full oidc example with autoconfiguration (#222)

Author: styk-tv

examples/oidc.py

@@ -0,0 +1,137 @@
+from flask import Flask, jsonify
+from flask_restful import Api
+import requests
+import json
+from jwt.algorithms import RSAAlgorithm
+from functools import wraps
+from flask_jwt_extended import (
+    JWTManager, verify_jwt_in_request, get_raw_jwt, current_user
+)
+import config
+
+
+# Setup Flask Server
+app = Flask(__name__)
+app.config.from_object(config.Config)
+api = Api(app)
+
+# ==== SETUP
+# Set OIDC entries for auto-discovery
+# Naming of 4 key input variables borrowed from Kubernetes (https://kubernetes.io/docs/reference/access-authn-authz/authentication/)
+# This was tested with Red Hat's https://www.keycloak.org/ but should work with any OIDC provider like Auth0, Octa, Google, Microsoft etc.
+
+# Issuer + Realm
+OIDC_ISSUER_URL = 'https://my-identity-server.example/auth/realms/master'
+
+# Client ID (Audience)
+OIDC_CLIENT_ID = 'example.my-identity-server'
+
+# Token variable holding unique username
+OIDC_USERNAME_CLAIM = 'email'
+
+# Token list variable holding groups that user belongs to (for role-based-access-control)
+# idea here is to have few but could be hundreds of groups, based on which groups user belongs to, grants them access to various endpoints
+# in identity server this is usually mapped directly to ldap, so ldap group membership defines which endpoints user can access
+# https://www.keycloak.org/docs/latest/server_admin/index.html#_ldap_mappers, but remember groups don't have to come from ldap
+# group mapper was setup for flat group structure not to include any prefixes so if you have to do that, please update code in group_required method
+OIDC_GROUPS_CLAIM = 'groups'
+
+# ==== END OF SETUP
+
+
+# Helper Methods
+def urljoin(*args):
+    """
+    Joins given arguments into an url. Trailing but not leading slashes are
+    stripped for each argument.
+    """
+
+    return "/".join(map(lambda x: str(x).rstrip('/'), args))
+
+
+def token_required(fn):
+    @wraps(fn)
+    def wrapper(*args, **kwargs):
+        verify_jwt_in_request()
+        return fn(*args, **kwargs)
+    return wrapper
+
+
+def group_required(group=''):
+    def decorator(fn):
+        @wraps(fn)
+        def wrapper(*args, **kwargs):
+            # standard flask_jwt_extended token verifications
+            verify_jwt_in_request()
+
+            # custom group membership verification
+            groups = get_raw_jwt()[OIDC_GROUPS_CLAIM]
+            if group not in groups:
+                return jsonify({'result': "user not in group required to access this endpoint"}), 401
+            return fn(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+# Setup Token Verification
+# force use of RS265
+app.config['JWT_ALGORITHM'] = 'RS256'
+
+# retrieve master openid-configuration endpoint for issuer realm
+oidc_config = requests.get(urljoin(OIDC_ISSUER_URL, '.well-known/openid-configuration'), verify=False).json()
+
+# retrieve data from jwks_uri endpoint
+oidc_jwks_uri = requests.get(oidc_config['jwks_uri'], verify=False).json()
+
+# retrieve first jwk entry from jwks_uri endpoint and use it to construct the RSA public key
+app.config['JWT_PUBLIC_KEY'] = RSAAlgorithm.from_jwk(json.dumps(oidc_jwks_uri['keys'][0]))
+
+# audience is oidc client id (can be array starting https://github.com/vimalloc/flask-jwt-extended/issues/219)
+app.config['JWT_DECODE_AUDIENCE'] = OIDC_CLIENT_ID
+
+# name of token entry that will become distinct flask identity username
+app.config['JWT_IDENTITY_CLAIM'] = OIDC_USERNAME_CLAIM
+jwt = JWTManager(app)
+
+
+# TEST ENDPOINTS
+@app.route('/anonymous', methods=['GET'])
+def get_anonymous():
+    return jsonify({'result': "anonymous ok"}), 200
+
+
+@app.route('/token-protected', methods=['GET'])
+@token_required
+def get_protected_by_token():
+    return jsonify({'result': "protected by token ok"}), 200
+
+
+@app.route('/group-protected', methods=['GET'])
+@group_required('api-access')  # currently one, could be one of or multiple required depending on your needs
+def get_protected_by_group():
+    return jsonify({'result': "protected by token AND group membership ok"},
+                   {'user': current_user.username}
+                   ), 200
+
+
+# Identity User Class
+class User:
+    username = None
+
+    def __init__(self):
+        pass
+
+
+# User Class to get you started
+# Identity holds whatever variable in token you point at JWT_IDENTITY_CLAIM
+# good place to construct identity from token and other places, it is then available in method through current_user.<property>
+@jwt.user_loader_callback_loader
+def user_loader_callback(identity):
+    u = User()
+    u.username = identity
+    return u
+
+
+app.run(host='0.0.0.0')
+
+