How to process Django validation errors

Question

I'm having some trouble grokking Django forms and validation.

#views.py:
def create(request):
    if request.method == 'POST':
        form = CreateDocumentForm(request.POST)
        if form.is_valid():
            doc = Document.objects.create(name=form.cleaned_data['name'])
    #snip


#forms.py:
    class CreateDocumentForm(forms.ModelForm):
    name = forms.CharField()
    def clean_name(self):
        cleaned_name = self.cleaned_data['name']
        rgx = re.compile('^(\w|-|\.)+$')
        if rgx.match(cleaned_name) == None:
            raise ValidationError("invalidchars")
        return cleaned_name

The logic is working properly, but I don't know how to tell which kind of VaidationError was raised. Also - This is handled by an Ajax request, so I won't be using templating in the repsonse. I need to get the status of what failed in this view.

thx

Ian Clelland · Accepted Answer · 2012-10-20 20:22:23Z

4

You generally won't see the ValidationErrors themselves. If you call form.is_valid, then the errors that occur during validation are all collected and returned to you as a dictionary, form.errors

You can check that dictionary for errors relating to any specific field. The result for any field with errors should be the string value of any ValidationErrors that were raised for that field.

In your view, then, if form.is_valid() returns False, then you can do this:

if 'name' in form.errors:
    for err_message in form.errors['name']:
        # do something with the error string

edited Oct 20, 2012 at 20:22

answered Oct 20, 2012 at 20:15

Ian Clelland

44.4k8 gold badges90 silver badges88 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Daniel Roseman Over a year ago

And since this is an Ajax request. you can send the error dictionary (perhaps converted to JSON) back as the response.

Lester Burnham Over a year ago

ha. I actually just came back to report that I figured this out - however - forms.errors['name'] contains the string that was passed to the ValidatioError constructor wrapped in markup: <ul class="errorlist"><li>invalidchars</li></ul>. How can I get just the error? Also - am i doing this right, or is there a better (preferred) way?

Alasdair Over a year ago

The unicode method for form.errors['name'] gives the html markup, but if you loop through form.errors['name'] as Ian suggests, you'll get a list of the error strings. In your example, there is only one error string in the list, which you can see with f.errors['name'][0].

Collectives™ on Stack Overflow

How to process Django validation errors

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related