Doc/library/xmlrpclib.rst - platform/external/python/cpython2 - Gitiles

 :mod:`xmlrpclib` --- XML-RPC client access
 ==========================================

 .. module:: xmlrpclib
    :synopsis: XML-RPC client access.
 .. moduleauthor:: Fredrik Lundh <fredrik@pythonware.com>
 .. sectionauthor:: Eric S. Raymond <esr@snark.thyrsus.com>


 .. XXX Not everything is documented yet.  It might be good to describe
    Marshaller, Unmarshaller, getparser, dumps, loads, and Transport.

 XML-RPC is a Remote Procedure Call method that uses XML passed via HTTP as a
 transport.  With it, a client can call methods with parameters on a remote
 server (the server is named by a URI) and get back structured data.  This module
 supports writing XML-RPC client code; it handles all the details of translating
 between conformable Python objects and XML on the wire.


 .. class:: ServerProxy(uri[, transport[, encoding[, verbose[,  allow_none[, use_datetime]]]]])

    A :class:`ServerProxy` instance is an object that manages communication with a
    remote XML-RPC server.  The required first argument is a URI (Uniform Resource
    Indicator), and will normally be the URL of the server.  The optional second
    argument is a transport factory instance; by default it is an internal
    :class:`SafeTransport` instance for https: URLs and an internal HTTP
    :class:`Transport` instance otherwise.  The optional third argument is an
    encoding, by default UTF-8. The optional fourth argument is a debugging flag.
    If *allow_none* is true,  the Python constant ``None`` will be translated into
    XML; the default behaviour is for ``None`` to raise a :exc:`TypeError`. This is
    a commonly-used extension to the XML-RPC specification, but isn't supported by
    all clients and servers; see http://ontosys.com/xml-rpc/extensions.php for a
    description.  The *use_datetime* flag can be used to cause date/time values to
    be presented as :class:`datetime.datetime` objects; this is false by default.
    :class:`datetime.datetime`, :class:`datetime.date` and :class:`datetime.time`
    objects may be passed to calls.  :class:`datetime.date` objects are converted
    with a time of "00:00:00". :class:`datetime.time` objects are converted using
    today's date.

    Both the HTTP and HTTPS transports support the URL syntax extension for HTTP
    Basic Authentication: ``http://user:pass@host:port/path``.  The  ``user:pass``
    portion will be base64-encoded as an HTTP 'Authorization' header, and sent to
    the remote server as part of the connection process when invoking an XML-RPC
    method.  You only need to use this if the remote server requires a Basic
    Authentication user and password.

    The returned instance is a proxy object with methods that can be used to invoke
    corresponding RPC calls on the remote server.  If the remote server supports the
    introspection API, the proxy can also be used to query the remote server for the
    methods it supports (service discovery) and fetch other server-associated
    metadata.

    :class:`ServerProxy` instance methods take Python basic types and objects as
    arguments and return Python basic types and classes.  Types that are conformable
    (e.g. that can be marshalled through XML), include the following (and except
    where noted, they are unmarshalled as the same Python type):

    +---------------------------------+---------------------------------------------+
    | Name                            | Meaning                                     |
    +=================================+=============================================+
    | :const:`boolean`                | The :const:`True` and :const:`False`        |
    |                                 | constants                                   |
    +---------------------------------+---------------------------------------------+
    | :const:`integers`               | Pass in directly                            |
    +---------------------------------+---------------------------------------------+
    | :const:`floating-point numbers` | Pass in directly                            |
    +---------------------------------+---------------------------------------------+
    | :const:`strings`                | Pass in directly                            |
    +---------------------------------+---------------------------------------------+
    | :const:`arrays`                 | Any Python sequence type containing         |
    |                                 | conformable elements. Arrays are returned   |
    |                                 | as lists                                    |
    +---------------------------------+---------------------------------------------+
    | :const:`structures`             | A Python dictionary. Keys must be strings,  |
    |                                 | values may be any conformable type. Objects |
    |                                 | of user-defined classes can be passed in;   |
    |                                 | only their *__dict__* attribute is          |
    |                                 | transmitted.                                |
    +---------------------------------+---------------------------------------------+
    | :const:`dates`                  | in seconds since the epoch (pass in an      |
    |                                 | instance of the :class:`DateTime` class) or |
    |                                 | a :class:`datetime.datetime`,               |
    |                                 | :class:`datetime.date` or                   |
    |                                 | :class:`datetime.time` instance             |
    +---------------------------------+---------------------------------------------+
    | :const:`binary data`            | pass in an instance of the :class:`Binary`  |
    |                                 | wrapper class                               |
    +---------------------------------+---------------------------------------------+

    This is the full set of data types supported by XML-RPC.  Method calls may also
    raise a special :exc:`Fault` instance, used to signal XML-RPC server errors, or
    :exc:`ProtocolError` used to signal an error in the HTTP/HTTPS transport layer.
    Both :exc:`Fault` and :exc:`ProtocolError` derive from a base class called
    :exc:`Error`.  Note that even though starting with Python 2.2 you can subclass
    builtin types, the xmlrpclib module currently does not marshal instances of such
    subclasses.

