Grails GSON JSON views - json

Question

I want to generate JSON output similar to this one:
var json = {
id: "1",
name: "AAA",
children: [{
id: "2",
name: "BBB",
data: {
relation: "<b>Connections:</b><ul><li> AAA <div>(relation: direct)</div></li><li> CCC <div>(relation: direct)</div></li></ul>"
},
children: [{
id: "3",
name: "CCC",
data: {
relation: "<b>Connections:</b><ul><li> BBB <div>(relation: direct)</div></li></ul>"
},
children: []
}]
}, ....
Here is what I did so far:
grails create-domain-resource json.Object
class Object{
String name
String relation
static hasMany = [children: Object]
public String getData() {
def writer = new StringWriter()
_object.gson
//json g.render(hero)
json {
//data hero.data
data: {relation hero.relation}
name hero.name
}
Problem
I'm not able to produce:
data: {
relation: "<b>Connections:</b><ul><li> BBB <div>(relation: direct)</div></li></ul>"
},
Questions:
1) I've read the official documentation but I'm not able to find how to do transient fields
2) What is best approach of mixing json and xml / html.
3) How to pass json code to another view variable
thank you in advance

Answer 1

You can check the official documentation for gson views at:
http://views.grails.org/latest/#_json_view_api
Domain class
class Object{
String name
String relation
static hasMany = [children: Object]
public String getRelation() {
Template 1 object.gson
import json.Object
model {
Object object
}
json tmpl.object(object)
Template 2 _object.gson
import json.Object
model {
Object object
}
json {
id object.id
data(relation: object.relation)
name object.name
children g.render(object.children,[ excludes:['exclude_fields']])
//children g.render(object.children,[resolveTemplate: false]) // one to many relations - avoid circular error
//object2 object.book.name // one to one relations
}
ObjectController
import grails.plugin.json.view.JsonViewTemplateEngine
import org.springframework.beans.factory.annotation.Autowired
#Autowired
JsonViewTemplateEngine templateEngine
def test() {
def t = templateEngine.resolveTemplate('/object/object')
def writable = t.make(object: Object.get(params.id))
def sw = new StringWriter()
writable.writeTo( sw )
return [json:sw]
}
Questions:
1) I've read the official documentation but I'm not able to find how to do transient fields - you can use Named arguments which are valid values for objects or getters
2) What is best approach of mixing json and xml / html. - **I guess you can check : http://docs.groovy-lang.org/latest/html/gapi/groovy/json/StreamingJsonBuilder.html **
3) How to pass json code to another view variable - **check code above at objectController **