Django OIDC Provider

OpenID Connect 1.0 are built custom grant types and grant extensions. You need to read the Authorization Server chapter at first.

Looking for OpenID Connect Client? Head over to Django OAuth Client.

Understand JWT

OpenID Connect 1.0 uses JWT a lot. Make sure you have the basic understanding of JOSE Guide.

For OpenID Connect, we need to understand at lease four concepts:

  1. alg: Algorithm for JWT

  2. key: Private key for JWT

  3. iss: Issuer value for JWT

  4. exp: JWT expires time

alg

The algorithm to sign a JWT. This is the alg value defined in header part of a JWS:

{"alg": "RS256"}

The available algorithms are defined in RFC7518: JSON Web Algorithms, which are:

  • HS256: HMAC using SHA-256

  • HS384: HMAC using SHA-384

  • HS512: HMAC using SHA-512

  • RS256: RSASSA-PKCS1-v1_5 using SHA-256

  • RS384: RSASSA-PKCS1-v1_5 using SHA-384

  • RS512: RSASSA-PKCS1-v1_5 using SHA-512

  • ES256: ECDSA using P-256 and SHA-256

  • ES384: ECDSA using P-384 and SHA-384

  • ES512: ECDSA using P-521 and SHA-512

  • PS256: RSASSA-PSS using SHA-256 and MGF1 with SHA-256

  • PS384: RSASSA-PSS using SHA-384 and MGF1 with SHA-384

  • PS512: RSASSA-PSS using SHA-512 and MGF1 with SHA-512

The HMAC using SHA algorithms are not suggested since you need to share secrets between server and client. Most OpenID Connect services are using RS256.

key

A private key is required to generate JWT. The key that you are going to use dependents on the alg you are using. For instance, the alg is RS256, you need to use an RSA private key. It can be set with:

key = '''-----BEGIN RSA PRIVATE KEY-----\nMIIEog...'''

# or in JWK format
key = {"kty": "RSA", "n": ...}

iss

The iss value in JWT payload. The value can be your website name or URL. For example, Google is using:

{"iss": "https://accounts.google.com"}

Code Flow

OpenID Connect authorization code flow relies on the OAuth2 authorization code flow and extends it. In OpenID Connect, there will be a nonce parameter in request, we need to save it into database for later use. In this case, we have to rewrite our AuthorizationCode db model:

class AuthorizationCode(Model, AuthorizationCodeMixin):
    user = ForeignKey(User, on_delete=CASCADE)
    client_id = CharField(max_length=48, db_index=True)
    code = CharField(max_length=120, unique=True, null=False)
    redirect_uri = TextField(default='', null=True)
    response_type = TextField(default='')
    scope = TextField(default='', null=True)
    auth_time = IntegerField(null=False, default=now_timestamp)

    # add nonce
    nonce = CharField(max_length=120, default='', null=True)

    # ... other fields and methods ...

OpenID Connect Code flow is the same as Authorization Code flow, but with extended features. We can apply the OpenIDCode extension to AuthorizationCodeGrant.

First, we need to implement the missing methods for OpenIDCode:

from authlib.oidc.core import grants, UserInfo

class OpenIDCode(grants.OpenIDCode):
    def exists_nonce(self, nonce, request):
        try:
            AuthorizationCode.objects.get(
                client_id=request.client_id, nonce=nonce
            )
            return True
        except AuthorizationCode.DoesNotExist:
            return False

    def get_jwt_config(self, grant):
        return {
            'key': read_private_key_file(key_path),
            'alg': 'RS512',
            'iss': 'https://example.com',
            'exp': 3600
        }

    def generate_user_info(self, user, scope):
        user_info = UserInfo(sub=str(user.pk), name=user.name)
        if 'email' in scope:
            user_info['email'] = user.email
        return user_info

