Enhancing your GWT Application with the UrlRewriteFilter

Last week, I spent some time trying to change the location of my cache/nocache HTML files in my GWT project. I started the project with the gwt-maven-plugin's archetype. The message I posted to the gwt-maven Google Group is below.

Rather than having my application's HTML file in src/main/java/com/mycompany/Application.html, I'd like to move it to src/main/webapp/index.html. I tried copying the HTML and adding the following to my index.html, but no dice:

<meta name="gwt:module" content="com.mycompany.Application"/>

Is this possible with the gwt-maven-plugin? I'd like to have my main HTML and CSS at the root of my application.

The good news is I figured out a solution using the UrlRewriteFilter that 1) allows hosted mode to work as usual and 2) allows your app to be served up from the root URL (/ instead of /com.company.Module/Application.html). Here's the urlrewrite.xml that makes it all possible.

<?xml version="1.0" encoding="UTF-8"?><!DOCENGINE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 3.0//EN""http://tuckey.org/res/dtds/urlrewrite3.0.dtd"><urlrewrite><rule><from>^/$</from><to type="forward" last="true">/com.mycompany.app.Application/Application.html</to></rule><rule><from>/index.html</from><to type="forward" last="true">/com.mycompany.app.Application/Application.html</to></rule><-- This last rule is necessary for JS and CSS files --><rule><from>^/(.*)\.(.*)$</from><to type="forward">/com.mycompany.app.Application/$1.$2</to></rule></urlrewrite>

If you're using the gwt-maven plugin, this file goes in src/main/webapp/WEB-INF. In addition, you'll need to add the following to your web.xml.

<filter><filter-name>rewriteFilter</filter-name><filter-class>org.tuckey.web.filters.urlrewrite.UrlRewriteFilter</filter-class></filter><filter-mapping><filter-name>rewriteFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>

Finally, add the UrlRewriteFilter dependency in your pom.xml:

<dependency><groupId>org.tuckey</groupId><artifactId>urlrewritefilter</artifactId><version>3.1.0</version></dependency>

Please let me know if you have any questions.

Update:Jeff posted an alternative configuration that allows you to eliminate the last rule in urlrewrite.xml, as well as use the beloved mvn jetty:run command. To use cleaner WAR packaging and the Jetty plugin, add the following to your pom.xml:

<plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-war-plugin</artifactId><configuration><webappDirectory>
            ${project.build.directory}/${project.build.finalName}/com.mycompany.app.Application</webappDirectory></configuration></plugin><plugin><groupId>org.mortbay.jetty</groupId><artifactId>maven-jetty-plugin</artifactId><version>6.1.14</version><configuration><webAppConfig><contextPath>/</contextPath><baseResource implementation="org.mortbay.resource.ResourceCollection"><resourcesAsCSV>
                    ${basedir}/src/main/webapp,
                    ${project.build.directory}/${project.build.finalName}/com.mycompany.app.Application</resourcesAsCSV></baseResource></webAppConfig><scanIntervalSeconds>3</scanIntervalSeconds><scanTargets><scanTarget>${basedir}/src/main/resources</scanTarget><scanTarget>${basedir}/src/main/webapp/WEB-INF</scanTarget><scanTarget>
                ${project.build.directory}/${project.build.finalName}/com.mycompany.app.Application</scanTarget></scanTargets></configuration></plugin>

Then you can trim your urlrewrite.xml down to:

<urlrewrite><rule><from>^/$</from><to type="forward" last="true">/Application.html</to></rule><rule><from>/index.html</from><to type="forward" last="true">/Application.html</to></rule></urlrewrite>

Of course, you could also change the welcome-file in your web.xml or use index.html and the <meta http-equiv="REFRESH"> option. Personally, I have so much affection for the UrlRewriteFilter that I like having it in my project. I'm sure I'll need it someday.

Thanks Jeff!