error check for start ,end datetime values in view

[harryos]

hi
I have an entry model and its modelform .The entry model has a
start,end datetimes.I want to prevent the user from mistakenly
entering an end datetime value which is before the start datetime.(ie,
end=11feb2010 and start=12feb2010 is wrong).I tried to do the error
check in an add_entry() view.
I gave some print statements to find out values at each stage.

I have given in my entry model definition default values for start,end
datetimes as now (ie default=datetime.datetime.now) .Even if I give
start time :2009-10-11 09:03:22
end time   :2009-10-11 08:03:22(end_time is before start_time -
intentionally)
the print statements show that form.instance.start_time and
form.instance.end_time are taken from the default values where
end_time is >start_time
This causes datecheck to return True and thus my error check doesn't
work.
However,the cleaned data shows the values which I entered while
creating the entry.

I can't understand why the form.instance is showing default values for
the datetime fields whereas cleaned_data has the user input values.Can
anyone tell me?


def add_entry(request):
        print 'in add_entry()'
        errors={}
        if request.method=='POST':
                form=MyEntryForm(request.POST)
                print 'add_entry():got  POST data'
                print 'form.instance.start_time=',form.instance.start_time
                print 'form.instance.end_time=',form.instance.end_time
                if form.is_valid() and
date_check(form.instance.start_time,form.instance.end_time):
                        cd=form.cleaned_data
                        print 'add_entry():cleaned data;',cd
                        print 'saving entry'
                        form.save()
                        return redirect('entry_archive_index')
                else:
                        print 'add_entry():POST:invalid form'
                        errors.update(form.errors)
                        form=MyEntryForm()
        form=MyEntryForm()
        print 'add_entry()GET'
        return render_to_response('myapp/add_entry.html',
{'entryform':form,'errors':errors})


def date_check(start,end):
        if start < end:
                return True
        else:
                return False


Here is the output of print statements
============
[11/Feb/2010 09:03:45] "GET /myapp/entries/addentry/ HTTP/1.1" 200
2181
in add_entry()
add_entry():POST:form got from POST data
form.instance.start_time= 2010-02-11 09:04:32.093058
form.instance.end_time= 2010-02-11 09:04:32.093152
add_entry():cleaned data;
{ 'start_time': datetime.datetime(2009, 10, 11, 9, 3, 22),
  'end_time'  : datetime.datetime(2009, 10, 11, 8, 3, 22)}
saving entry
[11/Feb/2010 09:04:32] "POST /myapp/entries/addentry/ HTTP/1.1" 302 0


========


So I rewrote the error check based on cleaned_data
errors={}
if form.is_valid():
                        cd=form.cleaned_data
                        start_t=cd['start_time']
                        end_t=cd['end_time']
                        if not date_check(start_t,end_t):
                                date_error={'datetime_error':'starttime should 
be before
endtime !'}
                                errors.update(date_error)
                                return 
render_to_response('myapp/add_entry.html',
{'entryform':form,'errors':errors})
                        print 'saving entry'
                        form.save()
                        return redirect('entry_archive_index')
                else:
                        print 'add_entry():invalid form'
                        errors.update(form.errors)
                        form=MyEntryForm()
                        return render_to_response('myapp/add_entry.html',
{'entryform':form,'errors':errors})


This does the correct error checking ..Still I want to know if there
is a better way of doing the error check on start and end dates..The
above code looks like a jumble of if else statements..and I know that
is not the best way of doing things


thanks
harry

-- 
You received this message because you are subscribed to the Google Groups 
"Django users" group.
To post to this group, send email to django-us...@googlegroups.com.
To unsubscribe from this group, send email to 
django-users+unsubscr...@googlegroups.com.
For more options, visit this group at 
http://groups.google.com/group/django-users?hl=en.