Handling JSON requests in Play Framework 2.0 Scala

Question

I am trying to send data from the client to the server using a JSON request. The body of the JSON request looks like this: ``` { "upload": { "ok":"some message", "assemblyId":"a9d8f72q3hrq982hf98q3" } } ``` Play is able to recognize the request body as JSON but when I try to parse individual values, namely the "upload" object, Play complains that it can't find the specified parameter. The Scala method is as follows: ``` def add(course:Long) = withAccount { account => implicit request => println() println(request.body) // output: AnyContentAsJson({"upload":{"ok":"ASSEMBLY_COMP... request.body.asJson.map { json => println() println(json) // output: {"upload":{"ok":"ASSEMBLY_COMPLETED","assemb... (json \ "upload").asOpt[models.SomeClass].map { upload => Ok("Got upload") }.getOrElse { BadRequest("Missing parameter [upload]") } }.getOrElse { BadRequest("Expecting Json data") } } ``` I'm having trouble understanding why the above code fails. The method has no trouble mapping the request bod…

Accepted Answer

To do asOpt[models.SomeClass] there needs to be a `Reads` instance for it to work.

Here is an example

```
case class SomeClass(ok: String, assemblyId: String)
implicit object SomeClassReads extends Reads[SomeClass] {
  def reads(json: JsValue) = 
    SomeClass((json \ "ok").as[String], (json \ "assemblyId").as[String])
}
```

You can see how you would implement a Reads instance at https://github.com/playframework/Play20/blob/2.0.x/framework/src/play/src/main/scala/play/api/libs/json/Reads.scala#L35

Handling JSON requests in Play Framework 2.0 Scala

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