Lib/xmlrpc/server.py

"""XML-RPC Servers.

This module can be used to create simple XML-RPC servers
by creating a server and either installing functions, a
class instance, or by extending the SimpleXMLRPCServer
class.

It can also be used to handle XML-RPC requests in a CGI
environment using CGIXMLRPCRequestHandler.

The Doc* classes can be used to create XML-RPC servers that
serve pydoc-style documentation in response to HTTP
GET requests. This documentation is dynamically generated
based on the functions and methods registered with the
server.

A list of possible usage patterns follows:

1. Install functions:

server = SimpleXMLRPCServer(("localhost", 8000))
server.register_function(pow)
server.register_function(lambda x,y: x+y, 'add')
server.serve_forever()

2. Install an instance:

class MyFuncs:
    def __init__(self):
        # make all of the sys functions available through sys.func_name
        import sys
        self.sys = sys
    def _listMethods(self):
        # implement this method so that system.listMethods
        # knows to advertise the sys methods
        return list_public_methods(self) + \
                ['sys.' + method for method in list_public_methods(self.sys)]
    def pow(self, x, y): return pow(x, y)
    def add(self, x, y) : return x + y

server = SimpleXMLRPCServer(("localhost", 8000))
server.register_introspection_functions()
server.register_instance(MyFuncs())
server.serve_forever()

3. Install an instance with custom dispatch method:

class Math:
    def _listMethods(self):
        # this method must be present for system.listMethods
        # to work
        return ['add', 'pow']
    def _methodHelp(self, method):
        # this method must be present for system.methodHelp
        # to work
        if method == 'add':
            return "add(2,3) => 5"
        elif method == 'pow':
            return "pow(x, y[, z]) => number"
        else:
            # By convention, return empty
            # string if no help is available
            return ""
    def _dispatch(self, method, params):
        if method == 'pow':
            return pow(*params)
        elif method == 'add':
            return params[0] + params[1]
        else:
            raise 'bad method'

server = SimpleXMLRPCServer(("localhost", 8000))
server.register_introspection_functions()
server.register_instance(Math())
server.serve_forever()

4. Subclass SimpleXMLRPCServer:

class MathServer(SimpleXMLRPCServer):
    def _dispatch(self, method, params):
        try:
            # We are forcing the 'export_' prefix on methods that are
            # callable through XML-RPC to prevent potential security
            # problems
            func = getattr(self, 'export_' + method)
        except AttributeError:
            raise Exception('method "%s" is not supported' % method)
        else:
            return func(*params)

    def export_add(self, x, y):
        return x + y

server = MathServer(("localhost", 8000))
server.serve_forever()

5. CGI script:

server = CGIXMLRPCRequestHandler()
server.register_function(pow)
server.handle_request()
"""

# Written by Brian Quinlan (brian@sweetapp.com).
# Based on code written by Fredrik Lundh.

from xmlrpc.client import Fault, dumps, loads
import socketserver
import BaseHTTPServer
import sys
import os
import re
import pydoc
import inspect
import traceback
try:
    import fcntl
except ImportError:
    fcntl = None

def resolve_dotted_attribute(obj, attr, allow_dotted_names=True):
    """resolve_dotted_attribute(a, 'b.c.d') => a.b.c.d

    Resolves a dotted attribute name to an object.  Raises
    an AttributeError if any attribute in the chain starts with a '_'.

    If the optional allow_dotted_names argument is false, dots are not
    supported and this function operates similar to getattr(obj, attr).
    """

    if allow_dotted_names:
        attrs = attr.split('.')
    else:
        attrs = [attr]

    for i in attrs:
        if i.startswith('_'):
            raise AttributeError(
                'attempt to access private attribute "%s"' % i
                )
        else:
            obj = getattr(obj,i)
    return obj

def list_public_methods(obj):
    """Returns a list of attribute strings, found in the specified
    object, which represent callable attributes"""

    return [member for member in dir(obj)
                if not member.startswith('_') and
                    hasattr(getattr(obj, member), '__call__')]

class SimpleXMLRPCDispatcher:
    """Mix-in class that dispatches XML-RPC requests.

    This class is used to register XML-RPC method handlers
    and then to dispatch them. There should never be any
    reason to instantiate this class directly.
    """

    def __init__(self, allow_none, encoding):
        self.funcs = {}
        self.instance = None
        self.allow_none = allow_none
        self.encoding = encoding

    def register_instance(self, instance, allow_dotted_names=False):
        """Registers an instance to respond to XML-RPC requests.

