Getting Sitemesh running on Google App Engine

I’ve been having a ball playing with Gaelyk for developing Google App Engine applications in Groovy. One thing that Gaelyk lacks (for now! It’s only 0.3.x) is any kind of layout engine like Sitemesh. No probs, just add then the Sitemesh filter to your web.xml and you’re off, right?

    <filter>
        <filter-name>sitemesh</filter-name>
        <filter-class>com.opensymphony.sitemesh.webapp.SiteMeshFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

Well that would be wonderful! However Sitemesh 2.4.1 has some integration points with JNDI that will bring you a world of hurt (Error 500) along with a description in your app engine logs. It will work locally, but fail once deployed. For later googlers, here’s the strings from the appengine logs:

Error for /
java.lang.NoClassDefFoundError: javax.naming.InitialContext is a restricted class. Please see the Google App Engine developer's guide for more details.
    at com.google.apphosting.runtime.security.shared.stub.javax.naming.InitialContext.(InitialContext.java)
    at com.opensymphony.module.sitemesh.Factory.getEnvEntry(Factory.java:91)

Fortuntely some kind soul has documented the fix for that Factory class already. Followed those instructions and I was in business.

Now, onto some more DataStore experiments with Gaelyk…