I am learning Play! and I have followed the To do List tutorial. Now, I would like to use Squeryl in place of Anorm, so I tried to translate the tutorial, and actually it works.
Still, there is one little thing that irks me. Here is the relevant part of my model
def all: Iterable[Task] = from(tasks) {s => select(s)}
and the corresponding action in the controller to list all tasks
def tasks = Action {
inTransaction {
Ok(views.html.index(Task.all, taskForm))
}
}
The view contains, for instance
<h1>@tasks.size task(s)</h1>
What I do not like is that, unlike in the methods to update or delete tasks, I had to manage the transaction inside the controller action.
If I move inTransaction to the all method, I get an exception,
[RuntimeException: No session is bound to current thread, a session must be created via Session.create and bound to the thread via 'work' or 'bindToCurrentThread' Usually this error occurs when a statement is executed outside of a transaction/inTrasaction block]
because the view tries to obtain the size of tasks, but the transaction is already closed at that point.
Is there a way to use Squeryl transaction only in the model and not expose these details up to the controller level?
Well. It's because of lazy evaluations on Iterable that require session bound (size() method). This might work if you turn Iterable into List or Vector (IndexedSeq) I suppose.
from(tasks)(s => select(s)).toIndexedSeq //or .toList