XML-RPC

From Wikipedia, the free encyclopedia

XML-RPC is a remote procedure call protocol which uses XML to encode its calls and HTTP as a transport mechanism. It is a very simple protocol, defining only a handful of data types and commands, and the entire description can be printed on two pages of paper. This is in stark contrast to most RPC systems, where the standards documents often run into the thousands of pages and require considerable software support in order to be used.

It was first created by Dave Winer of UserLand Software in 1998 with Microsoft. As new functionality was introduced, the standard evolved into what is now SOAP. However, some people still prefer XML-RPC to SOAP because of its simplicity, minimalism and ease of use.

1 Data types
2 Examples
3 See also
4 External links

[edit] Data types

Name	Tag Example	Description
array	<array> <data> <value><i4>1404</i4></value> <value><string>Something here</string></value> <value><i4>1</i4></value> </data> </array>	Array of values, storing no keys
base64	<base64>eW91IGNhbid0IHJlYWQgdGhpcyE=</base64>	Base 64-encoded binary data
boolean	<boolean>1</boolean>	Boolean logical value (0 or 1)
date/time	<dateTime.iso8601>19980717T14:08:55</dateTime.iso8601>	Date and time
double	<double>-12.53</double>	Double precision floating number
integer	<i4>42</i4> or <int>42</int>	Whole number, integer
string	<string>Hello world!</string>	String of characters. Must follow XML encoding.
struct	<struct> <member> <name>foo</name> <value><i4>1</i4></value> </member> <member> <name>bar</name> <value><i4>2</i4></value> </member> </struct>	Array of values, storing keys
nil	<nil/>	Discriminated null value; an XML-RPC extension

[edit] Examples

An example of a typical XML-RPC request would be:

<?xml version="1.0"?>
<methodCall>
  <methodName>examples.getStateName</methodName>
  <params>
    <param>
        <value><i4>40</i4></value>
    </param>
  </params>
</methodCall>

An example of a typical XML-RPC response would be:

<?xml version="1.0"?>
<methodResponse>
  <params>
    <param>
        <value><string>South Dakota</string></value>
    </param>
  </params>
</methodResponse>

A typical XML-RPC fault would be:

<?xml version="1.0"?>
<methodResponse>
  <fault>
    <value>
      <struct>
        <member>
          <name>faultCode</name>
          <value><int>4</int></value>
        </member>
        <member>
          <name>faultString</name>
          <value><string>Too many parameters.</string></value>
        </member>
      </struct>
    </value>
  </fault>
</methodResponse>