FastAPI + Redis: Basic Application of Caching and State Management

Web development often faces challenges of handling rapid request responses and sharing temporary state across multiple requests. The combination of FastAPI (a high-performance asynchronous framework) and Redis (an in-memory database) effectively addresses these issues. FastAPI supports high concurrency, while Redis, with its fast read/write speed and expiration time features, can cache frequently accessed, low-updating data (such as Fibonacci calculation results) to reduce redundant computations and store temporary states (such as user access counters) for cross-request sharing. This article introduces environment setup (installing FastAPI, Redis client, and starting Redis), basic connections (using utility functions to manage Redis clients with `decode_responses=True` to ensure string results), and demonstrates applications through two examples: caching (Fibonacci calculation results) and state management (user access counts). It also mentions dependency injection for code optimization and notes on Redis persistence, connection pooling, and key naming conventions in production environments.