Add form validation for checking email

user/forms.py

@@ -2,7 +2,6 @@ from django import forms
 from django.contrib.auth.forms import UserCreationForm
 from django.contrib.auth.models import User
 
-
 class SignUpForm(UserCreationForm):
     first_name = forms.CharField(max_length=255)
     last_name = forms.CharField(max_length=255)
@@ -11,3 +10,10 @@ class SignUpForm(UserCreationForm):
     class Meta:
         model = User
         fields = ('username', 'first_name', 'last_name', 'email', 'password1', 'password2', )
+
+    def clean_email(self):
+        email = self.cleaned_data.get('email')
+        username = self.cleaned_data.get('username')
+        if email and User.objects.filter(email=email).exclude(username=username).exists():
+            raise forms.ValidationError('User with this Email address already exists.')
+        return email
\ No newline at end of file

user/views.py

@@ -29,3 +29,9 @@ class EditProfile(UpdateView):
     slug_field = 'username'
     slug_url_kwarg = 'slug'
 
+    def clean_email(self):
+        email = self.cleaned_data.get('email')
+        username = self.cleaned_data.get('username')
+        if email and User.objects.filter(email=email).exclude(username=username).exists():
+            raise forms.ValidationError('This email address has been already used by another user.')
+        return email