Deprecate built-in Cache system

[lepture]

Per pallets/werkzeug#1249

Werkzeug is going to deprecate werkzeug.contrib.cache, there is not an easy way to maintain a built-in cache system for Flask. In this case, it is suggested that you pass a cache instance as parameter.

Cache Interface

You need to create your own cache object. A cache interface should contain these methods:

• .get(key)
• .delete(key)
• .set(key, value, timeout=None)

Flask OAuth Client

If you need to support OAuth 1, cache is required. You can pass the cache object when initializing or init_app:

from authlib.flask.client import OAuth

oauth = OAuth(app, cache=cache)

# or initialize lazily
oauth = OAuth()
oauth.init_app(app, cache=cache)

Flask OAuth 1 Server

Cache is used a lot in OAuth 1 provider. Instead of passing cache as a parameter,
you can use the helper functions to register hooks:

from authlib.flask.oauth1 import AuthorizationServer, ResourceProtector
from authlib.flask.cache import (
    register_nonce_hooks,
    register_temporary_credential_hooks,
    create_exists_nonce_func
)

# 1. AuthorizationServer
server = AuthorizationServer(app, Client)
register_nonce_hooks(server, cache)
register_temporary_credential_hooks(server, cache)

# 2. ResourceProtector
require_oauth = ResourceProtector(
    app, Client,
    query_token=query_token,
    exists_nonce=create_exists_nonce_func(cache)
)

Flask OAuth 2 Server

Pass cache instead of Flask app into register_cache_authorization_code:

from authlib.flask.oauth2 import register_cache_authorization_code

register_cache_authorization_code(cache, server, create_access_token)

---

The built-in cache system will be removed in version 0.7.