mirror of https://github.com/python/cpython
570 lines
21 KiB
ReStructuredText
570 lines
21 KiB
ReStructuredText
:mod:`xmlrpc.client` --- XML-RPC client access
|
|
==============================================
|
|
|
|
.. module:: xmlrpc.client
|
|
: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 and Transport.
|
|
|
|
**Source code:** :source:`Lib/xmlrpc/client.py`
|
|
|
|
--------------
|
|
|
|
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.
|
|
|
|
|
|
.. warning::
|
|
|
|
The :mod:`xmlrpc.client` module is not secure against maliciously
|
|
constructed data. If you need to parse untrusted or unauthenticated data see
|
|
:ref:`xml-vulnerabilities`.
|
|
|
|
|
|
.. class:: ServerProxy(uri, transport=None, encoding=None, verbose=False, \
|
|
allow_none=False, use_datetime=False, \
|
|
use_builtin_types=False)
|
|
|
|
.. versionchanged:: 3.3
|
|
The *use_builtin_types* flag was added.
|
|
|
|
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_builtin_types* flag can be used to cause date/time values
|
|
to be presented as :class:`datetime.datetime` objects and binary data to be
|
|
presented as :class:`bytes` objects; this flag is false by default.
|
|
:class:`datetime.datetime` and :class:`bytes` objects may be passed to calls.
|
|
|
|
The obsolete *use_datetime* flag is similar to *use_builtin_types* but it
|
|
applies only to date/time values.
|
|
|
|
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):
|
|
|
|
.. tabularcolumns:: |l|L|
|
|
|
|
+---------------------------------+---------------------------------------------+
|
|
| 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` instance. |
|
|
+---------------------------------+---------------------------------------------+
|
|
| :const:`binary data` | Pass in an instance of the :class:`Binary` |
|
|
| | wrapper class or a :class:`bytes` instance. |
|
|
+---------------------------------+---------------------------------------------+
|
|
|
|
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 the xmlrpc client module currently does not marshal
|
|
instances of subclasses of built-in types.
|
|
|
|
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 bytes
|
|
via XML-RPC, use the :class:`bytes` class or 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.
|
|
|
|
`XML-RPC Specification <http://www.xmlrpc.com/spec>`_
|
|
The official specification.
|
|
|
|
`Unofficial XML-RPC Errata <http://effbot.org/zone/xmlrpc-errata.htm>`_
|
|
Fredrik Lundh's "unofficial errata, intended to clarify certain
|
|
details in the XML-RPC specification, as well as hint at
|
|
'best practices' to use when designing your own XML-RPC
|
|
implementations."
|
|
|
|
.. _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` attribute:
|
|
|
|
|
|
.. 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
|
|
than 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.
|
|
|
|
|
|
A working example follows. The server code::
|
|
|
|
from xmlrpc.server 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 xmlrpc.client
|
|
|
|
proxy = xmlrpc.client.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`
|
|
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 rich comparison
|
|
and :meth:`__repr__` methods.
|
|
|
|
A working example follows. The server code::
|
|
|
|
import datetime
|
|
from xmlrpc.server import SimpleXMLRPCServer
|
|
import xmlrpc.client
|
|
|
|
def today():
|
|
today = datetime.datetime.today()
|
|
return xmlrpc.client.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 xmlrpc.client
|
|
import datetime
|
|
|
|
proxy = xmlrpc.client.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 bytes 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 a :class:`bytes` object.
|
|
|
|
:class:`Binary` objects have the following methods, supported mainly for
|
|
internal use by the marshalling/unmarshalling code:
|
|
|
|
|
|
.. method:: Binary.decode(bytes)
|
|
|
|
Accept a base64 :class:`bytes` object 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.
|
|
|
|
The encoded data will have newlines every 76 characters as per
|
|
`RFC 2045 section 6.8 <http://tools.ietf.org/html/rfc2045#section-6.8>`_,
|
|
which was the de facto standard base64 specification when the
|
|
XML-RPC spec was written.
