Complex forms with Django - django

Question

Consider the following survey question:
Do you like this question? (choose one)
Yes
No, because
I don't like its formatting
I don't like the wording
Other reason: ...................
Other response (please specify) ......................
I'm trying to represent a series of questions, some of which are like that. Some are more simple (just a list of choices). But I'm having some problems trying to square this off with Django and its own way of doing forms. We have the following problems:
We need server side validation. Only one choice can be specified. And in the case of the "other" choices above, those need a follow-up charfield.
We need to squeeze a charfield into the options! I'm fairly sure I can hack these in via the templates but keep that in mind.
Just to complicate things, the questions and their answers need to be editable. I've done this with YAML already and to the point of generating the form, that works fine.
So what's the best way to hack the Django form system to allow me to do this? Should I bother with django.forms at all or just write something that does everything in its own way? How would you do this?

Answer 1

If you want to avoid dealing with forms I suggest using jquery's $.ajax() method. Basically, you simply need to create a blank form model to catch the POST, then you can grab the data and do with it what you want. Here is an example:
#models.py
class BlankForm(forms.Form):
def __unicode__(self):
return "BlankForm"
#views.py
def my_view(request):
if request.method == 'POST':
if 'answer' in request.POST:
form = BlankForm(request.POST)
if form.is_valid():
foo = request.POST.__getitem__('add')
bar = request.POST.__getitem__('bar')
baz = request.POST.__getitem__('baz')
#Do stuff with your data:
return HttpResponse('ok')
Then in your webpage you could some something like this:
<script type="text/javascript">
function getCookie(name) {
var cookieValue = null;
if (document.cookie && document.cookie != '') {
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
var cookie = jQuery.trim(cookies[i]);
// Does this cookie string begin with the name we want?
if (cookie.substring(0, name.length + 1) == (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
function csrfSafeMethod(method) {
// these HTTP methods do not require CSRF protection
return (/^(GET|HEAD|OPTIONS|TRACE)$/.test(method));
}
var csrftoken = getCookie('csrftoken');
$.ajaxSetup({
crossDomain: false, // obviates need for sameOrigin test
beforeSend: function(xhr, settings) {
if (!csrfSafeMethod(settings.type)) {
xhr.setRequestHeader("X-CSRFToken", csrftoken);
}
}
});
$.ajax({
type: 'POST',
data: {
'answer': true,
'foo': foo,
'bar': bar,
'baz': baz
},
dataType: 'application/json'
});
}
</script>
All the stuff about the cookies and CSRF token have to do with django's CSRF protection system. Basically all you would need to worry about would be editing the Data field in the $.ajax() method

Answer 2

The various options would be a ForeignKey to another table containing the responses. You'd have to have multiple fields in that FK to hold both the main answer and the subanswer, and you'd have to regroup (or reorder, if you need an explicit order) apropriately. You'd also need a CharField in order to hold the "other" response. It might be easiest to encapsulate both fields in a custom field, and use a custom widget to display the controls in the form.