How to exclude property of a collection in JSON rendering in Grails 2.3 - rest

Question

I am trying to setup a rest webservice (JSON) this is what I am getting:
{"name":"test","routines":[{"class":"Routine","id":1},{"class":"Routine","id":2}]}
This is what I want to get:
{"name":"test","routines":[{"name": "routine-1"},{"name": "routine-2"}]}
I have these domains:
class Program {
String name;
static hasMany = [routines: Routine]
}
class Routine {
String name
}
I have this controller:
class ProgramController extends RestfulController {
static responseFormats = ['json']
def show(Program program) {
respond program
}
}
I added this in the resources.groovy
programRenderer(JsonRenderer, Program) {
excludes = ['class', 'id']
}
routineRenderer(JsonRenderer, Routine) {
excludes = ['class', 'id']
}
How do I include the name property of Routine in the json response using the show method/action of ProgramController?

Answer 1

The ObjectMarshaller approach is the technically correct way. However, the code is cumbersome to write and it's a maintenance headache syncing the fields of the domain with the marshaller.
In the spirit of being Groovy and keeping things really simple, we've been quite happy just adding a little out() method to each REST domain.
Program.groovy
class Program {
String name
static hasMany = [routines: Routine]
def out() {
return [
name: name,
count: routines?.size(),
routines: routines?.collect { [name: it.name] }
]
}
}
ProgramController.groovy
import grails.converters.JSON
class ProgramController {
def show() {
def resource = Program.read(params.id)
render resource.out() as JSON
}
}
JSON Response
{
name: "test",
count: 2,
routines: [{ name: "routine-1" }, { name: "routine-2" }]
}
The out() method approach makes it easy to customize the response JSON, such as adding count for the number of routines.