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How to use SOAP Compression using JAX-RPC

· 3 min read

HTTP compression has improved a lot the download time of content from servers. In the context of Web Service it could be very interesting to also use HTTP compression to improve the network traffic. Firs, I am explaining how to compress a SOAP response when you have a Web Service running in Oracle Containers for J2EE (OC4J) using a generic servlet filter. I have to give credit to http://www.thomas-bayer.com/ since he has created the Filter and documented how to do such thing using Axis. 

So you can take a look to the following article for more details, you can read the 2 following article, or jump to the next paragraph that explains how to configure your JAX-RPC based service to send compressed HTTP response.

In this sample I am showing how to compress the SOAP response using a servlet filter, it is also possible to use some other Oracle infrastructure element to achieve that such as Oracle HTTP Server/Apache, or Oracle Webcache.

1- Install the compression filter library in your application​

Download the compression filter library 2wayfilter-1.2.jar and copy it into the Web application's WEB-INF/lib folder

2- Configure your application to use the filter​

The configuration of a servlet filter is done using the web.xml where you reference which servlet or URL will be using the filter. As you may knowin JAX-RPC, the HTTP endpoint of a service are exposed as servlet and defined in the web.xml. You can choose to compress all the endpoint/URL or create a new servlet mapping, that will become a new SOAP endpoint and only compress this one. If you take the option of creating a new endpoint keep in mind that it will not be added to the WSDL automatically, so the client application will have to point explicitly to the compressed endpoint URL to take benefits of it.

<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
  version="2.4">
  <servlet>
    <description>Web Service CustomerServiceSoapHttpPort</description>
    <display-name>Web Service CustomerServiceSoapHttpPort</display-name>
    <servlet-name>CustomerServiceSoapHttpPort</servlet-name>
    <servlet-class>demo.oracle.CustomerServiceImpl</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>CustomerServiceSoapHttpPort</servlet-name>
    <url-pattern>CustomerServiceSoapHttpPort</url-pattern>
  </servlet-mapping>

  <!-- New servlet mapping to handle compressed SOAP Messages -->
  <servlet-mapping>
    <servlet-name>CustomerServiceSoapHttpPort</servlet-name>
    <url-pattern>CompressedCustomerServiceSoapHttpPort</url-pattern>
  </servlet-mapping>


  <!-- Filter definition with mapping on the compressed endpoint -->
  <filter>
    <filter-name>2WayFilter</filter-name>
    <filter-class>com.osmoticweb.gzipfilter.GZIP2WayFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>2WayFilter</filter-name>
    <url-pattern>CompressedCustomerServiceSoapHttpPort</url-pattern>
  </filter-mapping>

</web-app>

You can now package and deploy your application.

3- Create & Invoke the service​

In this basic configuration you have only changed the servlet that is the HTTP endpoint of your service. So the compressed endpoint is not present in the WSDL, but you can use any of the URL to create your proxy.

When you have created your proxy, if you want to access the endpoint that will return the compressed response you must be sure that you are calling the correct endpoint. You can set the endpoint using the setEndpoint method, of your Web Service client.

This is it!

I will in a next post explain how you can using the Oracle Web Service client API send a compressed request that will have to be uncompressed on the server using the same filter.