Liferay Vaadin bootstrap Content Encoding Error - liferay

Question

I'm trying to convert our Vaadin porlets to serve the theme, widgetset etc from the portlets own web application rather that from the ROOT (Liferay) application but am hitting a content encoding problem.
I've added to the portlet.xml
<init-param>
<name>vaadin.resources.path</name>
<value>PORTLET_CONTEXT</value>
</init-param>
and to the web.xml
<servlet>
<servlet-name>VaadinServlet</servlet-name>
<servlet-class>com.vaadin.server.VaadinServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>VaadinServlet</servlet-name>
<url-pattern>/VAADIN/*</url-pattern>
</servlet-mapping>
The portlets wont start as they can't load {WEB_APP}/VAADIN/vaadinBootstrap.js?v.7.7.7
If I try and load the js file manually in Firefox the error I get is
Content Encoding Error
The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression.
Please contact the website owners to inform them of this problem.
If I use wget to load the URL it works perfectly and downloads the bootstrap.js file.
We have Liferay 6.2EE and Vaadin 7.7.7

Answer 1

I've managed to solve this. It appears that VaadinServlet checks for the gzip header, and if found returns the .gz version of the file. This was subsequently getting gzipped again by the HTTP server. The solution was to override the Servlet and disable the gzip code.
<servlet>
<servlet-name>VaadinServlet</servlet-name>
<servlet-class>com.foo.MyVaadinServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>VaadinServlet</servlet-name>
<url-pattern>/VAADIN/*</url-pattern>
</servlet-mapping>
Then created a custom Servlet like this where I always return false for allowServePrecompressedResource.
package com.foo;
import javax.servlet.http.HttpServletRequest;
import com.vaadin.server.VaadinServlet;
public class MyVaadinServlet extends VaadinServlet {
#Override
protected boolean allowServePrecompressedResource(HttpServletRequest request, String url)
{
return false;
}
}