FastAPI JWT Authentication

This skill provides a robust and reusable solution for implementing JWT (JSON Web Token) authentication in FastAPI applications. It includes a Python script with core authentication logic and a detailed guide with integration patterns.

Bundled Resources

This skill comes with the following pre-packaged resources:

• scripts/jwt_auth.py: A Python script containing all the core utility functions for handling JWTs. This includes:

  • Password hashing and verification (passlib).
  • Access and refresh token creation (python-jose).
  • Token decoding and validation.
  • A FastAPI dependency (get_current_user) for protecting endpoints.

• references/fastapi_integration.md: A comprehensive guide with code examples and patterns for integrating the authentication logic into a FastAPI application.

Workflow

When a user asks to implement JWT authentication in FastAPI, follow this workflow:

1. Understand the User's Requirements

First, clarify the specific needs of the user:

• What custom claims should be in the token (e.g., user_id, roles, email)?
• Do they need role-based access control (RBAC)?
• Do they have an existing user model and database setup?

2. Review the Core Logic (If Necessary)

The core, reusable authentication logic is in scripts/jwt_auth.py. You should not need to modify this file in most cases. Familiarize yourself with the functions it provides:

• create_access_token() and create_refresh_token()
• verify_password() and get_password_hash()
• get_current_user() (the main dependency for protected routes)

3. Implement the Integration Patterns

The primary guide for implementation is references/fastapi_integration.md. Read this file carefully. It contains all the necessary code patterns to add authentication to the user's application.

Follow the steps outlined in the reference guide:

1. Setup and Dependencies: Instruct the user on installing the required packages.
2. Pydantic Models: Help the user create or update their Pydantic models for users and tokens.
3. Login Endpoint: Use the pattern from the guide to create a /token endpoint that issues access and refresh tokens.
4. Protected Endpoints: Use the get_current_user dependency to protect routes that require authentication.
5. Role-Based Access: If required, use the decorator pattern from the guide to implement role-based access control.
6. Token Refresh: Implement a /refresh endpoint so clients can get new access tokens.

Your goal is to adapt the patterns from references/fastapi_integration.md to the user's existing codebase, providing them with a fully working authentication system.