Grails “render” renders the template

问题

In my Grails controller I'm responding to an AJAX call and using render to return the text:

def ajaxRandomPersonName = {
    def person = get a random person ...
    render "Name: ${person.name}"
}

The problem is that render renders the whole template. So instead of just rendering "Name: John" it renders all the icons, navigation, etc defined in the template. How do I get render to just render without the template?

I'm pretty much following Chapter 1 of "Grails in Action" (page 28) using Grails 1.1.1.

Follow up: Returning false per Rhysyngsun's suggestion has no impact. I also tried setting the template to null but it still renders the template:

def ajaxRandomPersonName = {
    def person = get a random person ...
    render (template:null, text:"Name: ${person.name}")
}

render has its heart bent on rendering it through the template no matter what I do.

Follow up 2: Parallel discussion on grails-user mailing list.

Follow up 3: Sample code: I paired down my code the bare minimum and it still exhibits the undesired template rendering.

controllers/PersonController.groovy:

class PersonController { 
    def index = { } 
    def home = { [message:"Hello"] } 

    def ajaxTest = { 
        println "ajaxTest called" 
        render text: "ajax message" 
    } 
}

views/person/home.gsp (view page for home method)

<html> 
<head> 
    <title>Home View</title> 
    <g:javascript library="prototype" /> 
</head> 
<body> 
    <p> 
        <g:remoteLink action="ajaxTest" update="test1">ajax call</g:remoteLink> 
    </p> 
    <p>Message = ${message}</p> 
    <p id="test1">Blank</p> 
</body> 
</html>

views/layouts/person.gsp (layout template for person controller)

<html> 
<head> 
    <title>Test App - <g:layoutTitle/></title> 
    <g:layoutHead/> 
</head> 
<body> 
    <h1>Test App</h1> 
    <g:layoutBody/> 
</body> 
</html>

I access person controller with the home view: http://localhost:8080/test/person/home

the page renders as: Test App ajax call (hyperlink) Message = Hello Blank

"Test App" is from the template. When I click "ajax call" it makes an asynchronous call to PersonController's ajaxTest method (verified with println). All ajaxTest does is println and render static text. This resultant in the following:

Test App 
ajax call 
Message = Hello 
Test App 
ajax message

Note that the template is being rendered within "test1" <p> which results in the second "Test App".

I'm running Grails 1.1.1. Any ideas? The code seems straightforward. I downloaded the Grails source and looked at RenderDynamicMethod.java. It doesn't do any template rendering unless template is in the argument list, which it isn't. So my only guess is something up steam is rendering the template again.

回答1:

Resolved: Adding contentType results in the template not being rendered:

render text: "Name: ${person.name}", contentType: "text/plain"

回答2:

Make your client side javascript code handle a JSON respond and render your response with:

render [text:"Name: ${person.name}"] as JSON

回答3:

You might be getting burnt by the 'layout-by-convention' feature in Grails. If your layout name matches the controller name prefix, for example, Grails will apply the layout to every view managed by that controller. Unfortunately, it even applies to text and templates. There are currently a few JIRAs logged regarding this (see http://jira.grails.org/browse/GRAILS-7624 for example). I got burnt by this today. I resolved it by simply renaming my layout gsp such that it doesn't match any controller name. My layout was initially named 'storefront.gsp' and I have a controller named StorefrontController. I renamed the layout to 'public.gsp'.

回答4:

We've found that explicitly returning false from the action fixes this.

I believe doing render foo as JSON returns false implicitly.

来源：https://stackoverflow.com/questions/1464933/grails-render-renders-the-template

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grails

gsp