Scala Object From JSON Request - json

Question

I have a controller method in my Scala Play project that takes JSON as input. I would like to turn this JSON into a model object I have.
Here is my controller method:
def broadcastPost = Action(parse.json) { request =>
(request.body).asOpt[Post].map { post =>
Post.create(post.channelId, post.message, post.datePosted, post.author)
Ok(play.api.libs.json.Json.toJson(
Map("status" -> "OK", "message" -> ("Post created"))
))
}.getOrElse {
BadRequest(play.api.libs.json.Json.toJson(
Map("status" -> "Error", "message" -> ("Missing parameter [Post]"))
))
}
}
And here is the model:
case class Post(id: Pk[Long], channelId: Long, message: String, datePosted: Date, author: String)
and its implicit formatter:
implicit val postFormat = (
(__ \ "id").formatNullable[Long] and
(__ \ "channelId").format[Long] and
(__ \ "message").format[String] and
(__ \ "datePosted").format[Date] and
(__ \ "author").format[String]
)((id, channelId, message, datePosted, author) => Post(id.map(Id(_)).getOrElse(NotAssigned), channelId, message, datePosted, author),
(p: Post) => (p.id.toOption, p.channelId, p.message, p.datePosted, p.author))
When I send a POST request to that method with the following data:
{"channelId":1, "message":"Wanna get a game in?", "dateCreated":"5-15-2013", "author":"Eliot Fowler"}
I get the following response:
{"status":"Error","message":"Missing parameter [Post]"}
I am very new to Scala, so I may be overlooking something very simple here.

Answer 1

Instead of using asOpt, which loses the error, you should use validate, which will allow you to return the error message, and then see what the problem is, eg:
def broadcastPost = Action(parse.json) { request =>
request.body.validate[Post].fold({ errors =>
BadRequest(Json.obj(
"status" -> "Error",
"message" -> "Bad JSON",
"details" -> JsError.toFlatJson(errors)
))
}, { post =>
Post.create(post.channelId, post.message, post.datePosted, post.author)
Ok(Json.obj("status" -> "OK", "message" -> "Post created"))
})
}
Now, what I'm guessing that will tell you is that "5-15-2013" is not a valid date. The default date format for JSON in Play is yyyy-MM-dd. You can specify a custom one by modifying your format to say:
...
(__ \ "datePosted").format[Date](Format(Reads.dateReads("MM-dd-yyyy"), Writes.dateWrites("MM-dd-yyyy"))) and
...
Another built in one Reads.IsoDateReads, this is more standard than the American only month day year format, another approach that avoids this issue altogether is use a Long as milliseconds since epoch.