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Chapter 137. XmlRpc

XmlRpc Component

Available as of Camel 2.11
This component provides a dataformat for xml, which allows serialization and deserialization of request messages and response message using Apache XmlRpc's bindary dataformat. You can also invoke the XMLRPC Service through the camel-xmlrpc producer.
Maven users will need to add the following dependency to their pom.xml for this component: 
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-xmlrpc</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

XmlRpc Overview

It's a spec and a set of implementations that allow software running on disparate operating systems, running in different environments to make procedure calls over the Internet.
It's remote procedure calling using HTTP as the transport and XML as the encoding. XML-RPC is designed to be as simple as possible, while allowing complex data structures to be transmitted, processed and returned.
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>

URI format

xmlrpc://serverUri[?options]

Options

Property Default Description
basicEncoding null Sets the encoding for basic authentication, null means UTF-8 is chosen.
basicUserName null The user name for basic authentication.
basicPassword null The password for basic authentication.
clientConfigurer null The reference id of the XmlRpcClient configurer which implement the interface of XmlRpcClientConfigurer to setup the XmlRpcClient as user wants. The value should be start with "#" such as "#myConfigurer"
connectionTimeout 0 Set the connection timeout in milliseconds, 0 is to disable it
contentLengthOptional false whether a "Content-Length" header may be omitted. The XML-RPC specification demands, that such a header be present.
enabledForExceptions false whether the response should contain a "faultCause" element in case of errors. The "faultCause" is an exception, which the server has trapped and written into a byte stream as a serializable object.
enabledForExtensions false whether extensions are enabled. By default, the client or server is strictly compliant to the XML-RPC specification and extensions are disabled.
encoding null Sets the requests encoding, null means UTF-8 is chosen.
gzipCompressing false Whether gzip compression is being used for transmitting the request.
gzipRequesting false Whether gzip compression is being used for transmitting the request.
replyTimeout 0 Set the reply timeout in milliseconds, 0 is to disable it.
userAgent null The http user agent header to set when doing xmlrpc requests

Message Headers

Camel XmlRpc uses these headers.
Header Description
CamelXmlRpcMethodName The XmlRpc method name which will be use for invoking the XmlRpc server.

Using the XmlRpc data format

As the XmlRpc message could be request or response, when you use the XmlRpcDataFormat, you need to specify the dataformat is for request or not. 
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">

    <!-- we define the xml rpc data formats to be used -->
    <dataFormats>
        <xmlrpc id="xmlrpcRequest" request="true"/>
        <xmlrpc id="xmlrpcResponse" request="false"/>
    </dataFormats>

    <route>
        <from uri="direct:request"/>
        <marshal ref="xmlrpcRequest"/>
        <unmarshal>
           <xmlrpc request="true"/>
        </unmarshal>
        <to uri="mock:request" />
    </route>

    <route>
        <from uri="direct:response"/>
        <marshal>
            <xmlrpc request="false"/>
        </marshal>
        <unmarshal ref="xmlrpcResponse"/>
        <to uri="mock:response" />
    </route>
</camelContext>

Invoke XmlRpc Service from Client

To invoke the XmlRpc service, you need to specify the methodName on the message header and put the parameters into the message body like below code, then you can get the result message as you want. If the fault message is return, you should get an exception which cause if XmlRpcException. 
   String response = template.requestBodyAndHeader(xmlRpcServiceAddress, new Object[]{"me"}, XmlRpcConstants.METHOD_NAME, "hello", String.class);

How to configure the XmlRpcClient with Java code

camel-xmlrpc provides a pluggable strategy for configuring the XmlRpcClient used by the component, user just to implement the XmlRpcClientConfigurer interface and can configure the XmlRpcClient as he wants. The clientConfigure instance reference can be set through the uri option clientConfigure. 
import org.apache.xmlrpc.client.XmlRpcClient;
import org.apache.xmlrpc.client.XmlRpcClientConfigImpl;

public class MyClientConfigurer implements XmlRpcClientConfigurer {

    @Override
    public void configureXmlRpcClient(XmlRpcClient client) {
        // get the configure first
        XmlRpcClientConfigImpl clientConfig = (XmlRpcClientConfigImpl)client.getClientConfig();
        // change the value of clientConfig
        clientConfig.setEnabledForExtensions(true);
        // set the option on the XmlRpcClient
        client.setMaxThreads(10);
    }

}