Django validate unique charfield in admin console

Question

I have 2 models with a CharField called path . On one of them I need to force it to end with / and on the other one anything but / . Also this field has to be unique and indexed. Here is the solution I came up with so far:

Dir model (must end in '/')

#   The path for sorting, e.g. /stuff/00-1/. Must be unique and is indexed for performance.
path = models.CharField(max_length=75, unique=True, db_index=True, blank=False, validators=RegexValidator(regex=r'^/[A-Za-z0-9/-_]+/$', message="Please enter a valid Dir Path")) 
...   
def save(self, *args, **kwargs):
    #   If the path does not end in "/" add it.
    if not self.path.endswith("/"):
        self.path += "/"
    if not self.path.startswith("/"):
        self.path = "/" + self.path
    #  print the result
    print("Saving path {}".format(self.path))
    super(Dir, self).save(*args, **kwargs)  # Call the "real" save() method.

I have attempted a try except around the call to super() however that changes nothing. How to I tell the admin console to validate the data so I get a not unique error before it saves and crashes so the admin can change it?

TL;DR how do I get the red line to appear above a charfeild in the admin console if it fails custom regex validation?

Answer 1

For custom validation in admin, you need a custom form for it in order to code your specific logic. save() method in django is never a good place to do validation because it doesn't return anything to the user form. Check django doc on how to have your own form for django admin . Check also how to validate a django form .