web-auth-sdk 0.2.0

authorization SDK used to build protected Web APIs

web-auth-sdk

The web-auth-sdk is an authorization SDK that is used to build protected Web APIs. It provides the ability to intercept incoming requests and inject custom logic for authentication and authorization before the request reaches the view function.

In addition, it supports Google OAuth2 for logging in and session logging in.

To access protected APIs, clients should authenticate by passing credentials or authorizations. For example, a JWT key can be used as follows:

  curl 'http://api.example.com/resources' -H 'Authorization: Bearer eyJ1c2VyX2lkIjoxLCJwZXJtaXNzaW9uX2JpdG'
  curl 'http://api.example.com/resources?access_token=eyJ1c2VyX2lkIjoxLCJwZXJtaXNzaW9uX2JpdG'
  curl 'http://api.example.com/resources' --cookie 'access_token=eyJ1c2VyX2lkIjoxLCJwZXJtaXNzaW9uX2JpdG'

Requirements

• Python 3.8+
• FastAPI 0.80+ (optional)
• Django 4.0+ (optional)
• Flask 2.0+ (optional)

Installation

pip install web-auth-sdk

Permission Representation

1. Permission list, located at usr/etc/permissions.json file:

   permissions = [
       {'bitmask_idx': 0, 'codename': 'add_order', 'name': 'Can add order', 'service': 'order'},
       {'bitmask_idx': 1, 'codename': 'change_order', 'name': 'Can change order', 'service': 'order'},
       {'bitmask_idx': 2, 'codename': 'delete_order', 'name': 'Can delete order', 'service': 'order'},
       {'bitmask_idx': 3, 'codename': 'view_order', 'name': 'Can view order', 'service': 'order'},
       {'bitmask_idx': 4, 'codename': 'add_tickettype', 'name': 'Can add ticket type', 'service': 'order'},
       {'bitmask_idx': 5, 'codename': 'change_tickettype', 'name': 'Can change ticket type', 'service': 'order'},
       {'bitmask_idx': 6, 'codename': 'view_tickettype', 'name': 'Can view ticket type', 'service': 'order'},
       {'bitmask_idx': 7, 'codename': 'delete_tickettype', 'name': 'Can delete ticket type', 'service': 'order'},
   ]
   

2. How to grant permissions?

   Permissions are encoded using a bitmask of length n that is a multiple of 24. Each permission is represented by a 1 on the corresponding bitmask_idx-th position in the bitmask, indicating that the permission is granted.

3. Base64-encoded the bitmask

   Bitmask	Base64-encoded
   111111111111111111111111111111110111111101111111	/////39/

4. Decoded/Encoded JWT

   {
     "user_id": 1,
     "permission_bitmask": "/////39/",
     "iat": 1678798980,
     "exp": 1678800187
   }
   

   eyJ1c2VyX2lkIjoxLCJwZXJtaXNzaW9uX2JpdG1hc2siOiIvLy8vLzM5LyIsImlhdCI6MTY3ODc5ODk4MCwiZXhwIjoxNjc4ODAwMTg3fQ
   

Development

• FastAPI

  import web_auth
  
  
  web_auth.configure()
  
  @fastapi.get('/tickets')
  @web_auth.permissions('view_ticket') # Iterable[str] are acceptable
  async def list_tickets() -> list[object]: 
      pass
  

• Django

  import web_auth
  from web_auth.django import DjangoBridge
  
  
  web_auth.configure(bridge_class=DjangoBridge)
  
  @web_auth.permissions('view_ticket')
  def list_tickets(request) -> list[object]: 
      pass
  
  urlpatterns = [django.urls.path('list-tickets', list_tickets)]
  

• Flask

  import web_auth
  from web_auth.flask import FlaskBridge
  
  
  web_auth.configure(bridge_class=FlaskBridge)
  
