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:
alg: Algorithm for JWT
key: Private key for JWT
iss: Issuer value for JWT
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.