On Feb 11, 5:03 pm, harryos <oswald.ha...@gmail.com> wrote:
> 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
In answer to your first question, form.instance is showing the old
values because you haven't called form.save() yet. The instance isn't
updated until you do.
For the second question, all this logic belongs in the form's clean()
method. If you do it there, your validation errors will be included in
the form itself and you won't have to worry about all those if
statements.
--
DR.
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