Django: errors not being shown when form is submitted

Question

clean is not showing errors on my login form regardless of what my input is and regardless of what method of displaying errors I try in clean.

In my CustomUserCreationForm error displaying works perfectly. The only difference between the two is login extends forms.Form while Custom extends UserCreationForm

Also I'm using django-crispy-forms to render my forms

class LoginForm(forms.Form):
    username = forms.CharField(label=('UserName'),
            widget = forms.TextInput(attrs={'placeholder': _('Username')})
    )
    password = forms.CharField(label=('Password'),
            widget=forms.PasswordInput(attrs={'placeholder' : _('Password') }),
    )

    def helper(self):
            helper = FormHelper()

            helper.form_id = "Login"
            helper.form_method = "POST"
            helper.layout = Layout(Div(
                    Field('username', css_class='input-box-rounded'),
                    Field('password', css_class='input-box-rounded'),
                    Submit('Login', 'Login',  css_class='col-md-6 col-md-offset-3 rounded'),
                     css_class='col-md-4 col-md-offset-4 centered-div'))
            return helper

    def clean(self):

            cleaned_data = super(LoginForm, self).clean()

            if 'username' not in cleaned_data:
                    msg = _("Please enter a username")
                    self._errors['username'] = self.error_class([msg])
            if 'password' not in cleaned_data:
                    msg = _("Please enter a password")
                    raise forms.ValidationError(msg)
            u =authenticate(username = cleaned_data['username'], password = cleaned_data['password'])
            if u == None:
                    msg = _("Username or Password is incorrect")
                    self.add_error('username', msg)

            return cleaned_data

Answer 1

Can you post your view and template code? Without seeing either of those, I assume either your template needs to display the errors or your view is not handling the form, though I haven't used Django Crispy Forms.

{{ form.non_field_errors }}
{{ form.username.errors }}

FYI, the preferred way to handle error checking is to create a clean function for each field and have it raise a ValidationError when there is a problem. This will then be a field error (second line above).

def clean_password(self):
    data = self.cleaned_data.get('password')
    if not data:
        raise ValidationError(_("Please enter a password"))

Also, since you're just checking that a field is there, so you could set required=True for each required field and skip the manual validation.

class LoginForm(forms.Form):
    username = forms.CharField(label=('UserName'), required=True,
        widget = forms.TextInput(attrs={'placeholder': _('Username')})
    )
    password = forms.CharField(label=('Password'), required=True,
        widget=forms.PasswordInput(attrs={'placeholder' : _('Password') }),
    )

See the documentation for more info: https://docs.djangoproject.com/en/dev/topics/forms/#customizing-the-form-template