        Only one instance can be installed at a time.

        If the registered instance has a _dispatch method then that
        method will be called with the name of the XML-RPC method and
        its parameters as a tuple
        e.g. instance._dispatch('add',(2,3))

        If the registered instance does not have a _dispatch method
        then the instance will be searched to find a matching method
        and, if found, will be called. Methods beginning with an '_'
        are considered private and will not be called by
        SimpleXMLRPCServer.

        If a registered function matches a XML-RPC request, then it
        will be called instead of the registered instance.

        If the optional allow_dotted_names argument is true and the
        instance does not have a _dispatch method, method names
        containing dots are supported and resolved, as long as none of
        the name segments start with an '_'.

            *** SECURITY WARNING: ***

            Enabling the allow_dotted_names options 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.

        """

        self.instance = instance
        self.allow_dotted_names = allow_dotted_names

    def register_function(self, function, name = None):
        """Registers a function to respond to XML-RPC requests.

        The optional name argument can be used to set a Unicode name
        for the function.
        """

        if name is None:
            name = function.__name__
        self.funcs[name] = function

    def register_introspection_functions(self):
        """Registers the XML-RPC introspection methods in the system
        namespace.

        see http://xmlrpc.usefulinc.com/doc/reserved.html
        """

        self.funcs.update({'system.listMethods' : self.system_listMethods,
                      'system.methodSignature' : self.system_methodSignature,
                      'system.methodHelp' : self.system_methodHelp})

    def register_multicall_functions(self):
        """Registers the XML-RPC multicall method in the system
        namespace.

        see http://www.xmlrpc.com/discuss/msgReader$1208"""

        self.funcs.update({'system.multicall' : self.system_multicall})

    def _marshaled_dispatch(self, data, dispatch_method = None):
        """Dispatches an XML-RPC method from marshalled (XML) data.

        XML-RPC methods are dispatched from the marshalled (XML) data
        using the _dispatch method and the result is returned as
        marshalled data. For backwards compatibility, a dispatch
        function can be provided as an argument (see comment in
        SimpleXMLRPCRequestHandler.do_POST) but overriding the
        existing method through subclassing is the prefered means
        of changing method dispatch behavior.
        """

        try:
            params, method = loads(data)

            # generate response
            if dispatch_method is not None:
                response = dispatch_method(method, params)
            else:
                response = self._dispatch(method, params)
            # wrap response in a singleton tuple
            response = (response,)
            response = dumps(response, methodresponse=1,
                             allow_none=self.allow_none, encoding=self.encoding)
        except Fault as fault:
            response = dumps(fault, allow_none=self.allow_none,
                             encoding=self.encoding)
        except:
            # report exception back to server
            exc_type, exc_value, exc_tb = sys.exc_info()
            response = dumps(
                Fault(1, "%s:%s" % (exc_type, exc_value)),
                encoding=self.encoding, allow_none=self.allow_none,
                )

        return response

    def system_listMethods(self):
        """system.listMethods() => ['add', 'subtract', 'multiple']

        Returns a list of the methods supported by the server."""

        methods = set(self.funcs.keys())
        if self.instance is not None:
            # Instance can implement _listMethod to return a list of
            # methods
            if hasattr(self.instance, '_listMethods'):
                methods |= set(self.instance._listMethods())
            # if the instance has a _dispatch method then we
            # don't have enough information to provide a list
            # of methods
            elif not hasattr(self.instance, '_dispatch'):
                methods |= set(list_public_methods(self.instance))
        return sorted(methods)

    def system_methodSignature(self, method_name):
        """system.methodSignature('add') => [double, int, int]

        Returns a list describing the signature of the method. In the
        above example, the add method takes two integers as arguments
        and returns a double result.

        This server does NOT support system.methodSignature."""

