to the SimpleXMLRPCServer constructor parameter is honored.

21.27.1. SimpleXMLRPCServer Objects

The SimpleXMLRPCServer class is based on socketserver.TCPServer and provides a means of creating simple, stand alone XML-RPC servers.

SimpleXMLRPCServer.register_function(function, name=None)

Register a function that can respond to XML-RPC requests. If name is given, it will be the method name associated with function, otherwise function.__name__ will be used. name can be either a normal or Unicode string, and may contain characters not legal in Python identifiers, including the period character.

SimpleXMLRPCServer.register_instance(instance, allow_dotted_names=False)

Register an object which is used to expose method names which have not been registered using register_function(). If instance contains a _dispatch() method, it is called with the requested method name and the parameters from the request. Its API is def _dispatch(self, method, params) (note that params does not represent a variable argument list). If it calls an underlying function to perform its task, that function is called as func(*params), expanding the parameter list. The return value from _dispatch() is returned to the client as the result. If instance does not have a _dispatch() method, it is searched for an attribute matching the name of the requested method.

If the optional allow_dotted_names argument is true and the instance does not have a _dispatch() method, then if the requested method name contains periods, each component of the method name is searched for individually, with the effect that a simple hierarchical search is performed. The value found from this search is then called with the parameters from the request, and the return value is passed back to the client.

Warning

Enabling the allow_dotted_names option allows intruders to access your module’s global variables and may allow intruders to execute arbitrary code on your machine. Only use this option on a secure, closed network.

SimpleXMLRPCServer.register_introspection_functions()

Registers the XML-RPC introspection functions system.listMethods, system.methodHelp and system.methodSignature.

SimpleXMLRPCServer.register_multicall_functions()

Registers the XML-RPC multicall function system.multicall.

SimpleXMLRPCRequestHandler.rpc_paths

An attribute value that must be a tuple listing valid path portions of the URL for receiving XML-RPC requests. Requests posted to other paths will result in a 404 “no such page” HTTP error. If this tuple is empty, all paths will be considered valid. The default value is ('/', '/RPC2').

21.27.1.1. SimpleXMLRPCServer Example

Server code:

from xmlrpc.server import SimpleXMLRPCServer
from xmlrpc.server import SimpleXMLRPCRequestHandler

# Restrict to a particular path.
class RequestHandler(SimpleXMLRPCRequestHandler):
    rpc_paths = ('/RPC2',)

# Create server
server = SimpleXMLRPCServer(("localhost", 8000),
                            requestHandler=RequestHandler)
server.register_introspection_functions()

# Register pow() function; this will use the value of
# pow.__name__ as the name, which is just 'pow'.
server.register_function(pow)

# Register a function under a different name
def adder_function(x,y):
    return x + y
server.register_function(adder_function, 'add')

# Register an instance; all the methods of the instance are
# published as XML-RPC methods (in this case, just 'mul').
class MyFuncs:
    def mul(self, x, y):
        return x * y

server.register_instance(MyFuncs())

# Run the server's main loop
server.serve_forever()

The following client code will call the methods made available by the preceding server:

import xmlrpc.client

s = xmlrpc.client.ServerProxy('http://localhost:8000')
print(s.pow(2,3))  # Returns 2**3 = 8
print(s.add(2,3))  # Returns 5
print(s.mul(5,2))  # Returns 5*2 = 10

# Print list of available methods
print(s.system.listMethods())

The following example included in the Lib/xmlrpc/server.py module shows a server allowing dotted names and registering a multicall function.

Warning

Enabling the allow_dotted_names option allows intruders to access your module’s global variables and may allow intruders to execute arbitrary code on your machine. Only use this example only within a secure, closed network.

import datetime

class ExampleService:
    def getData(self):
        return '42'

    class currentTime:
        @staticmethod
        def getCurrentTime():
            return datetime.datetime.now()

server = SimpleXMLRPCServer(("localhost", 8000))
server.register_function(pow)
server.register_function(lambda x,y: x+y, 'add')
server.register_instance(ExampleService(), allow_dotted_names=True)
server.register_multicall_functions()
print('Serving XML-RPC on localhost port 8000')
try:
    server.serve_forever()
except KeyboardInterrupt:
    print("\nKeyboard interrupt received, exiting.")
    server.server_close()
    sys.exit(0)

This ExampleService demo can be invoked from the command line:

python -m xmlrpc.server

The client that interacts with the above server is included in Lib/xmlrpc/client.py:

server = ServerProxy("http://localhost:8000")

try:
    print(server.currentTime.getCurrentTime())
except Error as v:
    print("ERROR", v)

multi = MultiCall(server)
multi.getData()
multi.pow(2,9)
multi.add(1,2)
try:
    for response in multi():
        print(response)
except Error as v:
    print("ERROR", v)

This client which interacts with the demo XMLRPC server can be invoked as:

python -m xmlrpc.client

21.27.2. CGIXMLRPCRequestHandler

The CGIXMLRPCRequestHandler class can be used to handle XML-RPC requests sent to Python CGI scripts.

