Which is the best way to validate errors in Django?

Question

I found that there is a lot of ways to validate errors in Django, I’m just wondering which one is preferable and why?

e.g.

using clean in form, like:

    deadline = self.cleaned_data.get('deadline')
    if datetime.strptime(str(deadline)[:19], '%Y-%m-%d %H:%M:%S') < datetime.today():
        raise forms.ValidationError(_('Deadline cannot be in past!'))
    return deadline

before saving we can validate if there is any error and sending the instance if everything right, like:

 def save(self, force_insert=False, force_update=False, *args, **kwargs):
     if datetime.strptime(str(deadline)[:19], '%Y-%m-%d %H:%M:%S') < datetime.today():
         raise forms.ValidationError(_('Deadline cannot be in past!'))
     else:
         super(MODEL, self).save(force_insert, force_update, *args, **kwargs)

and not forgetting the validators in the model where I can use one in the filed it self like:

 deadline = models.DateTimeField(
               verbose_name=_('deadline'),
               validators=[MaxValueValidator(datetime.datetime.today())],
               help_text=_('Note that the end time will be at the midnight of the day you picked.'),
)

Also, we can do that in the forms in the class form we can check before saving if everything is right.

I want to know which is the best as a programmer and write a professional code.

Asked By: atf98

||

Source

Answer 1

the best way to validate model is using
clean_fields the reason is when an error occurs in the clean_fields it shows only for that particular field and this error is for validation one field

class ContactForm(forms.Form):
    message = forms.CharField(widget=forms.Textarea)

    def clean_message(self):
        message = self.cleaned_data['message']
        message = message.replace('a', '') # remove all "a"s from message
        if len(message) >= 5:
            raise ValidationError('Too many characters ...')
        return message

Answered By: Kishan Parmar

Answer 2

In MVC, anything that touches the database should be in the model layer. You could have a method like ‘is_valid_email(…)’ on the User model and call that from your Form.

Note that the Model layer doesn’t mean that you have to have a Class per table in your database VS creating new classes.

The Form is the Controller in DRF, I would go with option 1.

Answered By: NeX'T'iME

Which is the best way to validate errors in Django?

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