        # See http://xmlrpc.usefulinc.com/doc/sysmethodsig.html

        return 'signatures not supported'

    def system_methodHelp(self, method_name):
        """system.methodHelp('add') => "Adds two integers together"

        Returns a string containing documentation for the specified method."""

        method = None
        if method_name in self.funcs:
            method = self.funcs[method_name]
        elif self.instance is not None:
            # Instance can implement _methodHelp to return help for a method
            if hasattr(self.instance, '_methodHelp'):
                return self.instance._methodHelp(method_name)
            # if the instance has a _dispatch method then we
            # don't have enough information to provide help
            elif not hasattr(self.instance, '_dispatch'):
                try:
                    method = resolve_dotted_attribute(
                                self.instance,
                                method_name,
                                self.allow_dotted_names
                                )
                except AttributeError:
                    pass

        # Note that we aren't checking that the method actually
        # be a callable object of some kind
        if method is None:
            return ""
        else:
            import pydoc
            return pydoc.getdoc(method)

    def system_multicall(self, call_list):
        """system.multicall([{'methodName': 'add', 'params': [2, 2]}, ...]) => \
[[4], ...]

        Allows the caller to package multiple XML-RPC calls into a single
        request.

        See http://www.xmlrpc.com/discuss/msgReader$1208
        """

        results = []
        for call in call_list:
            method_name = call['methodName']
            params = call['params']

            try:
                # XXX A marshalling error in any response will fail the entire
                # multicall. If someone cares they should fix this.
                results.append([self._dispatch(method_name, params)])
            except Fault as fault:
                results.append(
                    {'faultCode' : fault.faultCode,
                     'faultString' : fault.faultString}
                    )
            except:
                exc_type, exc_value, exc_tb = sys.exc_info()
                results.append(
                    {'faultCode' : 1,
                     'faultString' : "%s:%s" % (exc_type, exc_value)}
                    )
        return results

    def _dispatch(self, method, params):
        """Dispatches the XML-RPC method.

        XML-RPC calls are forwarded to a registered function that
        matches the called XML-RPC method name. If no such function
        exists then the call is forwarded to the registered instance,
        if available.

        If the registered instance has a _dispatch method then that
        method will be called with the name of the XML-RPC method and
        its parameters as a tuple
        e.g. instance._dispatch('add',(2,3))

        If the registered instance does not have a _dispatch method
        then the instance will be searched to find a matching method
        and, if found, will be called.

        Methods beginning with an '_' are considered private and will
        not be called.
        """

        func = None
        try:
            # check to see if a matching function has been registered
            func = self.funcs[method]
        except KeyError:
            if self.instance is not None:
                # check for a _dispatch method
                if hasattr(self.instance, '_dispatch'):
                    return self.instance._dispatch(method, params)
                else:
                    # call instance method directly
                    try:
                        func = resolve_dotted_attribute(
                            self.instance,
                            method,
                            self.allow_dotted_names
                            )
                    except AttributeError:
                        pass

        if func is not None:
            return func(*params)
        else:
            raise Exception('method "%s" is not supported' % method)

class SimpleXMLRPCRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    """Simple XML-RPC request handler class.

    Handles all HTTP POST requests and attempts to decode them as
    XML-RPC requests.
    """

    # Class attribute listing the accessible path components;
    # paths not on this list will result in a 404 error.
    rpc_paths = ('/', '/RPC2')

    def is_rpc_path_valid(self):
        if self.rpc_paths:
            return self.path in self.rpc_paths
        else:
            # If .rpc_paths is empty, just assume all paths are legal
            return True

    def do_POST(self):
        """Handles the HTTP POST request.

        Attempts to interpret all HTTP POST requests as XML-RPC calls,
        which are forwarded to the server's _dispatch method for handling.
        """

        # Check that the path is legal
        if not self.is_rpc_path_valid():
            self.report_404()
            return

        try:
            # Get arguments by reading body of request.
            # We read this in chunks to avoid straining
            # socket.read(); around the 10 or 15Mb mark, some platforms
            # begin to have problems (bug #792570).
            max_chunk_size = 10*1024*1024
            size_remaining = int(self.headers["content-length"])
            L = []
            while size_remaining:
                chunk_size = min(size_remaining, max_chunk_size)
                L.append(self.rfile.read(chunk_size))
                size_remaining -= len(L[-1])
            data = b''.join(L)

            # In previous versions of SimpleXMLRPCServer, _dispatch
            # could be overridden in this class, instead of in
            # SimpleXMLRPCDispatcher. To maintain backwards compatibility,
            # check to see if a subclass implements _dispatch and dispatch
            # using that method if present.
            response = self.server._marshaled_dispatch(
                    data, getattr(self, '_dispatch', None)
                )
        except Exception as e: # This should only happen if the module is buggy
            # internal error, report as HTTP server error
            self.send_response(500)

