Jam.py documentation

How to prohibit changing record

Let’s assume that we have an item with a boolean field “posted”, and if the value of the field is true, we must prohibit changing or deleting the record.

We can do this by writing the on_after_scroll event handler and using permissions property:

function on_after_scroll(item) {
    if (item.rec_count) {
        item.permissions.can_edit = !item.posted.value;
        item.permissions.can_delete = !item.posted.value;
        if (item.view_form) {
            item.view_form.find("#delete-btn").prop("disabled", item.posted.value);
        }
    }
}

In this event handler we check the value of the “posted” field and set the permissions property attributes to true.

We can also write the on_apply event handler in the server module of the item:

def on_apply(item, delta, params, connection):
  for d in delta:
      if d.posted.old_value:
          raise Exception('Document posted. No change allowed')