Sending JSON to javascript on GSP

问题:

I'm using Grails 2.3.7 and I have a controller action as follows:

def testData(){
    def result = [:]
    result['name'] = "Sales"
    result['type'] = "bar"
    result['data'] = [5, 20, 45, 10, 10, 20]
    [data: result as JSON]
}

In the testData.gsp I'd like to get the JSON object in javascript:

<script>
    $(document).ready(function(){
        var data = JSON.parse(${data});
    })
</script>

Then I got an exception:

Uncaught SyntaxError: Unexpected token {

on the line:

var data = JSON.parse({"name":"Sales","type":"bar","data":[5,20,45,10,10,20]});

It looks like JSON is messed up. I think it used to work this way. Maybe it's new Grails? How can I fix this? Thanks.

Update: Problem solved. See the comments in the accepted answer.

Update2: When I check the app today, it failed again. I did what the docs required with the "raw" method but no luck. A workaround is to use the "Per Page Encoding". This one I tested thoroughly. It does work.

回答1:

The problem is that the JSON is being encoded as HTML. Try the following instead:

Controller

def testData() {
    def result = [:]
    result['name'] = "Sales"
    result['type'] = "bar"
    result['data'] = [5, 20, 45, 10, 10, 20]
    [data: result as JSON]
}

GSP

<script>
    var data = ${raw(data)};
</script>

You don't need $(document).ready because the JS code

var data = ${raw(data)};

is generated on the server-side

回答2:

Working solution :

def action() {
  [data: data as JSON]
}

GSP page:

<g:applyCodec encodeAs="none">
    var data = ${data};
</g:applyCodec>

回答3:

The encodeAsJSON() method works well for outputting JSON data into JavaScript:

Controller

def testData() {
   def data = [name: "Sales", values: [5, 20, 45]]
   [data: data]
   }

View (GSP)

<script>
var data1 = ${raw(data)};  //{name=Sales, values=[5, 20, 45]}
var data2 = ${raw(data as grails.converters.JSON)};  //{&quot;name&quot;:&quot;Sales...
var data3 = ${data.encodeAsJSON()};  //{"name":"Sales","values":[5,20,45]}  CORRECT!
</script>

Using raw() on a Groovy object does not produce JavaScript compatible output (see data1), and using it after the JSON converter results in unwanted " encoding (see data2). Using encodeAsJSON() produces the correct output (see data3).

Documentation:
http://grails.org/doc/latest/guide/security.html#codecs

Update:
I've switched to using a taglib with:

out << "<script>var data = " + raw((data as JSON) as String) + ";</script>"

回答4:

Not all grails versions support raw() method or g:applyCodec taglib.

The solution is to use <%= %> block to avoid escaping

 <%= users.collect({id:it.id,value:it.name}) as grails.converters.JSON%>

OR

<%= someJsString.encodeAsJavascript() %>

But best practice is to avoid using serverside generated JSON into GSP and refactor into getting the same JSON received via ajax request

回答5:

The following worked for me using Grails 2.4.3:

Controller:

def result = [:]
result['type'] = "bar"
result['data'] = [5, 20, 45]

model: [data: result as JSON]

GSP:

<script>
// this worked!
var data = ${raw(data as String)};
</script>

Produced desired result:

<script>
// this worked!
var data = {"type":"bar","data":[5,20,45]};
</script>

The accepted answer by Dónal DID NOT work for me:

Controller (same as my working example above)

GSP (did NOT work):

<script>
// did NOT work!!
var data = ${raw(data)};
</script>

Produced same bad result:

<script>
// did NOT work!!
var data = {&quot;type&quot;:&quot;bar&quot;,&quot;data&quot;:[5,20,45]};
</script>

回答6:

This worked for me in grails 3.1.9.

Controller:

def result = [:]
result['type'] = "bar"
result['data'] = [5,20,45]
result['key'] = token

[data:result as JSON]

GSP:

<script>

var data = '${raw(data as String)}';
var json = JSON.parse(data);
alert(json.type);

var authorization = json.key;

</script>

回答7:

In testData.gsp add

<%@page expressionCodec="none" %>

and in script

<script>
   $(document).ready(function(){
    var data = ${data};
})
</script>

回答8:

This might also help, passing data as simple model and parsing it as JSON in gsp.

def testData() {
    def result = [:]
    ...
    [data: result]
}

On View

<%! import grails.converters.JSON %>
...
<script>
function parseModelToJS(jsonString)
{
 jsonString=jsonString.replace(/\"/g,'"');
 var jsonObject=$.parseJSON(jsonString);
 return jsonObject
}

$(document).ready(function(){
 var data=parseModelToJS('${data as JSON}');
 console.log(data);
});
</script>

http://www.oodlestechnologies.com/blogs/Parse-model-to-json-on-gsp-in-grails

回答9:

You can do this,

import groovy.json.*
Map testMap = ['name': 'Test']
String jsonData = new JsonBuilder(testMap).toPrettyString()
render(view: view, model: ["data": jsonData], params: [:])

In your gsp:

 <script>
    var data = ${raw(data)};
</script>

Simple..