[Zope-dev] z3c.form - creating a file upload widget

[Stephan Richter]

On Thursday 12 March 2009, Martin Aspeli wrote:
> I'm writing a custom file widget for z3c.form that works like the
> Archetypes file widget that Plone uses and the formlib widget in
> collective.namedfile. That is, after you've uploaded a file once, you're
> given a radio button to decide whether to upload a new file, or leave
> the existing file in place.
>
> I can't quite figure out how to do this, though. I've tried to override
> the extract() method on the widget to look in the request for the
> special marker that says "user chose not to change the file". However, I
> don't know what to return. If I return NOVALUE, then validation fails
> (if the field is required). If I try to look up the field value from the
> data manager and return it, it ends up setting the field back on itself,
> which is wasteful.

All great questions and I am not sure I have good answers. I think you want 
a "NONEWVALUE" or so marker and have the validator honor it correctly.

If you make a proposal to enrich the API, I'll probably agree to it. :-)

Regards,
Stephan
-- 
Stephan Richter
Web Software Design, Development and Training
Google me. "Zope Stephan Richter"