11.20 xmlrpclib -- XML-RPC client access

11.20 xmlrpclib -- XML-RPC client access

New in version 2.2.

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]]])

A 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 SafeTransport instance for https: URLs and an internal HTTP Transport instance otherwise. The optional third argument is an encoding, by default UTF-8. The optional fourth argument is a debugging flag.

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.

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

boolean The True and False constants
integers Pass in directly
floating-point numbers Pass in directly
strings Pass in directly
arrays Any Python sequence type containing conformable elements. Arrays are returned as lists
structures A Python dictionary. Keys must be strings, values may be any conformable type.
dates in seconds since the epoch; pass in an instance of the DateTime wrapper class
binary data pass in an instance of the Binary wrapper class

Name	Meaning
`boolean`	The `True` and `False` constants
`integers`	Pass in directly
`floating-point numbers`	Pass in directly
`strings`	Pass in directly
`arrays`	Any Python sequence type containing conformable elements. Arrays are returned as lists
`structures`	A Python dictionary. Keys must be strings, values may be any conformable type.
`dates`	in seconds since the epoch; pass in an instance of the `DateTime` wrapper class
`binary data`	pass in an instance of the `Binary` wrapper class

This is the full set of data types supported by XML-RPC. Method calls may also raise a special Fault instance, used to signal XML-RPC server errors, or ProtocolError used to signal an error in the HTTP/HTTPS transport layer.

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; 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 Binary wrapper class described below.

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

See Also:

XML-RPC HOWTO: A good description of XML operation and client software in several languages. Contains pretty much everything an XML-RPC client developer needs to know.

XML-RPC-Hacks page: Extensions for various open-source libraries to support instrospection and multicall.

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