Mapping and Validation

GitBucket uses scalatra-forms to validate request parameters and map them to the scala object. This is inspired by Play2 form mapping / validation.

At first, define the mapping as following:

import org.scalatra.forms._

case class RegisterForm(name: String, description: String)

val form = mapping(
  "name"        -> text(required, maxlength(40)),
  "description" -> text()
)(RegisterForm.apply)

The servlet have to mixed in gitbucket.core.controller.ValidationFormSupport to validate request parameters and take mapped object. It validates request parameters before action. If any errors are detected, it throws an exception.

class RegisterServlet extends ScalatraServlet with ValidationFormSupport {
  post("/register", form) { form: RegisterForm =>
    ...
  }
}

In the view template, you can add client-side validation by adding validate="true" to your form. Error messages are set to span#error-<fieldname>.

<form method="POST" action="/register" validate="true">
  Name: <input type="name" type="text">
  <span class="error" id="error-name"></span>
  <br/>
  Description: <input type="description" type="text">
  <span class="error" id="error-description"></span>
  <br/>
  <input type="submit" value="Register"/>
</form>

Client-side validation calls <form-action>/validate to validate form contents. It returns a validation result as JSON. In this case, form action is /register, so /register/validate is called before submitting a form. ValidationFormSupport adds this JSON API automatically.

For Ajax request, you have to use ajaxGet or ajaxPost to define action. It almost same as '''get''' or '''post'''. You can implement actions which handle Ajax request as same as normal actions. Small difference is they return validation errors as JSON.

ajaxPost("/register", form){ form =>
  ...
}

You can call these actions using jQuery as below:

$('#register').click(function(e){
  $.ajax($(this).attr('action'), {
    type: 'POST',
    data: {
      name: $('#name').val(),
      mail: $('#mail').val()
    }
  })
  .done(function(data){
    $('#result').text('Registered!');
  })
  .fail(function(data, status){
    displayErrors($.parseJSON(data.responseText));
  });
});