            # Send information about the exception if requested
            if hasattr(self.server, '_send_traceback_header') and \
                    self.server._send_traceback_header:
                self.send_header("X-exception", str(e))
                self.send_header("X-traceback", traceback.format_exc())

            self.end_headers()
        else:
            # Got a valid XML RPC response; convert to bytes first
            response = response.encode("utf-8")
            self.send_response(200)
            self.send_header("Content-type", "text/xml")
            self.send_header("Content-length", str(len(response)))
            self.end_headers()
            self.wfile.write(response)

            # shut down the connection
            self.wfile.flush()
            self.connection.shutdown(1)

    def report_404 (self):
            # Report a 404 error
        self.send_response(404)
        response = b'No such page'
        self.send_header("Content-type", "text/plain")
        self.send_header("Content-length", str(len(response)))
        self.end_headers()
        self.wfile.write(response)
        # shut down the connection
        self.wfile.flush()
        self.connection.shutdown(1)

    def log_request(self, code='-', size='-'):
        """Selectively log an accepted request."""

        if self.server.logRequests:
            BaseHTTPServer.BaseHTTPRequestHandler.log_request(self, code, size)

class SimpleXMLRPCServer(socketserver.TCPServer,
                         SimpleXMLRPCDispatcher):
    """Simple XML-RPC server.

    Simple XML-RPC server that allows functions and a single instance
    to be installed to handle requests. The default implementation
    attempts to dispatch XML-RPC calls to the functions or instance
    installed in the server. Override the _dispatch method inhereted
    from SimpleXMLRPCDispatcher to change this behavior.
    """

    allow_reuse_address = True

    # Warning: this is for debugging purposes only! Never set this to True in
    # production code, as will be sending out sensitive information (exception
    # and stack trace details) when exceptions are raised inside
    # SimpleXMLRPCRequestHandler.do_POST
    _send_traceback_header = False

    def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
                 logRequests=True, allow_none=False, encoding=None, bind_and_activate=True):
        self.logRequests = logRequests

        SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)
        socketserver.TCPServer.__init__(self, addr, requestHandler, bind_and_activate)

        # [Bug #1222790] If possible, set close-on-exec flag; if a
        # method spawns a subprocess, the subprocess shouldn't have
        # the listening socket open.
        if fcntl is not None and hasattr(fcntl, 'FD_CLOEXEC'):
            flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFD)
            flags |= fcntl.FD_CLOEXEC
            fcntl.fcntl(self.fileno(), fcntl.F_SETFD, flags)

class CGIXMLRPCRequestHandler(SimpleXMLRPCDispatcher):
    """Simple handler for XML-RPC data passed through CGI."""

    def __init__(self, allow_none=False, encoding=None):
        SimpleXMLRPCDispatcher.__init__(self, allow_none, encoding)

    def handle_xmlrpc(self, request_text):
        """Handle a single XML-RPC request"""

        response = self._marshaled_dispatch(request_text)

        print('Content-Type: text/xml')
        print('Content-Length: %d' % len(response))
        print()
        sys.stdout.write(response)

    def handle_get(self):
        """Handle a single HTTP GET request.

        Default implementation indicates an error because
        XML-RPC uses the POST method.
        """

        code = 400
        message, explain = \
                 BaseHTTPServer.BaseHTTPRequestHandler.responses[code]

        response = BaseHTTPServer.DEFAULT_ERROR_MESSAGE % \
            {
             'code' : code,
             'message' : message,
             'explain' : explain
            }
        print('Status: %d %s' % (code, message))
        print('Content-Type: text/html')
        print('Content-Length: %d' % len(response))
        print()
        sys.stdout.write(response)

    def handle_request(self, request_text = None):
        """Handle a single XML-RPC request passed through a CGI post method.