|
|
|
|
It also supports certain of Python's built-in operators through :meth:`__eq__`
|
|
and :meth:`__ne__` methods.
|
|
|
|
Example usage of the binary objects. We're going to transfer an image over
|
|
XMLRPC::
|
|
|
|
from xmlrpc.server import SimpleXMLRPCServer
|
|
import xmlrpc.client
|
|
|
|
def python_logo():
|
|
with open("python_logo.jpg", "rb") as handle:
|
|
return xmlrpc.client.Binary(handle.read())
|
|
|
|
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 xmlrpc.client
|
|
|
|
proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
|
|
with open("fetched_python_logo.jpg", "wb") as handle:
|
|
handle.write(proxy.python_logo().data)
|
|
|
|
.. _fault-objects:
|
|
|
|
Fault Objects
|
|
-------------
|
|
|
|
A :class:`Fault` object encapsulates the content of an XML-RPC fault tag. Fault
|
|
objects have the following attributes:
|
|
|
|
|
|
.. 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 xmlrpc.server 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 xmlrpc.client
|
|
|
|
proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
|
|
try:
|
|
proxy.add(2, 5)
|
|
except xmlrpc.client.Fault as err:
|
|
print("A fault occurred")
|
|
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 attributes:
|
|
|
|
|
|
.. 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 xmlrpc.client
|
|
|
|
# create a ServerProxy with an URI that doesn't respond to XMLRPC requests
|
|
proxy = xmlrpc.client.ServerProxy("http://google.com/")
|
|
|
|
try:
|
|
proxy.some_method()
|
|
except xmlrpc.client.ProtocolError as err:
|
|
print("A protocol error occurred")
|
|
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
|
|
-----------------
|
|
|
|
The :class:`MultiCall` object provides a way 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 xmlrpc.server 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 xmlrpc.client
|
|
|
|
proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
|
|
multicall = xmlrpc.client.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:: dumps(params, methodname=None, methodresponse=None, encoding=None, allow_none=False)
|
|
|
|
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=False, use_builtin_types=False)
|
|
|
|
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_builtin_types* flag can be used to cause date/time values to be
|
|
presented as :class:`datetime.datetime` objects and binary data to be
|
|
presented as :class:`bytes` objects; this flag is false by default.
|
|
|
|
The obsolete *use_datetime* flag is similar to *use_builtin_types* but it
|
|
applies only to date/time values.
|
|
|
|
.. versionchanged:: 3.3
|
|
The *use_builtin_types* flag was added.
|
|
|
|
|
|
.. _xmlrpc-client-example:
|
|
|
|
Example of Client Usage
|
|
-----------------------
|
|
|
|
::
|
|
|
|
# simple test program (from the XML-RPC specification)
|
|
from xmlrpc.client 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 xmlrpc.client, http.client
|
|
|
|
class ProxiedTransport(xmlrpc.client.Transport):
|
|
def set_proxy(self, proxy):
|
|
self.proxy = proxy
|
|
def make_connection(self, host):
|
|
self.realhost = host
|
|
h = http.client.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 = xmlrpc.client.Server('http://time.xmlrpc.com/RPC2', transport=p)
|
|
print(server.currentTime.getCurrentTime())
|
|
|
|
|
|
Example of Client and Server Usage
|
|
----------------------------------
|
|
|
|
See :ref:`simplexmlrpcserver-example`.
|
|
|
|
|
|
.. rubric:: Footnotes
|
|
|
|
.. [#] This approach has been first presented in `a discussion on xmlrpc.com
|
|
<http://web.archive.org/web/20060624230303/http://www.xmlrpc.com/discuss/msgReader$1208?mode=topic>`_.
|
|
.. the link now points to webarchive since the one at
|
|
.. http://www.xmlrpc.com/discuss/msgReader%241208 is broken (and webadmin
|
|
.. doesn't reply)
|