ValidationError in Django

Question

Hi I am very new at Django. I am working on a small project in which i am using modelform. For date field i want to do custom validation i.e. whenever a user enter a date before today's date it should display a error message near date field. I have written code as per the django's documentation, but it gives ValidationErrors for the raise statement in modelform. like ValidationError at /add_task/ [u"Please enter valid date. Either today's date or after that."]

Please help me how to overcome this problem. Thanks in advance.

Codes of my models:

from django.db import models

class MyTask(models.Model):

    summary=models.CharField(max_length=100)

    description=models.CharField(max_length=500)

    due_date=models.DateField(null=True)

    completed_status=models.BooleanField()

    def __unicode__(self):
        return self.summary

Codes of my modelform:

from django.forms import ModelForm, Textarea

from django.forms.extras.widgets import SelectDateWidget

from django.core.exceptions import ValidationError

from assignment.models import MyTask

import datetime

class AddTaskForm(ModelForm):

    class Meta:

        model=MyTask

        fields=('summary','description','due_date')

        widgets = {
            'description': Textarea(attrs={'cols': 50, 'rows': 10}),
            'due_date':SelectDateWidget(),
        }

    def get_due_date(self):

        diff=self.cleaned_data['due_date']-datetime.date.today()

        if diff.days<0:

            raise ValidationError("Please enter valid date. Either today's date or after that.")

    else:

            return self.cleaned_data['due_date']    

    def get_summary(self):

            return self.cleaned_data['summary']

    def get_description(self):

            return self.cleaned_data['description']

Answer 1

Your validation method needs to be called clean_due_date. In Django < 3 it should raise forms.ValidationError, but in Django 3 it should use core.exceptions.ValidationError.

I have no idea what the get_summary and get_description methods are for, they aren't called and don't do anything useful.

See the Django 3 docs here and the Django 2 docs here.