    When passing strings, characters special to XML such as ``<``, ``>``, and ``&``
    will be automatically escaped.  However, it's the caller's responsibility to
    ensure that the string is free of characters that aren't allowed in XML, such as
    the control characters with ASCII values between 0 and 31 (except, of course,
    tab, newline and carriage return); failing to do this will result in an XML-RPC
    request that isn't well-formed XML.  If you have to pass arbitrary strings via
    XML-RPC, use the :class:`Binary` wrapper class described below.

    :class:`Server` is retained as an alias for :class:`ServerProxy` for backwards
    compatibility.  New code should use :class:`ServerProxy`.


 .. seealso::

    `XML-RPC HOWTO <http://www.tldp.org/HOWTO/XML-RPC-HOWTO/index.html>`_
       A good description of XML-RPC operation and client software in several languages.
       Contains pretty much everything an XML-RPC client developer needs to know.

    `XML-RPC Introspection <http://xmlrpc-c.sourceforge.net/introspection.html>`_
       Describes the XML-RPC protocol extension for introspection.


 .. _serverproxy-objects:

 ServerProxy Objects
 -------------------

 A :class:`ServerProxy` instance has a method corresponding to each remote
 procedure call accepted by the XML-RPC server.  Calling the method performs an
 RPC, dispatched by both name and argument signature (e.g. the same method name
 can be overloaded with multiple argument signatures).  The RPC finishes by
 returning a value, which may be either returned data in a conformant type or a
 :class:`Fault` or :class:`ProtocolError` object indicating an error.

 Servers that support the XML introspection API support some common methods
 grouped under the reserved :attr:`system` member:


 .. method:: ServerProxy.system.listMethods()

    This method returns a list of strings, one for each (non-system) method
    supported by the XML-RPC server.


 .. method:: ServerProxy.system.methodSignature(name)

    This method takes one parameter, the name of a method implemented by the XML-RPC
    server.It returns an array of possible signatures for this method. A signature
    is an array of types. The first of these types is the return type of the method,
    the rest are parameters.

    Because multiple signatures (ie. overloading) is permitted, this method returns
    a list of signatures rather than a singleton.

    Signatures themselves are restricted to the top level parameters expected by a
    method. For instance if a method expects one array of structs as a parameter,
    and it returns a string, its signature is simply "string, array". If it expects
    three integers and returns a string, its signature is "string, int, int, int".

    If no signature is defined for the method, a non-array value is returned. In
    Python this means that the type of the returned  value will be something other
    that list.


 .. method:: ServerProxy.system.methodHelp(name)

    This method takes one parameter, the name of a method implemented by the XML-RPC
    server.  It returns a documentation string describing the use of that method. If
    no such string is available, an empty string is returned. The documentation
    string may contain HTML markup.


 .. _boolean-objects:

 Boolean Objects
 ---------------

 This class may be initialized from any Python value; the instance returned
 depends only on its truth value.  It supports various Python operators through
 :meth:`__cmp__`, :meth:`__repr__`, :meth:`__int__`, and :meth:`__bool__`
 methods, all implemented in the obvious ways.

 It also has the following method, supported mainly for internal use by the
 unmarshalling code:


 .. method:: Boolean.encode(out)

    Write the XML-RPC encoding of this Boolean item to the out stream object.

 A working example follows. The server code::

    import xmlrpclib
    from SimpleXMLRPCServer import SimpleXMLRPCServer

    def is_even(n):
        return n%2 == 0

    server = SimpleXMLRPCServer(("localhost", 8000))
    print("Listening on port 8000...")
    server.register_function(is_even, "is_even")
    server.serve_forever()

 The client code for the preceding server::

    import xmlrpclib

    proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
    print("3 is even: %s" % str(proxy.is_even(3)))
    print("100 is even: %s" % str(proxy.is_even(100)))

 .. _datetime-objects:

 DateTime Objects
 ----------------

 This class may be initialized with seconds since the epoch, a time tuple, an ISO
 8601 time/date string, or a :class:`datetime.datetime`, :class:`datetime.date`
 or :class:`datetime.time` instance.  It has the following methods, supported
 mainly for internal use by the marshalling/unmarshalling code:


 .. method:: DateTime.decode(string)

    Accept a string as the instance's new time value.


