| :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`. |
| |
| .. versionchanged:: 3.4.3 |
| |
| For https URIs, :mod:`xmlrpc.client` now performs all the necessary |
| certificate and hostname checks by default |
| |
| .. class:: ServerProxy(uri, transport=None, encoding=None, verbose=False, \ |
| allow_none=False, use_datetime=False, \ |
| use_builtin_types=False, *, context=None) |
| |
| .. 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. If an HTTPS url is provided, *context* may |
| be :class:`ssl.SSLContext` and configures the SSL settings of the underlying |
| HTTPS connection. |
| |
| 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`. |
| |
| .. versionchanged:: 3.4.3 |
| Added the *context* argument. |
| |
| |
| .. 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) |