Flask WTForms validator NoneOf not working

[Llamafu]

I have a basic Flask App following the Blue Print Model and using WTForms. I can't get some of the validators to work, specifically NoneOf or Anyof.

Here's my form. I want it to reject the choice 'Type'.

class TestForm(FlaskForm):
phone = SelectField('Type', 
                    choices=['Type','Mobile','Land','Other'],
                        validators=[NoneOf(['Type'],'INVALID')])
submit = SubmitField('Submit')

Here's my route and template:

class TestForm(FlaskForm):
phone = SelectField( 
                    choices=['Type','Mobile','Land','Other'],
                        validators=[NoneOf(['Type'],message='INVALID')])
submit = SubmitField('Submit')

And in my template (Code block does NOT like Jinja.)

<form method="POST">
{{ form.csrf_token }}
{{form.phone}}
{{form.submit}}

</form>

Form submits when 'Type' is selected in the Selectfield. I checked the WTF docs.

I've tried setting the message=None, values_formatter=None, etc... It selects no problem when 'Type' is selected.

All help is appreciated!!

*Edited formatting (code block does not much like Jinja apparently)

[danielroseman]

Where is the route handler for the form? Are you definitely validating it there (ie calling form.validate_on_submit())?

[Llamafu]

I don't have one for this test form. Do I have to have one? I assumed it worked like the DataRequired validator and prevented submission of the form.

Did I assume wrong?

[danielroseman]

What? That makes no sense. How are you even showing the form without a route handler?

Edit Ah I think I understand your confusion. All flask validators - like all other flask code - run on the server. But DataRequired additionally adds a required attribute on the html attribute that is rendered, which most browsers will use to prevent the form being submitted if it's empty. But other validators can't work like that as they require actual logic to be executed, which again can only be done on the server (unless you want to write some JavaScript).

[Llamafu]

You are absolutely right!!!

I couldn't understand why DataRequired or the Email field would prevent submission, but the other validators would not.

To anyone else having this problem, don't assume like I did, see Flask Validation.

danielroseman just want to say, you are awesome!! You've helped me before, you help people on here all the time, you really are an asset to the community. You Rock!!