 .. method:: DateTime.encode(out)

    Write the XML-RPC encoding of this :class:`DateTime` item to the *out* stream
    object.

 It also supports certain of Python's built-in operators through  :meth:`__cmp__`
 and :meth:`__repr__` methods.

 A working example follows. The server code::

    import datetime
    from SimpleXMLRPCServer import SimpleXMLRPCServer
    import xmlrpclib

    def today():
        today = datetime.datetime.today()
        return xmlrpclib.DateTime(today)

    server = SimpleXMLRPCServer(("localhost", 8000))
    print("Listening on port 8000...")
    server.register_function(today, "today")
    server.serve_forever()

 The client code for the preceding server::

    import xmlrpclib
    import datetime

    proxy = xmlrpclib.ServerProxy("http://localhost:8000/")

    today = proxy.today()
    # convert the ISO8601 string to a datetime object
    converted = datetime.datetime.strptime(today.value, "%Y%m%dT%H:%M:%S")
    print("Today: %s" % converted.strftime("%d.%m.%Y, %H:%M"))

 .. _binary-objects:

 Binary Objects
 --------------

 This class may be initialized from string data (which may include NULs). The
 primary access to the content of a :class:`Binary` object is provided by an
 attribute:


 .. attribute:: Binary.data

    The binary data encapsulated by the :class:`Binary` instance.  The data is
    provided as an 8-bit string.

 :class:`Binary` objects have the following methods, supported mainly for
 internal use by the marshalling/unmarshalling code:


 .. method:: Binary.decode(string)

    Accept a base64 string and decode it as the instance's new data.


 .. method:: Binary.encode(out)

    Write the XML-RPC base 64 encoding of this binary item to the out stream object.

 It also supports certain of Python's built-in operators through a
 :meth:`__cmp__` method.

 Example usage of the binary objects.  We're going to transfer an image over
 XMLRPC::

    from SimpleXMLRPCServer import SimpleXMLRPCServer
    import xmlrpclib

    def python_logo():
         handle = open("python_logo.jpg")
         return xmlrpclib.Binary(handle.read())
         handle.close()

    server = SimpleXMLRPCServer(("localhost", 8000))
    print("Listening on port 8000...")
    server.register_function(python_logo, 'python_logo')

    server.serve_forever()

 The client gets the image and saves it to a file::

    import xmlrpclib

    proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
    handle = open("fetched_python_logo.jpg", "w")
    handle.write(proxy.python_logo().data)
    handle.close()

 .. _fault-objects:

 Fault Objects
 -------------

 A :class:`Fault` object encapsulates the content of an XML-RPC fault tag. Fault
 objects have the following members:


 .. attribute:: Fault.faultCode

    A string indicating the fault type.


 .. attribute:: Fault.faultString

    A string containing a diagnostic message associated with the fault.

 In the following example we're going to intentionally cause a :exc:`Fault` by
 returning a complex type object.  The server code::

    from SimpleXMLRPCServer import SimpleXMLRPCServer

    # A marshalling error is going to occur because we're returning a
    # complex number
    def add(x,y):
        return x+y+0j

    server = SimpleXMLRPCServer(("localhost", 8000))
    print("Listening on port 8000...")
    server.register_function(add, 'add')

    server.serve_forever()

 The client code for the preceding server::

    import xmlrpclib

    proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
    try:
        proxy.add(2, 5)
    except xmlrpclib.Fault, err:
        print("A fault occured")
        print("Fault code: %d" % err.faultCode)
        print("Fault string: %s" % err.faultString)


 .. _protocol-error-objects:

 ProtocolError Objects
 ---------------------

 A :class:`ProtocolError` object describes a protocol error in the underlying
 transport layer (such as a 404 'not found' error if the server named by the URI
 does not exist).  It has the following members:


 .. attribute:: ProtocolError.url

    The URI or URL that triggered the error.


 .. attribute:: ProtocolError.errcode

    The error code.


 .. attribute:: ProtocolError.errmsg

    The error message or diagnostic string.


 .. attribute:: ProtocolError.headers

    A dict containing the headers of the HTTP/HTTPS request that triggered the
    error.

