Play Framework 2 template Form None.get - scala

Question

Im new to Play 2 and Scala, and im getting a strange Exception in my template:
Execution exception
-------------------
[NoSuchElementException: None.get]
In /home/nic/workspaces/scala-ide/scims/app/views/persons/detailTabs/personal.scala.html at line 4.
1. #(personId: Long, personDetailTabForm: Form[dto.PersonDetailTab])(implicit formOptions: dto.PersonFormOptions)
2. #implicitFieldConstructor = #{ helper.FieldConstructor(support.bs3HorizField.f) }
3.
4. #persons.detail("personal", personDetailTabForm.get.firstName) {
The personDetailTabForm is an empty form object defined as:
val personalDetailTabForm: Form[PersonDetailTab] = Form(
mapping(
"firstName" -> text.verifying(nonEmpty),
"middleName" -> text,
"lastName" -> text.verifying(nonEmpty),
"gender" -> text,
"dateOfBirth" -> jodaDate("yyyy-MM-dd"),
"ethnicity" -> text,
"maritalStatus" -> text,
"password" -> text
)(PersonDetailTab.apply)(PersonDetailTab.unapply)
)
Any ideas as to what's wrong here?
I was under the impression a variable would have to be an Option to get a None?
Cheers
NFV

Answer 1

You are calling get on personDetailTabForm - Looking up it's ScalaDoc: http://www.playframework.com/documentation/2.2.x/api/scala/index.html#play.api.data.Form - it seems that .get returns the PersonDetailTab value that the form holds - IF, as the docs say, 'the submission was a success'.
You're seeing the None.get exception because most likely play.api.data.Form[T] simply uses Option[T] and get returns Some[T] when the form holds a valid value and None otherwise.
So on your line 4, in the scala template, you have something like
personDetailTabForm.get.firstName
That's a String, but you can expect a value only when the form's underlying PersonDetailTab itself has a value. I am not sure what you want to do, but you're dealing with a case where a value you want to render in a template might not be there, for whatever reason. In which case:
#personDetailTabForm.value.map{ personDetailTab =>
#persons.detail("personal", personDetailTab.firstName) // { ... whatever else
// anything else you want to render
} getOrElse { // errors in the form; personDetailTabForm cannot yield a valid personDetailTab
<h3> oops, what went wrong here? </h2>
}
It all depends on what you want to do in personal.scala.html. Form[T] is a good way
to deal with input and validation of some T thing, but if you are just displaying it,
and if you have a T (in your case PersonDetailTab) just pass that to the template as it is. If your PersonDetailTab may or may not exist, then just use Option[PersonDetailTab] instead Form[PersonDetailTab].