        If no XML data is given then it is read from stdin. The resulting
        XML-RPC response is printed to stdout along with the correct HTTP
        headers.
        """

        if request_text is None and \
            os.environ.get('REQUEST_METHOD', None) == 'GET':
            self.handle_get()
        else:
            # POST data is normally available through stdin
            if request_text is None:
                request_text = sys.stdin.read()

            self.handle_xmlrpc(request_text)


# -----------------------------------------------------------------------------
# Self documenting XML-RPC Server.

class ServerHTMLDoc(pydoc.HTMLDoc):
    """Class used to generate pydoc HTML document for a server"""

    def markup(self, text, escape=None, funcs={}, classes={}, methods={}):
        """Mark up some plain text, given a context of symbols to look for.
        Each context dictionary maps object names to anchor names."""
        escape = escape or self.escape
        results = []
        here = 0

        # XXX Note that this regular expression does not allow for the
        # hyperlinking of arbitrary strings being used as method
        # names. Only methods with names consisting of word characters
        # and '.'s are hyperlinked.
        pattern = re.compile(r'\b((http|ftp)://\S+[\w/]|'
                                r'RFC[- ]?(\d+)|'
                                r'PEP[- ]?(\d+)|'
                                r'(self\.)?((?:\w|\.)+))\b')
        while 1:
            match = pattern.search(text, here)
            if not match: break
            start, end = match.span()
            results.append(escape(text[here:start]))

            all, scheme, rfc, pep, selfdot, name = match.groups()
            if scheme:
                url = escape(all).replace('"', '"')
                results.append('<a href="%s">%s</a>' % (url, url))
            elif rfc:
                url = 'http://www.rfc-editor.org/rfc/rfc%d.txt' % int(rfc)
                results.append('<a href="%s">%s</a>' % (url, escape(all)))
            elif pep:
                url = 'http://www.python.org/dev/peps/pep-%04d/' % int(pep)
                results.append('<a href="%s">%s</a>' % (url, escape(all)))
            elif text[end:end+1] == '(':
                results.append(self.namelink(name, methods, funcs, classes))
            elif selfdot:
                results.append('self.<strong>%s</strong>' % name)
            else:
                results.append(self.namelink(name, classes))
            here = end
        results.append(escape(text[here:]))
        return ''.join(results)

    def docroutine(self, object, name, mod=None,
                   funcs={}, classes={}, methods={}, cl=None):
        """Produce HTML documentation for a function or method object."""

        anchor = (cl and cl.__name__ or '') + '-' + name
        note = ''

        title = '<a name="%s"><strong>%s</strong></a>' % (
            self.escape(anchor), self.escape(name))

        if inspect.ismethod(object):
            args, varargs, varkw, defaults = inspect.getargspec(object)
            # exclude the argument bound to the instance, it will be
            # confusing to the non-Python user
            argspec = inspect.formatargspec (
                    args[1:],
                    varargs,
                    varkw,
                    defaults,
                    formatvalue=self.formatvalue
                )
        elif inspect.isfunction(object):
            args, varargs, varkw, defaults = inspect.getargspec(object)
            argspec = inspect.formatargspec(
                args, varargs, varkw, defaults, formatvalue=self.formatvalue)
        else:
            argspec = '(...)'

        if isinstance(object, tuple):
            argspec = object[0] or argspec
            docstring = object[1] or ""
        else:
            docstring = pydoc.getdoc(object)

        decl = title + argspec + (note and self.grey(
               '<font face="helvetica, arial">%s</font>' % note))

        doc = self.markup(
            docstring, self.preformat, funcs, classes, methods)
        doc = doc and '<dd><tt>%s</tt></dd>' % doc
        return '<dl><dt>%s</dt>%s</dl>\n' % (decl, doc)

    def docserver(self, server_name, package_documentation, methods):
        """Produce HTML documentation for an XML-RPC server."""

        fdict = {}
        for key, value in methods.items():
            fdict[key] = '#-' + key
            fdict[value] = fdict[key]

        server_name = self.escape(server_name)
        head = '<big><big><strong>%s</strong></big></big>' % server_name
        result = self.heading(head, '#ffffff', '#7799ee')

        doc = self.markup(package_documentation, self.preformat, fdict)
        doc = doc and '<tt>%s</tt>' % doc
        result = result + '<p>%s</p>\n' % doc

        contents = []
        method_items = sorted(methods.items())
        for key, value in method_items:
            contents.append(self.docroutine(value, key, funcs=fdict))
        result = result + self.bigsection(
            'Methods', '#ffffff', '#eeaa77', ''.join(contents))

        return result

class XMLRPCDocGenerator:
    """Generates documentation for an XML-RPC server.