 In the following example we're going to intentionally cause a :exc:`ProtocolError`
 by providing an invalid URI::

    import xmlrpclib

    # create a ServerProxy with an invalid URI
    proxy = xmlrpclib.ServerProxy("http://invalidaddress/")

    try:
        proxy.some_method()
    except xmlrpclib.ProtocolError, err:
        print("A protocol error occured")
        print("URL: %s" % err.url)
        print("HTTP/HTTPS headers: %s" % err.headers)
        print("Error code: %d" % err.errcode)
        print("Error message: %s" % err.errmsg)

 MultiCall Objects
 -----------------

 In http://www.xmlrpc.com/discuss/msgReader%241208, an approach is presented to
 encapsulate multiple calls to a remote server into a single request.


 .. class:: MultiCall(server)

    Create an object used to boxcar method calls. *server* is the eventual target of
    the call. Calls can be made to the result object, but they will immediately
    return ``None``, and only store the call name and parameters in the
    :class:`MultiCall` object. Calling the object itself causes all stored calls to
    be transmitted as a single ``system.multicall`` request. The result of this call
    is a :term:`generator`; iterating over this generator yields the individual
    results.

 A usage example of this class follows.  The server code ::

    from SimpleXMLRPCServer import SimpleXMLRPCServer

    def add(x,y):
        return x+y

    def subtract(x, y):
        return x-y

    def multiply(x, y):
        return x*y

    def divide(x, y):
        return x/y

    # A simple server with simple arithmetic functions
    server = SimpleXMLRPCServer(("localhost", 8000))
    print("Listening on port 8000...")
    server.register_multicall_functions()
    server.register_function(add, 'add')
    server.register_function(subtract, 'subtract')
    server.register_function(multiply, 'multiply')
    server.register_function(divide, 'divide')
    server.serve_forever()

 The client code for the preceding server::

    import xmlrpclib

    proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
    multicall = xmlrpclib.MultiCall(proxy)
    multicall.add(7,3)
    multicall.subtract(7,3)
    multicall.multiply(7,3)
    multicall.divide(7,3)
    result = multicall()

    print("7+3=%d, 7-3=%d, 7*3=%d, 7/3=%d" % tuple(result))


 Convenience Functions
 ---------------------


 .. function:: boolean(value)

    Convert any Python value to one of the XML-RPC Boolean constants, ``True`` or
    ``False``.


 .. function:: dumps(params[, methodname[,  methodresponse[, encoding[, allow_none]]]])

    Convert *params* into an XML-RPC request. or into a response if *methodresponse*
    is true. *params* can be either a tuple of arguments or an instance of the
    :exc:`Fault` exception class.  If *methodresponse* is true, only a single value
    can be returned, meaning that *params* must be of length 1. *encoding*, if
    supplied, is the encoding to use in the generated XML; the default is UTF-8.
    Python's :const:`None` value cannot be used in standard XML-RPC; to allow using
    it via an extension,  provide a true value for *allow_none*.


 .. function:: loads(data[, use_datetime])

    Convert an XML-RPC request or response into Python objects, a ``(params,
    methodname)``.  *params* is a tuple of argument; *methodname* is a string, or
    ``None`` if no method name is present in the packet. If the XML-RPC packet
    represents a fault condition, this function will raise a :exc:`Fault` exception.
    The *use_datetime* flag can be used to cause date/time values to be presented as
    :class:`datetime.datetime` objects; this is false by default. Note that even if
    you call an XML-RPC method with :class:`datetime.date` or :class:`datetime.time`
    objects, they are converted to :class:`DateTime` objects internally, so only
    :class:`datetime.datetime` objects will be returned.


 .. _xmlrpc-client-example:

 Example of Client Usage
 -----------------------

 ::

    # simple test program (from the XML-RPC specification)
    from xmlrpclib import ServerProxy, Error

    # server = ServerProxy("http://localhost:8000") # local server
    server = ServerProxy("http://betty.userland.com")

    print(server)

    try:
        print(server.examples.getStateName(41))
    except Error as v:
        print("ERROR", v)

 To access an XML-RPC server through a proxy, you need to define  a custom
 transport.  The following example shows how:

 .. Example taken from http://lowlife.jp/nobonobo/wiki/xmlrpcwithproxy.html

 ::

    import xmlrpclib, httplib

    class ProxiedTransport(xmlrpclib.Transport):
        def set_proxy(self, proxy):
            self.proxy = proxy
        def make_connection(self, host):
            self.realhost = host
    	h = httplib.HTTP(self.proxy)
    	return h
        def send_request(self, connection, handler, request_body):
            connection.putrequest("POST", 'http://%s%s' % (self.realhost, handler))
        def send_host(self, connection, host):
            connection.putheader('Host', self.realhost)

    p = ProxiedTransport()
    p.set_proxy('proxy-server:8080')
    server = xmlrpclib.Server('http://time.xmlrpc.com/RPC2', transport=p)
    print(server.currentTime.getCurrentTime())


 Example of Client and Server Usage
 ----------------------------------

 See :ref:`simplexmlrpcserver-example`.
	:mod:`xmlrpclib` --- XML-RPC client access
	==========================================

	.. module:: xmlrpclib
	:synopsis: XML-RPC client access.
	.. moduleauthor:: Fredrik Lundh <fredrik@pythonware.com>
	.. sectionauthor:: Eric S. Raymond <esr@snark.thyrsus.com>


	.. XXX Not everything is documented yet. It might be good to describe
	Marshaller, Unmarshaller, getparser, dumps, loads, and Transport.

