Scala Cookbook

15.14. POSTing JSON Data to a Play Framework Web Service

Problem

You want to create a web service using the Play Framework that lets users send JSON data to the service using the POST request method.

Solution

Follow the steps from the previous recipe to create a new Play project, controller, and model.

Whereas the previous recipe used the writes method of the Format object in the model, this recipe uses the reads method. When JSON data is received in a POST request, the reads method is used to convert from the JSON string that’s received to a Stock object. Here’s the code for the reads method:

def reads(json: JsValue): JsResult[Stock] = {
  val symbol = (json \ "symbol").as[String]
  val price = (json \ "price").as[Double]
  JsSuccess(Stock(symbol, price))
}

This method creates a Stock object from the JSON value it’s given. (The complete code for the model object is shown in the previous recipe.)

With this method added to the model, create a saveStock method in the Application controller:

import play.api._
import play.api.mvc._

object Application extends Controller {

  import play.api.libs.json.Json

  def saveStock = Action { request =>
    val json = request.body.asJson.get
    val stock = json.as[Stock]
    println(stock)
    Ok
  }

}

The saveStock method gets the JSON data sent to it from the request object, and then converts it with the json.as method. The println statement in the method is used for debugging purposes, and prints to the Play command line (the Play console).

Finally, add a route that binds a POST ...