ensure that username not all numeric #321

src/chigame/users/models.py

@@ -2,6 +2,7 @@
 from django.contrib.auth.models import AbstractUser
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator
 from django.urls import reverse
 from django.utils import timezone
@@ -10,6 +11,14 @@
 from chigame.users.managers import UserManager
 
 
+def validate_username(value):
+    """
+    Validate that the username is not all numeric.
+    """
+    if value.isdigit():
+        raise ValidationError(_("Username cannot be all numbers."), code="invalid_username")
+
+
 class User(AbstractUser):
     """
     Default custom user model for ChiGame.
@@ -22,14 +31,20 @@ class User(AbstractUser):
     first_name = None  # type: ignore
     last_name = None  # type: ignore
     email = models.EmailField(_("email address"), unique=True)
-    username = models.CharField(_("username"), max_length=255, unique=True, blank=True, null=True)
+    username = models.CharField(
+        _("username"), max_length=255, unique=True, blank=True, null=True, validators=[validate_username]
+    )
     tokens = models.PositiveSmallIntegerField(validators=[MaxValueValidator(3)], default=1)
 
     USERNAME_FIELD = "email"
     REQUIRED_FIELDS = []
 
     objects = UserManager()
 
+    def clean(self) -> None:
+        super().clean()
+        self.validate_username(self.username)
+
     def get_absolute_url(self) -> str:
         """Get URL for user's detail view.