	XML-RPC is a Remote Procedure Call method that uses XML passed via HTTP as a
	transport. With it, a client can call methods with parameters on a remote
	server (the server is named by a URI) and get back structured data. This module
	supports writing XML-RPC client code; it handles all the details of translating
	between conformable Python objects and XML on the wire.


	.. class:: ServerProxy(uri[, transport[, encoding[, verbose[, allow_none[, use_datetime]]]]])

	A :class:`ServerProxy` instance is an object that manages communication with a
	remote XML-RPC server. The required first argument is a URI (Uniform Resource
	Indicator), and will normally be the URL of the server. The optional second
	argument is a transport factory instance; by default it is an internal
	:class:`SafeTransport` instance for https: URLs and an internal HTTP
	:class:`Transport` instance otherwise. The optional third argument is an
	encoding, by default UTF-8. The optional fourth argument is a debugging flag.
	If allow_none is true, the Python constant ``None`` will be translated into
	XML; the default behaviour is for ``None`` to raise a :exc:`TypeError`. This is
	a commonly-used extension to the XML-RPC specification, but isn't supported by
	all clients and servers; see http://ontosys.com/xml-rpc/extensions.php for a
	description. The use_datetime flag can be used to cause date/time values to
	be presented as :class:`datetime.datetime` objects; this is false by default.
	:class:`datetime.datetime`, :class:`datetime.date` and :class:`datetime.time`
	objects may be passed to calls. :class:`datetime.date` objects are converted
	with a time of "00:00:00". :class:`datetime.time` objects are converted using
	today's date.

	Both the HTTP and HTTPS transports support the URL syntax extension for HTTP
	Basic Authentication: ``http://user:pass@host:port/path``. The ``user:pass``
	portion will be base64-encoded as an HTTP 'Authorization' header, and sent to
	the remote server as part of the connection process when invoking an XML-RPC
	method. You only need to use this if the remote server requires a Basic
	Authentication user and password.

	The returned instance is a proxy object with methods that can be used to invoke
	corresponding RPC calls on the remote server. If the remote server supports the
	introspection API, the proxy can also be used to query the remote server for the
	methods it supports (service discovery) and fetch other server-associated
	metadata.

	:class:`ServerProxy` instance methods take Python basic types and objects as
	arguments and return Python basic types and classes. Types that are conformable
	(e.g. that can be marshalled through XML), include the following (and except
	where noted, they are unmarshalled as the same Python type):

	+---------------------------------+---------------------------------------------+
	\| Name \| Meaning \|
	+=================================+=============================================+
	\| :const:`boolean` \| The :const:`True` and :const:`False` \|
	\| \| constants \|
	+---------------------------------+---------------------------------------------+
	\| :const:`integers` \| Pass in directly \|
	+---------------------------------+---------------------------------------------+
	\| :const:`floating-point numbers` \| Pass in directly \|
	+---------------------------------+---------------------------------------------+
	\| :const:`strings` \| Pass in directly \|
	+---------------------------------+---------------------------------------------+
	\| :const:`arrays` \| Any Python sequence type containing \|
	\| \| conformable elements. Arrays are returned \|
	\| \| as lists \|
	+---------------------------------+---------------------------------------------+
	\| :const:`structures` \| A Python dictionary. Keys must be strings, \|
	\| \| values may be any conformable type. Objects \|
	\| \| of user-defined classes can be passed in; \|
	\| \| only their __dict__ attribute is \|
	\| \| transmitted. \|
	+---------------------------------+---------------------------------------------+
	\| :const:`dates` \| in seconds since the epoch (pass in an \|
	\| \| instance of the :class:`DateTime` class) or \|
	\| \| a :class:`datetime.datetime`, \|
	\| \| :class:`datetime.date` or \|
	\| \| :class:`datetime.time` instance \|
	+---------------------------------+---------------------------------------------+
	\| :const:`binary data` \| pass in an instance of the :class:`Binary` \|
	\| \| wrapper class \|
	+---------------------------------+---------------------------------------------+

	This is the full set of data types supported by XML-RPC. Method calls may also
	raise a special :exc:`Fault` instance, used to signal XML-RPC server errors, or
	:exc:`ProtocolError` used to signal an error in the HTTP/HTTPS transport layer.
	Both :exc:`Fault` and :exc:`ProtocolError` derive from a base class called
	:exc:`Error`. Note that even though starting with Python 2.2 you can subclass
	builtin types, the xmlrpclib module currently does not marshal instances of such
	subclasses.

