[Zope] external validators

[Ian McMeans]

Hello! I'm having some trouble with external validators. This may or may not
have something to do with my earlier troubles re. forms.

Previously, (before I knew that plone's join_form.pt was using formulator) I
was doing manual validation on the fields from join_form.pt.

I put code like this in plone_form_scripts\validate_registration:

if REQUEST.get('field_shackname', '').startswith('anon@'):
    errors['shackname'] = 'Sorry... no anons allowed.'

Not very pretty, but I didn't know any better. I started getting some odd
errors that I am (still) unable to fix, and nobody had anything to say about
those errors on the zope list. So I started reading the source code until I
found formulator, which looked like a better alternative to manually
checking. So I added an external_validator attribute to my form fields in my
join_form, then wrote the external_validator as an external script.

However, my join_form page never seems to fail from the external validator.
I changed the external validator to write a small file to my hard drive, so
that I could detect whether or not the function had been called. And the
weird thing is that the function isn't being called.

Here is the function:

def validate_shackname(REQUEST):
    open(r'f:\new.txt', 'w').write('foo foo')
    return "ERROR"

Here is how I (try) to use it in my join_form.pt:

<input type="text" name="field_shackname" size="25"
                       value="shackname"
                       tal:attributes="value shackname"
                       external_validator="validate_shackname">

validate_shackname is the name of the external script, as well as the name
of one of it's functions. Is it correct that the function takes REQUEST as a
parameter? Is there something I'm doing wrong?

and I've still got the error from earlier, where the form doesn't complain
when a field is invalid. I don't know if that's related...