[mod_python] R: servlet form against publisher

Manera, Villiam writes:
> 
> Date: 03 Sep 2004 11:18:18 -0400
> From: Daniel Popowich <dpopowich at comcast.net>
> Subject: Re: [mod_python] servlet form against publisher
> To: mod_python user mailing list <mod_python at modpython.org>
> Message-ID: <m23c1zbcud.fsf at fenway.local.>
> 
> 
> Manera, Villiam writes:
> 
> >> ........
> >> Difference in retrieve fields from Form between publisher and servlet:
> >> 
> >> In publischer : req.form = util.FieldStorage(req, keep_blank_values=1)
> >> 
> >> In servlet : self.form = util.FieldStorage(self.req)        
> >> 
> >> So in servlet the fields not filled are not inserted in  self.form.list
> >> 
> >> Why this choice??
> 
> >Two reasons:
> 
> >1) Assuming you're going to retrieve the field like this:
> >
> >     field = self.form.getfirst('fieldname', somedefault)
> >
> >   then returning blank values is meaningless: regardless of whether
> >   or not the field was blank you'll get your default.
> 
> >2) With the mechanics of query_vars and form_vars in mpservlets, re
> >   automatic retrieval of fields and setting them as instance
> >   variables and setting defaults for missing fields, there is no
> >   need to keep blank values.
> 
> >Daniel Popowich
> 
> ===================================== remark ==================================
> 
> Ok, I suppose this reason, and I agree.
> But for me will be useful to have a variable in order to choose keep_blank_values=1 when I need it.
> 
> And I need it for most of the routine already written that I'm modifying in order to work fine if they are called from publisher or from servlet.

I still don't quite understand why you would need it.  Let's say a
request comes in like this:

   http://myserver/myservlet?foo=

In the current system, if I set query_vars like this:

   query_vars = ['foo']

then you get exactly what you need: empty values are stripped by
FieldStorage, but Servlet, not seeing the key, will set the instance
variable foo to its default, an empty string.

Daniel Popowich
-----------------------------------------------
http://home.comcast.net/~d.popowich/mpservlets/