FastAPI 备忘清单 === FastAPI 是一个用于构建 API 的现代、快速（高性能）的 web 框架，使用 Python 3.6+ 并基于标准的 Python 类型提示。Python: `3.9.5` FastAPI: `0.103.1` 入门 --- ### 最小程序 下面代码会直接启动http服务，也可以使用 `uvicorn main:app --reload` ```python from fastapi import FastAPI import uvicorn app = FastAPI() # http://127.0.0.1:8000/ @app.get("/") async def root(): return {"message": "Hello World"} if __name__ == '__main__': uvicorn.run(app='main:app', reload=True) ``` ### 路径参数 #### 最基本的路径参数 ```python # http://127.0.0.1:8000/items/1 @app.get("/items/{item_id}") async def read_item(item_id): return {"item_id": item_id} # item_id自定义 ``` #### 多个路径参数 ```python # http://127.0.0.1:8000/items/1/2 @app.get("/items/{item_id}/{user_id}") async def read_item(item_id, user_id): return {"item_id": item_id, "user_id": user_id} ``` #### 有类型的路径参数 ```python # http://127.0.0.1:8000/items/1 @app.get("/items/{item_id}") async def read_item(item_id: int): return {"item_id": item_id} ``` #### 文件路径参数 ```python # http://127.0.0.1:8000/file//home/my/my.txt @app.get("/file/{file_path:path}") async def read_item(file_path): return {"file_path": file_path} ``` ### 查询参数 #### 带默认值的查询参数 ```python # http://127.0.0.1:8000/items/?skip=0&limit=2 fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}] @app.get("/items/") async def read_item(skip: int = 0, limit: int = 10): return fake_items_db[skip: skip + limit] ``` #### 可选查询参数 ```python # http://127.0.0.1:8000/items/1?q=admin from typing import Union @app.get("/items/{item_id}") async def read_item(item_id: str, q: Union[str, None] = None): if q: return {"item_id": item_id, "q": q} return {"item_id": item_id} ``` #### 多路径多查询参数 ```python # http://127.0.0.1:8000/users/1/items/2 # or # http://127.0.0.1:8000/users/1/items/2?q=query&short=true @app.get("/users/{user_id}/items/{item_id}") async def read_user_item( user_id: int, item_id: str, q: Union[str, None] = None, short: bool = False ): item = {"item_id": item_id, "owner_id": user_id} if q: item.update({"q": q}) if not short: item.update( {"description": "This is an amazing item that has a long description"} ) return item ``` #### 必需查询参数 ```python # http://127.0.0.1:8000/items/123?needy=yes @app.get("/items/{item_id}") async def read_user_item(item_id: str, needy: str): item = {"item_id": item_id, "needy": needy} return item ``` ### 请求体 ```python from pydantic import BaseModel from typing import Union class Item(BaseModel): name: str = '小明' description: Union[str, None] = None price: float tax: Union[float, None] = None @app.post("/items/") async def create_item(item: Item): print(item.name) return item ``` #### 调用 ```bash curl -X 'POST' \ 'http://127.0.0.1:8000/items/' \ -H 'accept: application/json' \ -H 'Content-Type: application/json' \ -d '{ "name": "小明", "description": "string", "price": 0, "tax": 0 }' ``` ### 查询参数和字符串校验 ```python from fastapi import Query @app.get("/items/") async def read_items(q: Union[str, None] = Query(default=None, max_length=50)): results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]} if q: results.update({"q": q}) return results ``` #### 参数列表 | 参数 | 含义 | 类型 | | ---------- | ------------ | ------------- | | default | 默认值 | 任意类型或... | | max_length | 最大长度 | int | | min_length | 最小长度 | int | | pattern | 正则匹配 | string | | alias | 别名参数 | string | | deprecated | 准备弃用参数 | bool | #### 多个相同的查询参数 ```python # http://127.0.0.1:8000/items/?q=foo&q=bar @app.get("/items/") async def read_items(q: Union[List[str], None] = Query(default=None)): query_items = {"q": q} return query_items ``` ### 路径参数和数值校验 Path用法基本和Query相同，参考：[FastAPI官方文档](https://fastapi.tiangolo.com/zh/tutorial/path-params-numeric-validations/) #### 导入 Path ```python from fastapi import FastAPI, Path, Query from typing_extensions import Annotated ``` #### 声明元数据 ```python @app.get("/items/{item_id}") async def read_items( item_id: Annotated[int, Path(title="The ID of the item to get")], q: Annotated[Union[str, None], Query(alias="item-query")] = None, ): results = {"item_id": item_id} if q: results.update({"q": q}) return results ``` #### 参数列表 | 参数 | 含义 | 类型 | | ----- | ------------------- | --------- | | ... | 和Query具有相同参数 | ... | | ge | 大于等于 | int float | | gt | 大于 | int float | | le | 小于等于 | int float | | le | 小于等于 | int float | | title | api文档的标题 | string | ### 其他参数 都具有Query的参数，max_length、min_length等 #### Cookie参数 ```python from fastapi import Cookie @app.get("/items/") async def read_items(ads_id: Annotated[Union[str, None], Cookie()] = None): return {"ads_id": ads_id} ``` #### Header 参数 ```python from fastapi import Header @app.get("/items/") async def read_items(user_agent: Annotated[Union[str, None], Header()] = None,items_id: Annotated[Union[int, None], Header(ge=1)] = None): return {"User-Agent": user_agent, "items_id": items_id} ``` ### 表单数据 接收的不是 JSON，而是表单字段时，要使用 Form。 #### 安装 `pip install python-multipart` #### HTML ```html
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``` #### FastAPI ```python from fastapi import FastAPI, Form import uvicorn app = FastAPI() @app.post("/login/") async def login(username: str = Form(), password: str = Form()): return {"username": username} if __name__ == '__main__': uvicorn.run(app='main:app', reload=True) ``` ### 文件上传 ```python from fastapi import FastAPI, UploadFile from fastapi.responses import HTMLResponse @app.post("/uploadfile/") async def create_upload_file(file: UploadFile): print(file.file.read().decode()) return {"filenames": file.filename, "type": str(type(file.file))} @app.get("/") async def main(): content = """
""" return HTMLResponse(content=content) ``` #### UploadFile属性 | 属性名 | 含义 | 返回 | | ------------ | -------- | --------------------------------------- | | filename | 文件名 | 上传的文件名 | | content_type | 内容类型 | MIME 类型 | | file | 文件 | SpooledTemporaryFile具有read，write方法 | #### UploadFile async方法 | 方法名 | 含义 | | ------------ | ----------------------------------------- | | write(data) | 把 `data` 写入文件 | | read(size) | 按指定数量的字节读取文件内容 | | seek(offset) | 移动至文件 `offset` （`int`）字节处的位置 | | close() | 关闭文件 | 参考 --- - [Python 备忘清单](./python.md) _(jaywcjlove.github.io)_ - [FastAPI 官方文档](https://fastapi.tiangolo.com/zh/tutorial/) _(fastapi.tiangolo.com)_