Second, since there is one more nonce value in AuthorizationCode data, we need to save this value into database. In this case, we have to update our AuthorizationCodeGrant.save_authorization_code method:

class AuthorizationCodeGrant(_AuthorizationCodeGrant):
    def save_authorization_code(self, code, request):
        # openid request MAY have "nonce" parameter
        nonce = request.data.get('nonce')
        client = request.client
        auth_code = AuthorizationCode(
            code=code,
            client_id=client.client_id,
            redirect_uri=request.redirect_uri,
            scope=request.scope,
            user=request.user,
            nonce=nonce,
        )
        auth_code.save()
        return auth_code

Finally, you can register AuthorizationCodeGrant with OpenIDCode extension:

# register it to grant endpoint
server.register_grant(AuthorizationCodeGrant, [OpenIDCode(require_nonce=True)])

The difference between OpenID Code flow and the standard code flow is that OpenID Connect request has a scope of “openid”:

GET /authorize?
response_type=code
&scope=openid%20profile%20email
&client_id=s6BhdRkqt3
&state=af0ifjsldkj
&redirect_uri=https%3A%2F%2Fclient.example.org%2Fcb HTTP/1.1
Host: server.example.com

With the example above, you will also have to change the scope of your client in your application to something like openid profile email.

Now that you added the openid scope to your application, an OpenID token will be provided to this app whenever a client asks for a token with an openid scope.

Implicit Flow

The Implicit Flow is mainly used by Clients implemented in a browser using a scripting language. You need to implement the missing methods of OpenIDImplicitGrant before register it:

from authlib.oidc.core import grants

class OpenIDImplicitGrant(grants.OpenIDImplicitGrant):
    def exists_nonce(self, nonce, request):
        try:
            AuthorizationCode.objects.get(
                client_id=request.client_id, nonce=nonce)
            )
            return True
        except AuthorizationCode.DoesNotExist:
            return False

    def get_jwt_config(self):
        return {
            'key': read_private_key_file(key_path),
            'alg': 'RS512',
            'iss': 'https://example.com',
            'exp': 3600
        }

    def generate_user_info(self, user, scope):
        user_info = UserInfo(sub=user.id, name=user.name)
        if 'email' in scope:
            user_info['email'] = user.email
        return user_info

server.register_grant(OpenIDImplicitGrant)

Hybrid Flow

Hybrid flow is a mix of the code flow and implicit flow. You only need to implement the authorization endpoint part, token endpoint will be handled by Authorization Code Flow.

OpenIDHybridGrant is a subclass of OpenIDImplicitGrant, so the missing methods are the same, except that OpenIDHybridGrant has one more missing method, that is save_authorization_code. You can implement it like this:

from authlib.oidc.core import grants

class OpenIDHybridGrant(grants.OpenIDHybridGrant):
    def save_authorization_code(self, code, request):
        # openid request MAY have "nonce" parameter
        nonce = request.data.get('nonce')
        client = request.client
        auth_code = AuthorizationCode(
            code=code,
            client_id=client.client_id,
            redirect_uri=request.redirect_uri,
            scope=request.scope,
            user=request.user,
            nonce=nonce,
        )
        auth_code.save()
        return auth_code

    def exists_nonce(self, nonce, request):
        try:
            AuthorizationCode.objects.get(
                client_id=request.client_id, nonce=nonce)
            )
            return True
        except AuthorizationCode.DoesNotExist:
            return False

    def get_jwt_config(self):
        return {
            'key': read_private_key_file(key_path),
            'alg': 'RS512',
            'iss': 'https://example.com',
            'exp': 3600
        }

    def generate_user_info(self, user, scope):
        user_info = UserInfo(sub=user.id, name=user.name)
        if 'email' in scope:
            user_info['email'] = user.email
        return user_info

# register it to grant endpoint
server.register_grant(OpenIDHybridGrant)

Since all OpenID Connect Flow requires exists_nonce, get_jwt_config and generate_user_info methods, you can create shared functions for them.