Parse mongoDB Document JSON to scala case class [duplicate] - json

Question

I am using MongoDB scala driver. I have a problem with fetching record from MongoDB.
Following is my MongoDB initialization
private val client: MongoClient = MongoClient()
private val database: MongoDatabase = client.getDatabase(“rulemgntdb”)
val WorkOrdercollection: MongoCollection[Document] = database.getCollection("workOrder")
Find query :
MongoFactory.WorkOrdercollection.find().collect().subscribe(
(results: Seq[Document]) =>
println(s”Found: #${results}“)
)
Results printed like this :
Found: #List(Document((_id,BsonString{value=‘5af153f49547a205f9798129’}), (workOrderId,BsonString{value=‘9a9e1ce8-c576-4a15-a1ff-4af780b14b7f’}), (thingId,BsonString{value=‘Mumbai_Robot_3’}), (alertId,BsonString{value=‘Alert_1’}), (description,BsonString{value=‘Robot is not in good condition’}), (lastViewedDate,BsonDateTime{value=1525781377952}), (suggestedMaintenanceDate,BsonDateTime{value=1525781377952}), (startDate,BsonDateTime{value=1525781377952})))
I want to map this Document to my Case class.
Case class is like :
case class WorkOrder (
var id : String = (new ObjectId()).toString(),
var workOrderId: String,
var thingId : String,
var alertId : String,
var description : String,
val lastViewedDate : Date,
val suggestedMaintenanceDate : Date,
val startDate : Date
)
If I do following for getting JSON string from Document :
MongoFactory.WorkOrdercollection.find(query).subscribe(
(user: Document) => println(user.toJson()), // onNext
(error: Throwable) => println(s"Query failed: ${error.getMessage}"), // onError
() => println("Done") // onComplete
)
Then I will get Following JSON String:
{ “_id” : “5af153f49547a205f9798129", “workOrderId” : “9a9e1ce8-c576-4a15-a1ff-4af780b14b7f”, “thingId” : “Mumbai_Robot_3", “alertId” : “Alert_1", “description” : “Robot is not in good condition”, “lastViewedDate” : { “$date” : 1525781377952 }, “suggestedMaintenanceDate” : { “$date” : 1525781377952 }, “startDate” : { “$date” : 1525781377952 } }
I can Parse JSON string to case class but...Look at “startDate” : { “$date” : 1525781377952 } I am not able to Parse MongoDB Date to scala Date
How can I map Document to Case class?

Answer 1

You need to provide a custom codec for $date field. The following shows how it is done in play-json but the concept is similar in other JSON libraries:
object WorkOrder {
implicit val dateRead: Reads[Date] =
(__ \ "$date").read[Long].map(date => new Date(date))
implicit val dateWrite: Writes[Date] = new Writes[Date] {
def writes(date: Date): JsValue = Json.obj("$date" -> date.getTime)
}
implicit val codec = Json.format[WorkOrder]
}

Answer 2

You could use a JSON library.
In play-json
case class WorkOrder (
id: String,
workOrderId: String,
thingId: String,
alertId: String,
description: String,
lastViewedDate: Date,
suggestedMaintenanceDate: Date,
startDate: Date
)
object WorkOrder {
implicit lazy val fmt = Json.format[WorkOrder]
}
def documentToWorkOrder(doc: Document): WorkOrder = {
Json.parse(user.toJson().toString).validate[WorkOrder] match {
case JsSuccess(_, workOrderObj) => workOrderObj
case JsError(throwable) => throw throwable
}
}
//then in your code
MongoFactory.WorkOrdercollection.find(query).subscribe(
(user: Document) => documentToWorkOrder(user),
(error: Throwable) => println(s"Query failed: ${error.getMessage}"),
() => println("Done")
)