sanic-cookies 0.4.3

Cookies and Session Management for Sanic

Sanic Cookies

Much of the code here is borrowed from sanic_session.

I wanted to make some changes that would break a big part of sanic_session's API, so I decided to create this repo instead.

Sanic cookies supports both client side and server side cookies.

Main deviations from sanic_session are

• Interfaces are only responsible for reading/writing the SessionDict:

  Session management logic is handled by the Session object

• No race conditions:

  By using:

  async with request['session']:
      request['session']['foo'] = 'bar'
  

  instead of:

  request['session']['foo'] = 'bar'
  

  It is still however possible to use the session_dict without a context manager, but it will raise some warnings, unless it's explicitly turned off (warn_lock=False)

  Note:

  The locking mechanism used here only keeps track of locks on a thread-level, which means, an application that is horizontally scaled or one that runs on more than one process won't fully benefit from the locking mechanism that sanic-cookies currently has in place and might encounter some race conditions. I have plans to introduce a distributed locking mechanism. Probably using something like: Aioredlock. But for now, you should know that the locking mechanism that is currently in place will not work in a multi-process environment.

• A simpler implementation of SessionDict that helps me sleep in peace at night. (Probably less performant)

• In memory interface schedules cleanup to avoid running out of memory

• Encrypted client side cookie interface

• Ability to add more than one interface to the same session

• Authenticated Session implementation

Setup ⚙️

$ pip install sanic_cookies

Quick Start

from sanic_cookies import Session, InMemory
from sanic import Sanic

app = Sanic()
Session(app, master_interface=InMemory())

@app.route('/')
async def handler(request):
    async with request['session'] as sess:
        sess['foo'] = 'bar'

Usage

Running multiple interfaces

from sanic_cookies import Session, InMemory, Aioredis
from sanic import Sanic

inmem = InMemory()
aioredis = AioRedis(aioredis_pool_instance)
app = Sanic()
sess = Session(app, master_interface=inmem, session_name='my_1st_sess')
sess.add_interface(aioredis)

@app.route('/')
async def index(request):
    async with request['my_1st_session'] as sess:
        sess['foo'] = 'bar'
        # At this point 'foo' = 'bar' is written both to the inmemory
        # interface and the aioredis interface

    async with request['my_1st_session'] as sess:
        # When reading, your session will always read from the "master_interface"
        # In that case it's the inmem interface
        assert sess['foo'] == 'bar'
    # Such pattern can be useful in many cases 
    # e.g. you want to share your session information with an analytics team

Running multiple sessions

from sanic_cookies import Session, AuthSession, InMemory, InCookieEncrypted, AioRedis
from sanic import Sanic

inmem = InMemory()
aioredis = Aioredis(aioredis_pool_instance)
incookie = InCookieEncrypted(b'fernetsecretkey')

app = Sanic()

incookie_session = Session(
    app,
    master_interface=incookie,
    session_name='incookiesess',
    cookie_name='INCOOKIE'
)

generic_session = Session(
    app,
    master_interface=inmem,
    session_name='session',
    cookie_name='SESSION'
)

auth_session = AuthSession(
    app,
    master_interface=aioredis,
    session_name='auth_session',
    cookie_name='SECURE_SESSION'
)

# for production (HTTPs) set `secure=True` in your auth_session,
# but this will fail in local development

@app.route('/')
async def index(request):
    async with request['incookie_session'] as sess:
        sess['foo'] = 'bar'

    async with request['session'] as sess:
        sess['bar'] = 'baz'

    async with request['auth_session'] as sess:
        sess['baz'] = 'foo'

AuthSession

Following up on the previous example:

from sanic_cookies import login_required

@app.route('/login')
async def login(request):
    # 1. User verification logic

    # both will work (Whatever is json serializble will)
    # If you want to pickle an object simply change the default
    # encoder&decoder in the interfaces plugged in to your AuthSession
    authorized_user = 123 
    authorized_user = {'user_id': 123, 'email': '[e-mail]'}

