How to POST an object with its childrens ? grails 3 RESTful - security - POST save new objects - json

Question

I am trying to do a simple POST to save a new object
class diagram
I want to POST a Question with the following attributes:
String name
static hasOne = [questionType: QuestionType]
Each Question has one abstract QuestionType extended by one of this objects:
Mcq (Multiple Choice Question)
SourceCode
Matching
...
For my Mcq, I have the following attributes:
static belongsTo = [questionType: QuestionType]
static hasMany = [propositions: Proposition]
static constraints = {
}
static mapping = {
propositions cascade: 'all-delete-orphan'
}
So my Mcq owns 0 to many Proposition
A Proposition is made of:
String body
Boolean isCorrect
String reason
I am using Postman to check my API. I don't have any UI for now.
My Question, Qcm and Proposition objects have a controller and a service to manage them.
My QuestionService:
class QuestionService {
def save(Question question) {
if (question == null) {
transactionStatus.setRollbackOnly()
render status: NOT_FOUND
return
}
if (question.hasErrors()) {
transactionStatus.setRollbackOnly()
respond question.errors, view:'create'
return
}
question.save flush:true
}
def update(Question question) {
if (question == null) {
transactionStatus.setRollbackOnly()
render status: NOT_FOUND
return
}
if (question.hasErrors()) {
transactionStatus.setRollbackOnly()
respond question.errors, view:'edit'
return
}
question.save flush:true
}
def delete(Question question) {
if (question == null) {
transactionStatus.setRollbackOnly()
render status: NOT_FOUND
return
}
question.delete flush: true
}
}
My QuestionController:
#Secured('ROLE_ADMIN')
#Transactional(readOnly = true)
class QuestionController {
//spring bean injected for the Controller to access the Service
def questionService
static responseFormats = ['json', 'xml']
static allowedMethods = [save: "POST", update: "PUT", delete: "DELETE"]
//views
def index(Integer max) {
params.max = Math.min(max ?: 10, 100)
respond Question.list(params), model:[questionCount: Question.count()]
}
def show(Question question) {
respond question
}
//actions
def save(Question question){
try { questionService.save question }
catch (e){ respond status: PRECONDITION_FAILED }
respond question, [status: CREATED, view:"show"]
}
def update(Question question) {
try { questionService.update question }
catch (e) { respond status: PRECONDITION_FAILED }
respond question, [status: OK, view:"show"]
}
def delete(Question question) {
try { questionService.delete question }
catch (e){ respond status: PRECONDITION_FAILED }
respond status: OK, view:"index"
}
}
I can get each Proposition, Mcq and Question with my index and show actions.
I don't allow my users to POST a new Proposition / Mcq. If they want to do it, they have to UPDATE the full Question itself. So only my Question can be modified (and modify others), others or in read-only.
My problem is that I can NOT POST this:
{
"name": "name1",
"questionType": {
"propositions": [
{
"body": "body proposition 1",
"isCorrect": true,
"reason": "reason proposition 1"
},
{
"body": "body proposition 2",
"isCorrect": false,
"reason": "reason proposition 2"
}
]
}
}
It always returns me a
[
null
]
But this works:
{
"name": "name1",
"questionType": {
"id": 1
}
}
So, in here, I can refer to a QuestionType already in my database (from my bootstrap) but I don't see how to create in cascade all of my Question, QuestionType, Qcm and Proposition.