	When passing strings, characters special to XML such as ``<``, ``>``, and ``&``
	will be automatically escaped. However, it's the caller's responsibility to
	ensure that the string is free of characters that aren't allowed in XML, such as
	the control characters with ASCII values between 0 and 31 (except, of course,
	tab, newline and carriage return); failing to do this will result in an XML-RPC
	request that isn't well-formed XML. If you have to pass arbitrary strings via
	XML-RPC, use the :class:`Binary` wrapper class described below.

	:class:`Server` is retained as an alias for :class:`ServerProxy` for backwards
	compatibility. New code should use :class:`ServerProxy`.


	.. seealso::

	`XML-RPC HOWTO <http://www.tldp.org/HOWTO/XML-RPC-HOWTO/index.html>`_
	A good description of XML-RPC operation and client software in several languages.
	Contains pretty much everything an XML-RPC client developer needs to know.

	`XML-RPC Introspection <http://xmlrpc-c.sourceforge.net/introspection.html>`_
	Describes the XML-RPC protocol extension for introspection.


	.. _serverproxy-objects:

	ServerProxy Objects
	-------------------

	A :class:`ServerProxy` instance has a method corresponding to each remote
	procedure call accepted by the XML-RPC server. Calling the method performs an
	RPC, dispatched by both name and argument signature (e.g. the same method name
	can be overloaded with multiple argument signatures). The RPC finishes by
	returning a value, which may be either returned data in a conformant type or a
	:class:`Fault` or :class:`ProtocolError` object indicating an error.

	Servers that support the XML introspection API support some common methods
	grouped under the reserved :attr:`system` member:


	.. method:: ServerProxy.system.listMethods()

	This method returns a list of strings, one for each (non-system) method
	supported by the XML-RPC server.


	.. method:: ServerProxy.system.methodSignature(name)

	This method takes one parameter, the name of a method implemented by the XML-RPC
	server.It returns an array of possible signatures for this method. A signature
	is an array of types. The first of these types is the return type of the method,
	the rest are parameters.

	Because multiple signatures (ie. overloading) is permitted, this method returns
	a list of signatures rather than a singleton.

	Signatures themselves are restricted to the top level parameters expected by a
	method. For instance if a method expects one array of structs as a parameter,
	and it returns a string, its signature is simply "string, array". If it expects
	three integers and returns a string, its signature is "string, int, int, int".

	If no signature is defined for the method, a non-array value is returned. In
	Python this means that the type of the returned value will be something other
	that list.


	.. method:: ServerProxy.system.methodHelp(name)

	This method takes one parameter, the name of a method implemented by the XML-RPC
	server. It returns a documentation string describing the use of that method. If
	no such string is available, an empty string is returned. The documentation
	string may contain HTML markup.


	.. _boolean-objects:

	Boolean Objects
	---------------

	This class may be initialized from any Python value; the instance returned
	depends only on its truth value. It supports various Python operators through
	:meth:`__cmp__`, :meth:`__repr__`, :meth:`__int__`, and :meth:`__bool__`
	methods, all implemented in the obvious ways.

	It also has the following method, supported mainly for internal use by the
	unmarshalling code:


	.. method:: Boolean.encode(out)

	Write the XML-RPC encoding of this Boolean item to the out stream object.

	A working example follows. The server code::

	import xmlrpclib
	from SimpleXMLRPCServer import SimpleXMLRPCServer

	def is_even(n):
	return n%2 == 0

	server = SimpleXMLRPCServer(("localhost", 8000))
	print("Listening on port 8000...")
	server.register_function(is_even, "is_even")
	server.serve_forever()

	The client code for the preceding server::

	import xmlrpclib

	proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
	print("3 is even: %s" % str(proxy.is_even(3)))
	print("100 is even: %s" % str(proxy.is_even(100)))

	.. _datetime-objects:

	DateTime Objects
	----------------

	This class may be initialized with seconds since the epoch, a time tuple, an ISO
	8601 time/date string, or a :class:`datetime.datetime`, :class:`datetime.date`
	or :class:`datetime.time` instance. It has the following methods, supported
	mainly for internal use by the marshalling/unmarshalling code:


	.. method:: DateTime.decode(string)

	Accept a string as the instance's new time value.


