This Python package provides a Flask decorator which adds local and remote OAuth2 (RFC-6749) validation for self-encoded JWT (RFC-7519) based Bearer (RFC-6750) access tokens.

It only covers validation logic required by resource servers (APIs) and does not provide any implementation of OAuth2 flows (e.g. authorization code flow).

Requirements

• The authorization server has to support Authorization Server Metadata (RFC-8414).
• The JWT access tokens should follow the JSON Web Token (JWT) Profile for OAuth 2.0 Access Tokens (RFC-9068).

Configuration

The minimal configuration expects the OAUTH2_ISSUER attribute being set which points to the issuer:

app.config['OAUTH2_ISSUER'] = 'https://<your-issuer>/oauth2'

This would perform local token validation after downloading the public keys (RFC-7517) from the authorization server (RFC-7800).

In case you also need to perform remote token validation (RFC-7662) an OAUTH2_CLIENT_ID and OAUTH2_CLIENT_SECRET need to be configured:

app.config['OAUTH2_CLIENT_ID'] = 'your-client-id'
app.config['OAUTH2_CLIENT_SECRET'] = 'your-client-secret'

In case your authorization server uses rotating public keys an OAUTH2_JWKS_UPDATE_INTERVAL (in seconds) could be configured to regularly download the latest public keys from the authorization server:

app.config['OAUTH2_JWKS_UPDATE_INTERVAL'] = 3600

For a more strict validation it is recommended to configure an OAUTH2_AUDIENCE to verify the token against:

app.config['OAUTH2_AUDIENCE'] = 'api://default'

Usage

To provide OAuth2 token validation to your endpoints simply add the OAuth2Decorator:

from flask_oauth2_validation import OAuth2Decorator

oauth2 = OAuth2Decorator(app)

@oauth2.requires_token()
@app.route('/protected')
def protected():
    pass

This would perform local token validation, only. To enable remote token validation you need to provide the introspect=True argument:

@oauth2.requires_token(introspect=True)
@app.route('/protected')
def protected():
    pass

In case you require one or multiple scopes to allow execution, add the scopes=[...] argument:

@oauth2.requires_token(scopes=['profile', 'email'])
@app.route('/protected')
def protected():
    pass

To use the token from within your method you can access it via the OAuth2Decorator object like:

@oauth2.requires_token()
@app.route('/protected')
def protected():
    token: dict = oauth2.token
    pass

License

MIT License

Copyright (c) 2021 Henrik Sachse

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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SOFTWARE.