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Python Django Forms Forms Create a Validator

Posted by Gerald Wells
Gerald Wells
12,763 Points

ValidationError problem

I want to make sure that the email address isn't from any of my coworkers at Treehouse. We'll solve this with a custom validator.

Add a new function named not_treehouse that takes a single argument. If the argument ends with "@teamtreehouse.com", raise aValidationError`. You can use whatever error message you want.

Remember, too, that it's a good idea to standardize your input before testing it, so you might want to lower- or uppercase the value.

def not_treehouse(value):
  value = value.lower()
  if '@teamtreehouse' in value:
    raise ValidationError('email is not valid')


class LeadShareForm(forms.Form):
    email = forms.EmailField(validators=[not_treehouse])
    link = forms.URLField()
    honeypot = forms.CharField(widget=forms.HiddenInput, required=False)

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,457 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,457 Points

Close but a few corrections needed:

  • check that string is at end of value
  • check '@teamtreehouse.com'
  • use correct path to ValidationError
def not_treehouse(value):
  value = value.lower()
  # check for endswith
  if value.endswith('@teamtreehouse.com'):
    raise forms.ValidationError('email is not valid')
Gerald Wells
Gerald Wells
12,763 Points

Thank you!

V K
V K
5,237 Points
V K
V K
5,237 Points

A quick note to people who might be stumped like I was. The custom validator/function must be outside of the class.
So it should look like this

from django import forms

def not_treehouse(value):
        value = value.lower()
        if value.endswith('@teamtreehouse.com'):
             raise forms.ValidationError('Email is not valid')

class LeadShareForm(forms.Form):
    email = forms.EmailField()
    link = forms.URLField()
    honeypot = forms.CharField(widget=forms.HiddenInput, required=False)


    def clean_honeypot(self):
        honey = self.cleaned_data['honeypot']
        if len(honey):
            raise forms.ValidationError('Bad robot!')
        return honey