Add methods to controllers

问题

In a Grails application I would like to add a foo() method to all my controller classes. I know that I can do this inside a plugin's doWithDynamicMethods closure using code like:

application.controllerClasses.toList()*.metaClass*.foo = { println 'foo called' }

However, I don't want to create a plugin just for this purpose. Is there anywhere else I can do this. I suspect it might be possible within the init closure of BootStrap.groovy, but I don't know how to get access to the GrailsApplication instance in this closure.

Thanks, Don

回答1:

def grailsApplication = org.codehaus.groovy.grails.commons.ApplicationHolder.application

回答2:

The question was asked a long time ago, so my answer might not have been possible back then - but now it's April 2014. This code shows the most straightforward way of adding a method to all your controllers (from within BootStrap.init):

grailsApplication.controllerClasses.each { controllerClass ->
    if (controllerClass.clazz.name.contains("org.idurkan.foo")) {
        controllerClass.metaClass.respondError = { String message, int status = 404 ->
            response.status = status
            render([errorMessage: message] as JSON)
        }
    }
}

In BootStrap.groovy, inject grailsApplication like this: def grailsApplication
Make a call like mine above, substituting your own package name - to avoid messing around with plugins' classes.
Now in any controller you can use the repondError closure (invoke it like a method).

Note this does not add an action! It's just a utility closure/method available in every controller.

回答3:

class BootStrap {
    def grailsApplication

    def init = { servletContext ->
        ...
    }
}

来源：https://stackoverflow.com/questions/1049418/add-methods-to-controllers

标签

grails

metaprogramming