	.. method:: DateTime.encode(out)

	Write the XML-RPC encoding of this :class:`DateTime` item to the out stream
	object.

	It also supports certain of Python's built-in operators through :meth:`__cmp__`
	and :meth:`__repr__` methods.

	A working example follows. The server code::

	import datetime
	from SimpleXMLRPCServer import SimpleXMLRPCServer
	import xmlrpclib

	def today():
	today = datetime.datetime.today()
	return xmlrpclib.DateTime(today)

	server = SimpleXMLRPCServer(("localhost", 8000))
	print("Listening on port 8000...")
	server.register_function(today, "today")
	server.serve_forever()

	The client code for the preceding server::

	import xmlrpclib
	import datetime

	proxy = xmlrpclib.ServerProxy("http://localhost:8000/")

	today = proxy.today()
	# convert the ISO8601 string to a datetime object
	converted = datetime.datetime.strptime(today.value, "%Y%m%dT%H:%M:%S")
	print("Today: %s" % converted.strftime("%d.%m.%Y, %H:%M"))

	.. _binary-objects:

	Binary Objects
	--------------

	This class may be initialized from string data (which may include NULs). The
	primary access to the content of a :class:`Binary` object is provided by an
	attribute:


	.. attribute:: Binary.data

	The binary data encapsulated by the :class:`Binary` instance. The data is
	provided as an 8-bit string.

	:class:`Binary` objects have the following methods, supported mainly for
	internal use by the marshalling/unmarshalling code:


	.. method:: Binary.decode(string)

	Accept a base64 string and decode it as the instance's new data.


	.. method:: Binary.encode(out)

	Write the XML-RPC base 64 encoding of this binary item to the out stream object.

	It also supports certain of Python's built-in operators through a
	:meth:`__cmp__` method.

	Example usage of the binary objects. We're going to transfer an image over
	XMLRPC::

	from SimpleXMLRPCServer import SimpleXMLRPCServer
	import xmlrpclib

	def python_logo():
	handle = open("python_logo.jpg")
	return xmlrpclib.Binary(handle.read())
	handle.close()

	server = SimpleXMLRPCServer(("localhost", 8000))
	print("Listening on port 8000...")
	server.register_function(python_logo, 'python_logo')

	server.serve_forever()

	The client gets the image and saves it to a file::

	import xmlrpclib

	proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
	handle = open("fetched_python_logo.jpg", "w")
	handle.write(proxy.python_logo().data)
	handle.close()

	.. _fault-objects:

	Fault Objects
	-------------

	A :class:`Fault` object encapsulates the content of an XML-RPC fault tag. Fault
	objects have the following members:


	.. attribute:: Fault.faultCode

	A string indicating the fault type.


	.. attribute:: Fault.faultString

	A string containing a diagnostic message associated with the fault.

	In the following example we're going to intentionally cause a :exc:`Fault` by
	returning a complex type object. The server code::

	from SimpleXMLRPCServer import SimpleXMLRPCServer

	# A marshalling error is going to occur because we're returning a
	# complex number
	def add(x,y):
	return x+y+0j

	server = SimpleXMLRPCServer(("localhost", 8000))
	print("Listening on port 8000...")
	server.register_function(add, 'add')

	server.serve_forever()

	The client code for the preceding server::

	import xmlrpclib

	proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
	try:
	proxy.add(2, 5)
	except xmlrpclib.Fault, err:
	print("A fault occured")
	print("Fault code: %d" % err.faultCode)
	print("Fault string: %s" % err.faultString)



	.. _protocol-error-objects:

	ProtocolError Objects
	---------------------

	A :class:`ProtocolError` object describes a protocol error in the underlying
	transport layer (such as a 404 'not found' error if the server named by the URI
	does not exist). It has the following members:


	.. attribute:: ProtocolError.url

	The URI or URL that triggered the error.


	.. attribute:: ProtocolError.errcode

	The error code.


	.. attribute:: ProtocolError.errmsg

	The error message or diagnostic string.


	.. attribute:: ProtocolError.headers

	A dict containing the headers of the HTTP/HTTPS request that triggered the
	error.

	In the following example we're going to intentionally cause a :exc:`ProtocolError`
	by providing an invalid URI::

	import xmlrpclib

	# create a ServerProxy with an invalid URI
	proxy = xmlrpclib.ServerProxy("http://invalidaddress/")

	try:
	proxy.some_method()
	except xmlrpclib.ProtocolError, err:
	print("A protocol error occured")
	print("URL: %s" % err.url)
	print("HTTP/HTTPS headers: %s" % err.headers)
	print("Error code: %d" % err.errcode)
	print("Error message: %s" % err.errmsg)

	MultiCall Objects
	-----------------

	In http://www.xmlrpc.com/discuss/msgReader%241208, an approach is presented to
	encapsulate multiple calls to a remote server into a single request.