  @flask.route('/tickets', methods=['GET'])
  @web_auth.permissions('view_ticket')
  def list_tickets() -> list[object]: 
      pass
  

• Use instanced context

  import web_auth
  
  
  context = web_auth.build_context()  
  
  @fastapi.get('/tickets')
  @context.permissions('view_ticket')
  async def list_tickets() -> list[object]: 
      pass
  

• Implement access control & retrieve the consumer info

  import fastapi
  import web_auth
  
  
  context = web_auth.build_context()
  
  @fastapi.get('/profile')
  @context.permissions()
  def get_profile(request: fastapi.Request, consumer: web_auth.Consumer) -> web_auth.Consumer:
      # raise `web_auth.AuthException` if the consumer does not have permission
      context.bridge.access_control(
          request=request, 
          permissions={'view_ticket'},
          aggregation_type=web_auth.PermissionAggregationTypeEnum.ALL,
      )
      return consumer
  

• Customization

  1. Permission Storage

  from typing import Optional
  
  import fastapi
  import requests
  
  from web_auth import build_context, Storage, PermissionModel, Context
  
  
  class RESTStorage(Storage):
      def __init__(self, ttl: int, url: str, context: Optional[Context] = None):
          self.url = url
          super().__init__(ttl=ttl, context=context)
  
      def _load_permissions(self) -> list[PermissionModel]:
          return [PermissionModel(**r) for r in requests.get(self.url).json()]
  
  my_context = build_context(
      storage_class=RESTStorage,
      storage_params={'ttl': 60, 'url': 'http://api.example.com/permissions?format=json'},
  )
  
  @fastapi.get('/tickets')
  @my_context(['view_ticket', 'change_ticket'])
  def get_tickets() -> list[object]:
      pass
  

  2. Authentication

  import fastapi
  import pydantic
  
  from web_auth import build_context, Config
  from web_auth.fastapi import FastapiBridge
  
  
  class MyConsumer(pydantic.BaseModel):
      user_id: int
  
  class MyFastapiBridge(FastapiBridge):
      consumer_class = MyConsumer
  
      def authenticate(self, request: fastapi.Request) -> tuple[MyConsumer, str]:
          # your authenticate logic
          return MyConsumer(user_id=1), 'JWT'
  
  my_context = build_context(
      bridge_class=MyFastapiBridge,
      storage_class=Config.DEFAULT_STORAGE_CLASS,
      storage_params=Config.DEFAULT_STORAGE_PARAMS,
  )
  
  @fastapi.get('/profile')
  @my_context([])
  def get_profile(consumer: MyConsumer) -> MyConsumer:
      return consumer
  

  3. Authorization

  import fastapi
  
  from web_auth import build_context, Authorization, Consumer, PermissionAggregationTypeEnum
  from web_auth.fastapi import FastapiBridge 
  
  
  class MyAuthorization(Authorization):
      def authorize(
          self,
          consumer: Consumer,
          permissions: set[str],
          aggregation_type: PermissionAggregationTypeEnum,
      ):
          permission_models = self.context.storage.get_permissions()
          # Checks whether the `consumer` has the `permissions` in `permission_models`
  
  class MyFastapiBridge(FastapiBridge):
      authorization_class = MyAuthorization
  
  my_context = build_context(
      bridge_class=MyFastapiBridge,
  )
  
  @fastapi.get('/tickets')
  @my_context(['view_ticket', 'change_ticket'])
  def get_tickets() -> list[object]:
      pass
  

• Oauth2 client

  1. Install apps to settings.py

  INSTALLED_APPS = [
      'web_auth.django'
  ]
  

  2. Register url to urls.py

  urlpatterns = [
      django.urls.path('', django.urls.include('web_auth.django.urls')),
  ]
  

  3. Login with Google
  • http://api.example.com/google/login
  • http://api.example.com/google/auth
  4. Session Login
  • http://api.example.com/session/csrftoken
  • http://api.example.com/session/login