学习资源： FastAPI官方文档

环境配置

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pip install "fastapi[standard]"

First Step

简单示例

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from fastapi import FastAPI
app = FastAPI()

@app.get("/")
async def hello():
    return {"message": "hello world"}
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(agentlearning) PS D:\code\PythonProject> fastapi dev fast_api.py --port 8001  #规定端口号

   FastAPI   Starting development server 🚀
 
             Searching for package file structure from directories with __init__.py files
             Importing from D:\code\PythonProject
 
    module   🐍 fast_api.py
 
      code   Importing the FastAPI app object from the module with the following code:
 
             from fast_api import app
 
       app   Using import string: fast_api:app
 
    server   Server started at http://127.0.0.1:8001
    server   Documentation at http://127.0.0.1:8001/docs
 
       tip   Running in development mode, for production use: fastapi run
 
             Logs:
 
      INFO   Will watch for changes in these directories: ['D:\\code\\PythonProject']
      INFO   Uvicorn running on http://127.0.0.1:8001 (Press CTRL+C to quit)
      INFO   Started reloader process [2252] using WatchFiles
      INFO   Started server process [6800]
      INFO   Waiting for application startup.
      INFO   Application startup complete.
      INFO   127.0.0.1:51683 - "GET / HTTP/1.1" 200
      INFO   127.0.0.1:51683 - "GET /docs HTTP/1.1" 200
      INFO   127.0.0.1:51683 - "GET /openapi.json HTTP/1.1" 200
      INFO   127.0.0.1:53840 - "GET / HTTP/1.1" 200

指定app位置的不同方式

命令行直接指定

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fastapi dev fast_api.py
fastapi dev --entrypoint fast_api:app

可以在 pyproject.toml文件中规定app的位置:

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[tool.fastapi]
entrypoint="fast_api:app"

此时就不用明确指定运行哪个文件:

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fastapi dev

部署

可以把FastAPI app部署到 FastAPI Cloud

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fastapi deploy

常用operatio

  • GET : read
  • PUSH : update
  • DELETE : delete
  • POST : create

创建a path operation decorator

@app.get("/")的作用是告诉FastAPI:

  1. 要处理的路径是"/"
  2. 使用get装饰器

其他类似操作:

  • @app.post()
  • @app.put()
  • @app.delete()

定义path operation function

即如果访问上面创建的路径,应该采取什么动作(执行什么函数)

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from fastapi import FastAPI
app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

如果使用GET访问/路径,会执行root函数,返回"Hello World"字符串

Path Parameters

对于路径可以搭配不同的参数使用

  1. 无参数 
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    @app.get("/")
  2. 定义变量 
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    @app.get("/item/{item_id}")
    async def get_item(item_id:str):
        return {"item_id":item_id}
    item_id这个变量会通过路径传给函数