	.. class:: MultiCall(server)

	Create an object used to boxcar method calls. server is the eventual target of
	the call. Calls can be made to the result object, but they will immediately
	return ``None``, and only store the call name and parameters in the
	:class:`MultiCall` object. Calling the object itself causes all stored calls to
	be transmitted as a single ``system.multicall`` request. The result of this call
	is a :term:`generator`; iterating over this generator yields the individual
	results.

	A usage example of this class follows. The server code ::

	from SimpleXMLRPCServer import SimpleXMLRPCServer

	def add(x,y):
	return x+y

	def subtract(x, y):
	return x-y

	def multiply(x, y):
	return x*y

	def divide(x, y):
	return x/y

	# A simple server with simple arithmetic functions
	server = SimpleXMLRPCServer(("localhost", 8000))
	print("Listening on port 8000...")
	server.register_multicall_functions()
	server.register_function(add, 'add')
	server.register_function(subtract, 'subtract')
	server.register_function(multiply, 'multiply')
	server.register_function(divide, 'divide')
	server.serve_forever()

	The client code for the preceding server::

	import xmlrpclib

	proxy = xmlrpclib.ServerProxy("http://localhost:8000/")
	multicall = xmlrpclib.MultiCall(proxy)
	multicall.add(7,3)
	multicall.subtract(7,3)
	multicall.multiply(7,3)
	multicall.divide(7,3)
	result = multicall()

	print("7+3=%d, 7-3=%d, 7*3=%d, 7/3=%d" % tuple(result))


	Convenience Functions
	---------------------


	.. function:: boolean(value)

	Convert any Python value to one of the XML-RPC Boolean constants, ``True`` or
	``False``.


	.. function:: dumps(params[, methodname[, methodresponse[, encoding[, allow_none]]]])

	Convert params into an XML-RPC request. or into a response if methodresponse
	is true. params can be either a tuple of arguments or an instance of the
	:exc:`Fault` exception class. If methodresponse is true, only a single value
	can be returned, meaning that params must be of length 1. encoding, if
	supplied, is the encoding to use in the generated XML; the default is UTF-8.
	Python's :const:`None` value cannot be used in standard XML-RPC; to allow using
	it via an extension, provide a true value for allow_none.


	.. function:: loads(data[, use_datetime])

	Convert an XML-RPC request or response into Python objects, a ``(params,
	methodname)``. params is a tuple of argument; methodname is a string, or
	``None`` if no method name is present in the packet. If the XML-RPC packet
	represents a fault condition, this function will raise a :exc:`Fault` exception.
	The use_datetime flag can be used to cause date/time values to be presented as
	:class:`datetime.datetime` objects; this is false by default. Note that even if
	you call an XML-RPC method with :class:`datetime.date` or :class:`datetime.time`
	objects, they are converted to :class:`DateTime` objects internally, so only
	:class:`datetime.datetime` objects will be returned.


	.. _xmlrpc-client-example:

	Example of Client Usage
	-----------------------

	::

	# simple test program (from the XML-RPC specification)
	from xmlrpclib import ServerProxy, Error

	# server = ServerProxy("http://localhost:8000") # local server
	server = ServerProxy("http://betty.userland.com")

	print(server)

	try:
	print(server.examples.getStateName(41))
	except Error as v:
	print("ERROR", v)

	To access an XML-RPC server through a proxy, you need to define a custom
	transport. The following example shows how:

	.. Example taken from http://lowlife.jp/nobonobo/wiki/xmlrpcwithproxy.html

	::

	import xmlrpclib, httplib

	class ProxiedTransport(xmlrpclib.Transport):
	def set_proxy(self, proxy):
	self.proxy = proxy
	def make_connection(self, host):
	self.realhost = host
	h = httplib.HTTP(self.proxy)
	return h
	def send_request(self, connection, handler, request_body):
	connection.putrequest("POST", 'http://%s%s' % (self.realhost, handler))
	def send_host(self, connection, host):
	connection.putheader('Host', self.realhost)

	p = ProxiedTransport()
	p.set_proxy('proxy-server:8080')
	server = xmlrpclib.Server('http://time.xmlrpc.com/RPC2', transport=p)
	print(server.currentTime.getCurrentTime())


	Example of Client and Server Usage
	----------------------------------

	See :ref:`simplexmlrpcserver-example`.