Create a dynamic JSON with play - json

Question

i'm writing a Play 2.3.2 application using Reactivemongo driver (with Scala).
I've the recommendation.user collection that store all the user data.
One document has the following form:
{
"_id" : ObjectId("542e67e07f724fc2af28ba75"),
"id" : "",
"email" : "luigi#gmail.com",
"tags" : [
{
"tag" : "Paper Goods:Liners - Baking Cups",
"weight" : 2,
"lastInsert" : 1412327492874
},
{
"tag" : "Vegetable:Carrots - Jumbo",
"weight" : 4,
"lastInsert" : 1412597883569
},
{
"tag" : "Paper Goods:Lialberto- Baking Cups",
"weight" : 1,
"lastInsert" : 1412327548205
},
{
"tag" : "Fish:Swordfish Loin Portions",
"weight" : 3,
"lastInsert" : 1412597939124
},
{
"tag" : "Vegetable:Carrots - alberto#gmail.com",
"weight" : 2,
"lastInsert" : 1412597939124
}
]
}
Now i'm writing a method that returns all the tags of a particular user.
I return a JSOn responce.
In play how can i create a dynamic json??
My return json has the following form:
{
"tags": [
{"tag": "tag1"},
{"tag": "tag2"}
]
}
This is my method implementation:
def userTag(user: String) = Action.async {
//obtain all the users saved in the db.
val allUser : Future[Option[User]] = Users.find(Json.obj("email" -> user)).one
val futureComputation = allUser map {
(user: Option[User]) =>
user match {
case Some(x) => x.tags match {
case Some(userTags) => val tags: List[Tag] = userTags.map{tag: (Tag, Double, Long) => tag._1} //obtain all the Tag objects
//here for every element in the tags variable i want to add it add the json.
case None => Ok(Json.obj()) //return an empty json.
}
case None => Ok(Json.obj()) //return an empty json
}
}
futureComputation
}
How can i solve my problem??

Answer 1

Solved using:
def userTag(user: String) = Action.async {
//obtain all the users saved in the db.
val allUser : Future[Option[User]] = Users.find(Json.obj("email" -> user)).one
val futureComputation = allUser map {
(user: Option[User]) =>
user match {
case Some(x) => x.tags match {
case Some(userTags) => val tags = userTags.map{tag: (Tag, Double, Long) => val t = tag._1; t.category + ":" + t.attr} //obtain all the Tag objects
val arrayTags = for(tag <- tags) yield{Json.obj("tag" -> tag)} //crete the array json
Ok(Json.obj("tags" -> arrayTags)) //return the json corresponding to the user.
case None => Ok(Json.obj()) //return an empty json.
}
case None => Ok(Json.obj()) //return an empty json
}
}
//return the Future computation JSON responce.
futureComputation
}