grails 2.0 - correct use of serverURL for production?

Question

Grails 2.0 changed with the way it uses grails.serverURL for development and test environments (as described in the manual). However, I've had several problems with serverURL in regard to production deployment on Tomcat. There seem to be several options for serverURL (production mode):

• (Added) this setting is just "smoke and mirrors", because Tomcat and Jetty have methods to control how the URL is handled for the App, down to the "App" level.

• Use it to specify the server (as is pointed out as a "TODO" in Config.groovy)

• Don't use it as indicated here by one of the Grails contributors, i.e. "It should always be safe to remove the serverURL property and let Grails generate urls relative to the current running app." It's not clear if this extends to production or not (when not generating emails).

• Use another method instead, namely grails.app.context, which is not documented in Grails 2.0 manual, but is described in certain references, here and here.

Can you please clarify the correct use of serverURL and app.context, both for Jetty and Tomcat (production mode)?

Thanks

Answer 1

So the basic idea of the grails.serverURL configuration parameter is to allow the createLink method to know what URL you want when creating absolute links. If no grails.serverURL configuration parameter is specified, it will default to http://localhost:8080 (unless server.port is specified, then 8080 will be whatever) ...

The application context tells Jetty/Tomcat to run the application in a different root. For example, specifying

grails.app.context="/myApp"

will set your application root to "/myApp". In production mode, the application context is handled by the web container and this directive is ignored. The choice to configure your production jetty or tomcat instances to run your application in a different context is entirely dependent on what your technical requirements are.

So the real thing to consider is, in your application are you creating a lot of absolute links in your GSPs where you need to define a "production" serverURL? If not, then you don't need to specify it; if you are, then you'll need to specify it.

As a personal preference, the first thing that I always do after creating a new grails project is go into the config and change the grails.app.context to "/" ... It makes mirroring a production environment much easier for me.

Hope this clears things up!

Answer 2

Good question! I was just looking for the correct way to get the actual serverURL without explicitly needing to configure it in Config.groovy (in a Grails 2.1 application).

Since Grails 2.0, there is a super-useful class called LinkGenerator that you can use virtually anywhere, for example in a Service:

import org.codehaus.groovy.grails.web.mapping.LinkGenerator

Class MyService {
    LinkGenerator grailsLinkGenerator

    String serverUrl() {
        // Generate: http://localhost:8080/link-generator
        grailsLinkGenerator.serverBaseURL
    }
}

Thanks to Mr. Haki for blogging about this!