wtforms Form class subclassing and field ordering

Question

I have a UserForm class:

class UserForm(Form):
    first_name = TextField(u\'First name\', [validators.Required()])
    last_name = TextField(u\'Last name\', [va         


        

Answer 1

I solved this by defining an additional __order attribute on my Form class, and overriding the __iter__ method so that the returned iterator's data is sorted first according to the definition. It might not be quite efficient, but there are not that many fields on a form, that it could cause any problem. It also works with fields from subclassed forms.

class MyForm(Form):
    field3 = TextField()
    field1 = TextField()
    field2 = TextField()

    __order = ('field1', 'field2', 'field3')

    def __iter__(self):
        fields = list(super(MyForm, self).__iter__())
        get_field = lambda field_id: next((fld for fld in fields
                                           if fld.id == field_id))
        return (get_field(field_id) for field_id in self.__order)