NullableIntegerField

[kmarekspartz]

I would like a field, which if left blank is None, and otherwise behaves like IntegerField.

As a workaround, we made this class:

class NullableIntegerField(IntegerField):
    """
    An IntegerField where the field can be null if the input data is an empty
    string.
    """

    def process_formdata(self, valuelist):
        if valuelist:
            if valuelist[0] == '':
                self.data = None
            else:
                try:
                    self.data = int(valuelist[0])
                except ValueError:
                    self.data = None
                    raise ValueError(self.gettext('Not a valid integer value'))

Is there a better way to do this? Should I make some tests and a pull request?

[lepture]

IntegerField with DataRequired validator.

[kmarekspartz]

That doesn't seem to do what I'm looking for, though the Optional validator may be. Let me try it out tomorrow.

[prencher]

It's not the most intuitive thing in the world, but Optional is indeed what you want here, and for any other coercing validator. They are essentially required by default.

We have some plans for 2.0 to address this once and for all, without the slightly kludgey approach of using Optional.

[kmarekspartz]

Thanks.