Django snippets: Use email addresses for user name

Use email addresses for user name

from django.contrib.auth.models import User
from django.core.validators import email_re

class BasicBackend:
    def get_user(self, user_id):
        try:
            return User.objects.get(pk=user_id)
        except User.DoesNotExist:
            return None

class EmailBackend(BasicBackend):
    def authenticate(self, username=None, password=None):
        #If username is an email address, then try to pull it up
        if email_re.search(username):
            try:
                user = User.objects.get(email=username)
            except User.DoesNotExist:
                return None
        else:
            #We have a non-email address username we should try username
            try:
                user = User.objects.get(username=username)
            except User.DoesNotExist:
                return None
        if user.check_password(password):
            return user

Django's built in authentication system requires the username to be alpha-numeric only. Therefore, email addresses are invalid. However, in many cases, you would like to use an email address as the username. This snippet allows you to do so. It has the added benefit that if you want to continue using the regular username format, you can do that too. It's the best of both worlds!

To make sure propoer credit is given, this code is modified from a django group posting from Vasily Sulatskov.

To use this file, save it in your project as something like: email-auth.py

Then, add the following lines to your settings.py file:

AUTHENTICATION_BACKENDS = (
    'yourproject.email-auth.EmailBackend',
 )

You can see a full implementation here

Author:: chris
Posted:: March 2, 2007
Language:: Python
Tags:: authentication
Score:: 39 (after 41 ratings)

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bluszcz (on March 15, 2007):

Does it works admin app? In my case not :)

robbie (on April 16, 2007):

This is certainly a useful snippet, but it seems a little over complicated. What's wrong with just:

from django.contrib.auth.backends import ModelBackend
from django.core.validators import email_re
from django.contrib.auth.models import User

class EmailBackend(ModelBackend):
    def authenticate(self, username=None, password=None):
        if email_re.search(username):
            try:
                user = User.objects.get(email=username)
                if user.check_password(password):
                    return user
            except User.DoesNotExist:
                return None
        return None

...and then just adding it in front of Django's ModelBackend?

AUTHENTICATION_BACKENDS = (
    "emailauth.EmailBackend",
    "django.contrib.auth.backends.ModelBackend",
)

adurdin (on May 4, 2007):

The admin login view displays a message "Your email address is not your username" if you attempt to login with an email address and password that do not match (e.g. mistyped the password).

Paperface (on May 14, 2007):

adurdin: Alter your template registration/login.html to reflect the change in authentication method.

chris: Just thought I'd let you know, I'm using this and it seems to work very well

Thanks

zgoda (on July 12, 2007):

The problem is, the email field in User model is not unique, so you have to do 2 things: monkeypatch your database by addinng necessary constraint to the email field and generate some-kind-of-unique username. Unfortunately, the field is only allowed to keep 30 characters, so you cann't just use munged email or md5 hash for username...

zgoda (on August 28, 2007):

More problems with this. Users of our applications keep reporting me various places in django's own admin where "weird" usernames are shown. Sometimes it's really hard to customize admin templates to display something other than default __str__ provided by Django. I'm thinking on dynamic replacing __str__ in django.contrib.auth.models.User, maybe using signals?

mawoodall (on November 9, 2007):

The key to having this work with user object functions like 'has_perm()' and the admin interface is that you have to add both the new and default backends to your settings file:

'AUTHENTICATION_BACKENDS = ( 'yourproject.email-auth.EmailBackend', "django.contrib.auth.backends.ModelBackend", ) '

cogat (on January 17, 2008):

One other thing - the max_length for username in contrib.auth.forms.login is 30. It should be increased to the length of the email field, 75 characters by default.

Rich (on February 7, 2008):

One other thing - the max_length for username in contrib.auth.forms.login is 30. It should be increased to the length of the email field, 75 characters by default

Sorry if this is a dumb question, but what would be the correct way to do that?

lars.yencken (on May 9, 2008):

Rich: Probably two ways. Firstly, you can manually alter the database yourself after running syncdb. In fact, you could hook a callback onto the post_syncdb signal to do it automatically every time. Secondly, you could simply edit the django source which is installed to change the field width. Find and edit the User class in django/contrib/auth/models.py.

crucialfelix (on June 28, 2008):

lars: I misread this the first time too. cogat is saying the the FORM field is limited to 30 chars. nothing to do with the db. the database still stores a username (whatever you want, random, truncated version of email etc.) but the EmailBackend checks against the EMAIL in the db. the db does not have to be altered thus.

jturnbull (on August 1, 2008):

Also see this blog post which does a similar thing, but looks for a separate "email" argument to the "authenticate" method.

vizualbod (on August 30, 2008):

In Django 1.0 (since beta2) replace

from django.core.validators import email_re

with

from django.forms.fields import email_re

Frank, web development Manchester

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Use email addresses for user name

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