    # 2. Login user

    # Here we access the session object
    # (not the session dict that is accessible from the request) from the app
    await request.app.exts.auth_session.login_user(request, authorized_user)

    # 3. Use the session dict safely and exclusively for the logged in user

    async with request['auth_session'] as sess:
        sess['foo'] = 'bar'
        current_user = sess['current_user']
    assert current_user == await request.app.exts.auth_session.current_user()

@app.route('/logout')
async def logout(request):
    async with request['auth_session'] as sess:
        assert sess['foo'] == 'bar'  # From before

    await request.app.exts.auth_session.logout_user(request)  # Resets the session

    async with request['auth_session'] as sess:
        assert sess.get('foo') is None  # should never fail
        assert sess.get('current_user') is None  # should never fail

@app.route('/protected')
@login_required()
async def protected(request):
    assert await request.app.exts.auth_session.current_user() is not None  # should never fail

Interfaces available

1. In memory

   from sanic_cookies import Session, InMemory
   from sanic import Sanic
   
   interface = InMemory()
   app = Sanic()
   Session(app, master_interface=interface)
   
   # You can skip this part if you don't want scheduled interface cleanup
   @app.listener('before_server_start')
   def init_inmemory(app, loop):
       interface.init()
   @app.listener('after_server_stop')
   def kill_inmemory(app, loop):
       interface.kill()
   
   @app.route('/')
   async def handler(request):
       async with request['session'] as sess:
           sess['foo'] = 'bar'
   

2. Aioredis

   from aioredis import Aioredis
   from sanic_cookies import Aioredis as AioredisInterface
   from sanic import Sanic
   
   app = Sanic()
   aioredis_pool_instance = Aioredis()
   aioredis = AioredisInterface(aioredis_pool_instance)
   Session(app, master_interface=interface)
   
   @app.route('/')
   async def handler(request):
       async with request['session'] as sess:
           sess['foo'] = 'bar'
   

3. Encrypted in-cookie (using the amazing cryptography.Fernet library)

   i. Open a Python terminal and generate a new Fernet key:

   >>> from cryptography.fernet import Fernet
   
   >>> SESSION_KEY = Fernet.generate_key()
   
   >>> print(SESSION_KEY)
   
   b'copy me to your sanic app and keep me really secure'
   

   ii. Write your app

   from sanic import Sanic
   from sanic_cookies import Session, InCookieEncrypted
   
   app = Sanic()
   app.config.SESSION_KEY = SESSION_KEY
   
   Session(
       app,
       master_interface=InCookieEncrypted(app.config.SESSION_KEY),
   )
   
   @app.route('/')
   async def handler(request):
       async with request['session'] as sess:
           sess['foo'] = 'bar'
   

4. Gino-AsyncPG (Postgres 9.5+):

   i. Manually create a table:

   CREATE TABLE IF NOT EXISTS sessions
   (
       created_at timestamp without time zone NOT NULL,
       expires_at timestamp without time zone,
       sid character varying,
       val character varying,
       CONSTRAINT sessions_pkey PRIMARY KEY (sid)
   );
   

   ii. Add the interface:

   from sanic import Sanic
   from gino.ext.sanic import Gino
   from sanic_cookies import GinoAsyncPG
   
   from something_secure import DB_SETTINGS
   
   app = Sanic()
   app.config.update(DB_SETTINGS)
   db = Gino()
   db.init_app(app)
   
   interface = GinoAsyncPG(client=db)
   auth_session = AuthSession(app, master_interface=interface)
   
   if __name__ == '__main__':
       app.run(host='127.0.0.1', port='8080')
   

Sessions available

1. Session (A generic session interface)
2. AuthSession (A session interface with login_user, logout_user, current_user logic)

Other pluggable parts

1. Encoders and Decoders (Default to ujson)
2. SID factory (Default to uuid.uuid4)
3. Session dict implementation

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