CGIXMLRPCRequestHandler.register_function(function, name=None)

Register a function that can respond to XML-RPC requests. If name is given, it will be the method name associated with function, otherwise function.__name__ will be used. name can be either a normal or Unicode string, and may contain characters not legal in Python identifiers, including the period character.

CGIXMLRPCRequestHandler.register_instance(instance)

Register an object which is used to expose method names which have not been registered using register_function(). If instance contains a _dispatch() method, it is called with the requested method name and the parameters from the request; the return value is returned to the client as the result. If instance does not have a _dispatch() method, it is searched for an attribute matching the name of the requested method; if the requested method name contains periods, each component of the method name is searched for individually, with the effect that a simple hierarchical search is performed. The value found from this search is then called with the parameters from the request, and the return value is passed back to the client.

CGIXMLRPCRequestHandler.register_introspection_functions()

Register the XML-RPC introspection functions system.listMethods, system.methodHelp and system.methodSignature.

CGIXMLRPCRequestHandler.register_multicall_functions()

Register the XML-RPC multicall function system.multicall.

CGIXMLRPCRequestHandler.handle_request(request_text=None)

Handle an XML-RPC request. If request_text is given, it should be the POST data provided by the HTTP server, otherwise the contents of stdin will be used.

Example:

class MyFuncs:
    def mul(self, x, y):
        return x * y


handler = CGIXMLRPCRequestHandler()
handler.register_function(pow)
handler.register_function(lambda x,y: x+y, 'add')
handler.register_introspection_functions()
handler.register_instance(MyFuncs())
handler.handle_request()

21.27.3. Documenting XMLRPC server

These classes extend the above classes to serve HTML documentation in response to HTTP GET requests. Servers can either be free standing, using DocXMLRPCServer, or embedded in a CGI environment, using DocCGIXMLRPCRequestHandler.

class xmlrpc.server.DocXMLRPCServer(addr, requestHandler=DocXMLRPCRequestHandler, logRequests=True, allow_none=False, encoding=None, bind_and_activate=True, use_builtin_types=True)

Create a new server instance. All parameters have the same meaning as for SimpleXMLRPCServer; requestHandler defaults to DocXMLRPCRequestHandler.

Changed in version 3.3: The use_builtin_types flag was added.

class xmlrpc.server.DocCGIXMLRPCRequestHandler

Create a new instance to handle XML-RPC requests in a CGI environment.

class xmlrpc.server.DocXMLRPCRequestHandler

Create a new request handler instance. This request handler supports XML-RPC POST requests, documentation GET requests, and modifies logging so that the logRequests parameter to the DocXMLRPCServer constructor parameter is honored.

21.27.4. DocXMLRPCServer Objects

The DocXMLRPCServer class is derived from SimpleXMLRPCServer and provides a means of creating self-documenting, stand alone XML-RPC servers. HTTP POST requests are handled as XML-RPC method calls. HTTP GET requests are handled by generating pydoc-style HTML documentation. This allows a server to provide its own web-based documentation.

DocXMLRPCServer.set_server_title(server_title)

Set the title used in the generated HTML documentation. This title will be used inside the HTML “title” element.

DocXMLRPCServer.set_server_name(server_name)

Set the name used in the generated HTML documentation. This name will appear at the top of the generated documentation inside a “h1” element.

DocXMLRPCServer.set_server_documentation(server_documentation)

Set the description used in the generated HTML documentation. This description will appear as a paragraph, below the server name, in the documentation.

21.27.5. DocCGIXMLRPCRequestHandler

The DocCGIXMLRPCRequestHandler class is derived from CGIXMLRPCRequestHandler and provides a means of creating self-documenting, XML-RPC CGI scripts. HTTP POST requests are handled as XML-RPC method calls. HTTP GET requests are handled by generating pydoc-style HTML documentation. This allows a server to provide its own web-based documentation.

DocCGIXMLRPCRequestHandler.set_server_title(server_title)

Set the title used in the generated HTML documentation. This title will be used inside the HTML “title” element.

DocCGIXMLRPCRequestHandler.set_server_name(server_name)

Set the name used in the generated HTML documentation. This name will appear at the top of the generated documentation inside a “h1” element.

DocCGIXMLRPCRequestHandler.set_server_documentation(server_documentation)

Set the description used in the generated HTML documentation. This description will appear as a paragraph, below the server name, in the documentation.