    This class is designed as mix-in and should not
    be constructed directly.
    """

    def __init__(self):
        # setup variables used for HTML documentation
        self.server_name = 'XML-RPC Server Documentation'
        self.server_documentation = \
            "This server exports the following methods through the XML-RPC "\
            "protocol."
        self.server_title = 'XML-RPC Server Documentation'

    def set_server_title(self, server_title):
        """Set the HTML title of the generated server documentation"""

        self.server_title = server_title

    def set_server_name(self, server_name):
        """Set the name of the generated HTML server documentation"""

        self.server_name = server_name

    def set_server_documentation(self, server_documentation):
        """Set the documentation string for the entire server."""

        self.server_documentation = server_documentation

    def generate_html_documentation(self):
        """generate_html_documentation() => html documentation for the server

        Generates HTML documentation for the server using introspection for
        installed functions and instances that do not implement the
        _dispatch method. Alternatively, instances can choose to implement
        the _get_method_argstring(method_name) method to provide the
        argument string used in the documentation and the
        _methodHelp(method_name) method to provide the help text used
        in the documentation."""

        methods = {}

        for method_name in self.system_listMethods():
            if method_name in self.funcs:
                method = self.funcs[method_name]
            elif self.instance is not None:
                method_info = [None, None] # argspec, documentation
                if hasattr(self.instance, '_get_method_argstring'):
                    method_info[0] = self.instance._get_method_argstring(method_name)
                if hasattr(self.instance, '_methodHelp'):
                    method_info[1] = self.instance._methodHelp(method_name)

                method_info = tuple(method_info)
                if method_info != (None, None):
                    method = method_info
                elif not hasattr(self.instance, '_dispatch'):
                    try:
                        method = resolve_dotted_attribute(
                                    self.instance,
                                    method_name
                                    )
                    except AttributeError:
                        method = method_info
                else:
                    method = method_info
            else:
                assert 0, "Could not find method in self.functions and no "\
                          "instance installed"

            methods[method_name] = method

        documenter = ServerHTMLDoc()
        documentation = documenter.docserver(
                                self.server_name,
                                self.server_documentation,
                                methods
                            )

        return documenter.page(self.server_title, documentation)

class DocXMLRPCRequestHandler(SimpleXMLRPCRequestHandler):
    """XML-RPC and documentation request handler class.

    Handles all HTTP POST requests and attempts to decode them as
    XML-RPC requests.

    Handles all HTTP GET requests and interprets them as requests
    for documentation.
    """

    def do_GET(self):
        """Handles the HTTP GET request.

        Interpret all HTTP GET requests as requests for server
        documentation.
        """
        # Check that the path is legal
        if not self.is_rpc_path_valid():
            self.report_404()
            return

        response = self.server.generate_html_documentation()
        self.send_response(200)
        self.send_header("Content-type", "text/html")
        self.send_header("Content-length", str(len(response)))
        self.end_headers()
        self.wfile.write(response.encode())

        # shut down the connection
        self.wfile.flush()
        self.connection.shutdown(1)

class DocXMLRPCServer(  SimpleXMLRPCServer,
                        XMLRPCDocGenerator):
    """XML-RPC and HTML documentation server.

    Adds the ability to serve server documentation to the capabilities
    of SimpleXMLRPCServer.
    """

    def __init__(self, addr, requestHandler=DocXMLRPCRequestHandler,
                 logRequests=1, allow_none=False, encoding=None,
                 bind_and_activate=True):
        SimpleXMLRPCServer.__init__(self, addr, requestHandler, logRequests,
                                    allow_none, encoding, bind_and_activate)
        XMLRPCDocGenerator.__init__(self)

class DocCGIXMLRPCRequestHandler(   CGIXMLRPCRequestHandler,
                                    XMLRPCDocGenerator):
    """Handler for XML-RPC data and documentation requests passed through
    CGI"""

    def handle_get(self):
        """Handles the HTTP GET request.

        Interpret all HTTP GET requests as requests for server
        documentation.
        """

        response = self.generate_html_documentation()

        print('Content-Type: text/html')
        print('Content-Length: %d' % len(response))
        print()
        sys.stdout.write(response)

    def __init__(self):
        CGIXMLRPCRequestHandler.__init__(self)
        XMLRPCDocGenerator.__init__(self)


if __name__ == '__main__':
    print('Running XML-RPC server on port 8000')
    server = SimpleXMLRPCServer(("localhost", 8000))
    server.register_function(pow)
    server.register_function(lambda x,y: x+y, 'add')
    server.serve_forever()