FastAPI Basic Tutorial: Basic Usage of Routes, Requests, and Responses
FastAPI is a high-performance Python-based web framework with performance comparable to Node.js and Go. It features auto-generated Swagger UI and ReDoc documentation, type hint-based data validation, and concise, easy-to-learn code. Installation requires `pip install fastapi uvicorn` to obtain the framework and ASGI server. Basic routes are defined using the `@app` decorator, supporting path parameters (e.g., `/items/{item_id}`) and query parameters (e.g., `/search?q=test`), with automatic parameter type validation and conversion. Request handling relies on Pydantic models to define JSON request bodies, such as the `Item` class for receiving POST data. Response handling can specify `response_model` to return Pydantic models or use `status_code` to set status codes (e.g., 201). A complete example includes multiple routes and request/response handling. To run it, use `uvicorn main:app --reload`, and access `/docs` or `/redoc` to view the auto-generated API documentation. FastAPI enhances API development efficiency with its simplicity and automatic documentation features, making it suitable for quickly developing high-performance web services.
Read MoreFastAPI Getting Started: Fundamentals of a Web Framework Every Python Developer Should Learn
A Web framework is a tool for rapidly building web applications, encapsulating details such as HTTP handling to allow developers to focus on business logic. FastAPI is a modern Python web framework built on Starlette and Pydantic, characterized by high performance, automatic API documentation generation (Swagger UI/ReDoc), asynchronous support, and data validation. Installation requires `pip install fastapi uvicorn`, and running it uses `uvicorn main:app --reload`. A basic example returns `{"message": "Hello, FastAPI!"}`. It supports path parameters (e.g., `/users/{user_id}`) and query parameters, with Pydantic models for data validation. It handles GET (retrieving data) and POST (submitting data) requests, with form data processed using `Form`. API documentation is auto-generated, accessible via `/docs` or `/redoc` for interactive testing. It supports asynchronous interfaces (`async def`) to handle high concurrency. Ideal for quickly developing RESTful APIs, it is recommended to start with basic examples and gradually learn advanced content such as middleware and dependency injection.
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