How to create AJAX edit form in scala lift for one to many relationship?

Question

I'm trying to create form to edit one to many relationship. I've created two classes:

class StudentGroup extends LongKeyedMapper[StudentGroup] with IdPK with OneToMany[Long, StudentGroup] {
  object groupName extends MappedString(this, 20)
  object students extends MappedOneToMany(Student,Student.studentGroup)
}


class Student extends LongKeyedMapper[Student] with IdPK {
  object firstName extends MappedString(this,35)
  object lastName extends MappedString(this,35)
  object studentGroup extends MappedLongForeignKey(this, StudentGroup)
}

Then I created a snippet to display a group with following code:

  val addStudentContent: NodeSeq = <div>
    <input type="text" placeholder="First Name"></input>
    <input type="text" placeholder="Last Name"></input>
  </div>

  def addStudent = AppendHtml("studentlist", addStudentContent)

  def render =
      "#addstudent" #> SHtml.ajaxButton("Add student", () => addStudent)

Now after clicking 'Add student' button two new fields appeared and I can put first and last name there. Problem is - how to store those data in database? Any hint?

Thanks

Answer 1

There are several ways you can begin to solve this problem. I never use Mapper myself, so there may be a much better way than what I am suggesting. However, something like the Ajax example in Simply Lift should get you started. Applying it to your code, we would get something like the following.

object StudentSnippets {
  val addStudentContent: NodeSeq = <form data-lift="form.ajax">
      <div data-lift="StudentSnippets.ajaxSubmit"> // Calls ajaxSubmit below
        <input name="first" type="text" placeholder="First Name"></input>
        <input name="last"  type="text" placeholder="Last Name"></input>
        <input type="submit" value="Submit"></input>
      </div>
    </form>

  def addStudent = AppendHtml("studentlist", addStudentContent)

  def render =
    "#addstudent" #> SHtml.ajaxButton("Add student", () => addStudent)

  private object first extends RequestVar("")
  private object last  extends RequestVar("")

  def ajaxSumbit = {
    "name=first" #> SHtml.text(first.is, first(_), "id" -> "the_name") &
    "name=last"  #> (SHtml.text(last.is, last(_)) ++ 
      SHtml.hidden(ajaxProcess)) // Calls ajaxProcess below
  }

  def ajaxProcess = {
    println("First is "+first.is)
    println("Last is "+last.is)
    Noop  // This is the JS that will run after submit.
  }
}

You can view another approach here on the wiki.

For more help with Lift, I strongly recommend posting your questions to the Lift Google Group. You will find that you get swarmed with Lift help more so than other forums such as SO.