Override a template method in scaffolded controllers

Question

I have a Grails project where I use heavily customized scaffolding templates to add a beforeUpdate template method to update so that I can easily customize scaffolded Controller's without having to generate and then edit each controller separately.

Unfortunately this doesn't work and only beforeUpdate from scaffolding gets called. I suspect it has to do with the code generation used by Groovy to inject the scaffolding code into the actual Controller, but I can't find any confirmation.

What I'm asking is either a solution to the problem or an explanation for why it doesn't work.

Here is the scaffolding code:

def beforeUpdate = {
    println "beforeUpdate from scaffold"
}

def update() {
    // call before update hook
    beforeUpdate()

    def ${propertyName} = ${className}.get(params.id)
    if (!${propertyName}) {
        flash.message = message(code: 'default.not.found.message', args: [message(code: '${domainClass.propertyName}.label', default: '${className}'), params.id])
        redirect(action: "list")
        return
    }
    [...]

and the scaffolded controller code (which is not called, while I believe it should):

class CalendarController {
    static scaffold = Calendar

    def beforeUpdate = {
            println "beforeUpdate from controller"
    }
}

I have already tried grails clean ;-)

UPDATE

I have eventually realized that this is simply impossibile due to how the Grails scaffolding is designed. Closing.

To "close" this question, you should add your own answer and then mark it as accepted. — madth3, Feb 19 '13 at 01:23

score 1 · Answer 1 · edited May 23 '17 at 12:05

You have a similar problem to this question - essentially the way scaffolding works the scaffolding template generates a separate class which the "real" controller delegates to. So if you want the generated controller to call methods on the real controller you can't use this, you need to get a reference to the real controller object.

To cut a long story short, use

GrailsWebUtil.getControllerFromRequest(request).beforeUpdate()

instead of just

beforeUpdate()

def update() {
    // call before update hook
    def realController = GrailsWebUtil.getControllerFromRequest(request)
    if(realController.hasProperty('beforeUpdate') &&
         realController.beforeUpdate instanceof Closure) {
      realController.beforeUpdate()
    } else {
      this.beforeUpdate()
    }

    def ${propertyName} = ${className}.get(params.id)
    if (!${propertyName}) {
        flash.message = message(code: 'default.not.found.message', args: [message(code: '${domainClass.propertyName}.label', default: '${className}'), params.id])
        redirect(action: "list")
        return
    }
    [...]

score 0 · Accepted Answer · answered Jun 04 '13 at 06:34

0

I have eventually realized that this is simply impossibile due to how the Grails scaffolding is designed: by dynamically copying/creating methods into the scaffolded controllers and not using inheritance.

answered Jun 04 '13 at 06:34

unicoletti

204
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Override a template method in scaffolded controllers

2 Answers2