Allowing or denying self registration with grails-acegi plugin

The grails-acegi-0.2 plugin is great - it adds login, user management, and user registration capabilities to your application in seconds. However, I'm building a web application where I want to be able to let the deployment team decide whether users can register themselves or alternatively, have an administrator create users. I want provide these settings without the deployment unit (the WAR file) having to be modified.

I currently have a properties file for each server (DEV, STAGE, PROD) which defines properties specific to the environment - such as the email server and username/password etc. In this properties file, I also have application settings which are relevant to that environment. So, this is a good place to define a property:

myapp.registration.enabled=false

Grails has an excellent configuration strategy, and in my applications Config.groovy all I have to do is specify the external config locations:

grails.config.locations = ["file:${System.getProperty('myapp.properties')}"]

I've referenced a system property, so anyone deploying my application just needs to use the -D jvm option - when running with grails all we have to do is:

grails -Dmyapp.properties=/server/env/prod/server.properties

Now I just need to modify the RegistrationController.groovy to check this property:

  def index = {
    //if logon user.
    if(authenticateService.userDomain()!=null){
      log.info("${authenticateService.userDomain()} user hit the register page")
      redirect(action:"show")
      return
    }

    if(!(grailsApplication.config.jtchat.registration.enabled=='false')) {
        def person = new Person()
        person.properties = params
        return ['person': person]
    } else {
        redirect(uri:'/')
    }
  }

And that's it. An easy way to provide settings to an application without modifying the WAR. Grails rocks!