Programmers Quotes

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"?>
<!DOCTYPE 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!

Earlier this week, I spent some time implementing GWTTestSuite to speed up my project’s build process. In Hudson, the project was taking around 15 minutes to build, locally it was only taking 5 minutes for mvn test. In IDEA, I could run all the tests in under a minute. While 15 minutes isn’t a long time for a build to execute, a co-worker expressed some concern:

Does Maven have to run GWT test and individual Java processes? (See target/gwtTest/*.sh) This arrangement and the overhead of JVM launches is another reason why builds take so long. As we add more GWT tests we are going to test that LinkedIn record for the slowest build ever.

After this comment, I started looking into GWTTestSuite using Olivier Modica’s blog entry as a guide. It was very easy to get things working in IDEA. However, when I’d run mvn test, I’d get the following error:

Error: java.lang.ClassCastException

No line numbers. No class information. Zilch. After comparing my project’s pom.xml with the one from the default gwt-maven archetype, I noticed the default used JUnit 4.1, while I had the latest-and-supposedly-greatest JUnit 4.4. Reverting to JUnit 4.4 fixed the problem. Now Hudson takes 3:15 to execute the build instead of 15 minutes.

The reason for this blog post is this doesn’t seem to be documented anywhere. Hopefully other developers will find this entry when googling for this issue.

Related to making GWT faster, I also added the following line to my Application.gwt.xml file:

<set-property name="user.agent" value="safari" />

This dropped the gwt:compile time from 1 minute to 25 seconds. As explained in the documentation, you can use the “user.agent” setting to only generate one JS file for your app instead of 4. The strange thing about adding this setting was I pretty much forgot about it since everything seemed to work fine on both Safari and Firefox. When I started testing things in IE6, I started seeing a lot of JavaScript errors. After debugging for an hour or so, I realized this setting was there, removed it, and everything started working great in all browsers.

Now if I could just figure out how to use safari-only for development, but remove the line when building the WAR. Suggestions welcome.