Intercepting HTTP Parameters on an Axis Endpoint in Mule

I've been trying to write an interceptor for Mule 1.4.3 container to intercept a message that contains a username and password for authentication. The interceptor is to act as a Permission Check interceptor described in the Mule docs.

I was able to come up with an approach that might fit my needs, although there could very well likely be a better approach.

My Mule 1.4.3 configuration is setup to take an HTTP request for an Axis endpoint. The HTTP request has a user and a password parameter. I have an interceptor, EchoInterceptor, that is going to look for the user and password parameters:

<mule-configuration id="Mule_Echo_Parameters_Axis" version="1.0">  
  <transformers>
    <transformer name="HttpRequestToSoapRequest"
     className="org.mule.providers.soap.transformers.HttpRequestToSoapRequest"/>
  </transformers>
  <model name="echoAuth">
    <mule-descriptor name="EchoAuth" implementation="EchoAuth">
      <inbound-router>
        <endpoint address="axis:http://localhost:65081/services"
                  transformers="HttpRequestToSoapRequest" />
      </inbound-router>
      <interceptor className="EchoInterceptor"/>
    </mule-descriptor>
  </model>
</mule-configuration>

The EchoAuth class has an echo method whose invocation I want to intercept. The method simply echos the parameters its given. An HTTP request to the Axis endpoint looks like:

http://localhost:65081/services/EchoAuth?method=echo&user=Costanza&password=bosco

The interceptor class:

import java.util.Properties;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.mule.umo.Invocation;
import org.mule.umo.UMOException;
import org.mule.umo.UMOInterceptor;
import org.mule.umo.UMOMessage;
import org.mule.util.PropertiesUtils;

public class EchoInterceptor implements UMOInterceptor {
    
    private final Log logger = LogFactory.getLog(this.getClass());
    
    @Override
    public UMOMessage intercept(Invocation invocation) throws UMOException {
        
        logger.info("Intercepted method invocation.");
        
        UMOMessage incomingMessage = invocation.getMessage();                       
        logger.info("Incoming message: " + incomingMessage.toString());
                     
        String request = incomingMessage.getProperty("http.request").toString();
        int i = request.indexOf('?');
        String query = request.substring(i + 1);
        logger.info("HTTP request query string: " + query);
        
        // following example in Mule's HTTPRequestToSoapRequest class
        Properties p = PropertiesUtils.getPropertiesFromQueryString(query);        
        String user = p.getProperty("user");
        String password = p.getProperty("password");
        logger.info("Query string parameter 'user': " + user);
        logger.info("Query string parameter 'password': " + password);
        
        UMOMessage resultingMessage = invocation.execute();
        logger.info("Returning resulting message: " + resultingMessage.toString());
        
        return resultingMessage;
    }
}

The results in my mule.log, with a lot of the clutter omitted:

EchoInterceptor: Incoming message: org.mule.providers.soap.axis.AxisMessageAdapter
/org.mule.providers.soap.axis.AxisMessageAdapter... properties={
http.version=HTTP/1.1
method=public abstract java.lang.String AuthService.echo(java.lang.String,java.lang.String)
MULE_ORIGINATING_ENDPOINT=endpoint.http.localhost.65081.services
http.method=GET
http.request=/services/EchoAuth?method=echo&user=Costanza&password=bosco
}}
EchoInterceptor: HTTP request query string: method=echo&user=Costanza&password=bosco
EchoInterceptor: Query string parameter 'user': Costanza
EchoInterceptor: Query string parameter 'password': bosco
EchoAuth: Received user: Costanza
EchoAuth: Received password: bosco
EchoAuth: Authentication: Costanza/bosco
EchoInterceptor: Returning resulting message: 
...
http.request=/services/EchoAuth?method=echo&user=Costanza&password=bosco
http.method=GET
...

In my real-world project, I need to send the user and password off to a
service for authentication, and halt processing. The interceptor doc lists a couple of methods for doing so I need to investigate further.