Recipe 18.12 Writing an XML-RPC Client

18.12.1 Problem

You want to write a client for an XML-RPC service.

18.12.2 Solution

Use the XMLRPC::Lite module from the SOAP-Lite distribution:

use XMLRPC::Lite;

$server = XMLRPC::Lite->proxy("http://server.example.com/path");
$result = $server->call('ClassName.handler', @ARGS);
die $call->faultstring if $call->fault;
print $call->result;

18.12.3 Discussion

A single XML-RPC server may run many services, differentiated by their method name: ClassName.handler corresponds to ClassName->handler on the server side; A.B.method corresponds to A::B->method; and a call to handler corresponds to main->handler.

The proxy is the actual URL of the server. If you're using a CGI server, the proxy method looks something like this:

$server->proxy("http://server.example.com/path/to/server.cgi")

There are three ways to invoke remote methods. The first way is to use the call method on your XMLRPC::Lite object. The first argument to call is the remote method name, and the remaining arguments are parameters for the remote method:

$returned = $server
         -> call("getRecordByNumber", 12, { format => "CSV" })
         -> result;

The second way to invoke a remote method is to call that method on the XMLRPC::Lite object. This works only when the remote method name isn't the same as a method provided by the XMLRPC::Lite object. For example:

$returned = $server
         -> getRecordByNumber(12, { format => "CSV" })
         -> result;

The last way to invoke a remote method is with autodispatch, turning unrequired function calls and method invocations in your Perl program into XML-RPC requests. Enable autodispatch with:

use XMLRPC::Lite +autodispatch =>
  proxy => "http://server.example.com/path";

$returned = getRecordByNumber(12, { format => "CSV" });

A critical difference between autodispatch and the other styles is that autodispatch automatically decodes the result into a Perl value for you. When you use an XMLRPC::Lite object, you must explicitly invoke the result method to decode the XML-RPC response into a Perl value.