326 lines
8.0 KiB
Markdown
326 lines
8.0 KiB
Markdown
FastAPI 备忘清单
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===
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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`
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入门
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---
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<!--rehype:body-class=cols-1-->
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### 最小程序
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下面代码会直接启动http服务，也可以使用 `uvicorn main:app --reload`
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```python
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from fastapi import FastAPI
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import uvicorn
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app = FastAPI()
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# http://127.0.0.1:8000/
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@app.get("/")
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async def root():
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return {"message": "Hello World"}
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if __name__ == '__main__':
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uvicorn.run(app='main:app', reload=True)
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```
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### 路径参数
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#### 最基本的路径参数
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```python
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# http://127.0.0.1:8000/items/1
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@app.get("/items/{item_id}")
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async def read_item(item_id):
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return {"item_id": item_id} # item_id自定义
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```
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#### 多个路径参数
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```python
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# http://127.0.0.1:8000/items/1/2
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@app.get("/items/{item_id}/{user_id}")
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async def read_item(item_id, user_id):
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return {"item_id": item_id, "user_id": user_id}
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```
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#### 有类型的路径参数
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```python
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# http://127.0.0.1:8000/items/1
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@app.get("/items/{item_id}")
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async def read_item(item_id: int):
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return {"item_id": item_id}
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```
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#### 文件路径参数
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```python
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# http://127.0.0.1:8000/file//home/my/my.txt
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@app.get("/file/{file_path:path}")
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async def read_item(file_path):
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return {"file_path": file_path}
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```
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### 查询参数
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#### 带默认值的查询参数
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```python
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# http://127.0.0.1:8000/items/?skip=0&limit=2
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fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]
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@app.get("/items/")
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async def read_item(skip: int = 0, limit: int = 10):
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return fake_items_db[skip: skip + limit]
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```
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#### 可选查询参数
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```python
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# http://127.0.0.1:8000/items/1?q=admin
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from typing import Union
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@app.get("/items/{item_id}")
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async def read_item(item_id: str, q: Union[str, None] = None):
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if q:
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return {"item_id": item_id, "q": q}
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return {"item_id": item_id}
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```
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#### 多路径多查询参数
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```python
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# http://127.0.0.1:8000/users/1/items/2
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# or
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# http://127.0.0.1:8000/users/1/items/2?q=query&short=true
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@app.get("/users/{user_id}/items/{item_id}")
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async def read_user_item(
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user_id: int, item_id: str, q: Union[str, None] = None, short: bool = False
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):
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item = {"item_id": item_id, "owner_id": user_id}
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if q:
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item.update({"q": q})
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if not short:
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item.update(
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{"description": "This is an amazing item that has a long description"}
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)
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return item
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```
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#### 必需查询参数
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```python
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# http://127.0.0.1:8000/items/123?needy=yes
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@app.get("/items/{item_id}")
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async def read_user_item(item_id: str, needy: str):
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item = {"item_id": item_id, "needy": needy}
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return item
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```
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### 请求体
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```python
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from pydantic import BaseModel
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from typing import Union
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class Item(BaseModel):
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name: str = '小明'
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description: Union[str, None] = None
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price: float
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tax: Union[float, None] = None
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@app.post("/items/")
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async def create_item(item: Item):
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print(item.name)
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return item
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```
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#### 调用
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```bash
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curl -X 'POST' \
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'http://127.0.0.1:8000/items/' \
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-H 'accept: application/json' \
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-H 'Content-Type: application/json' \
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-d '{
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"name": "小明",
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"description": "string",
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"price": 0,
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"tax": 0
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}'
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```
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### 查询参数和字符串校验
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```python
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from fastapi import Query
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@app.get("/items/")
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async def read_items(q: Union[str, None] = Query(default=None, max_length=50)):
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results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
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if q:
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results.update({"q": q})
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return results
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```
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#### 参数列表
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| 参数 | 含义 | 类型 |
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| ---------- | ------------ | ------------- |
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| default | 默认值 | 任意类型或... |
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| max_length | 最大长度 | int |
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| min_length | 最小长度 | int |
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| pattern | 正则匹配 | string |
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| alias | 别名参数 | string |
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| deprecated | 准备弃用参数 | bool |
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#### 多个相同的查询参数
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```python
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# http://127.0.0.1:8000/items/?q=foo&q=bar
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@app.get("/items/")
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async def read_items(q: Union[List[str], None] = Query(default=None)):
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query_items = {"q": q}
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return query_items
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```
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### 路径参数和数值校验
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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/)
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#### 导入 Path
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```python
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from fastapi import FastAPI, Path, Query
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from typing_extensions import Annotated
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```
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#### 声明元数据
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```python
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@app.get("/items/{item_id}")
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async def read_items(
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item_id: Annotated[int, Path(title="The ID of the item to get")],
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q: Annotated[Union[str, None], Query(alias="item-query")] = None,
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):
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results = {"item_id": item_id}
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if q:
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results.update({"q": q})
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return results
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```
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#### 参数列表
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| 参数 | 含义 | 类型 |
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| ----- | ------------------- | --------- |
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| ... | 和Query具有相同参数 | ... |
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| ge | 大于等于 | int float |
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| gt | 大于 | int float |
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| le | 小于等于 | int float |
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| le | 小于等于 | int float |
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| title | api文档的标题 | string |
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### 其他参数
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都具有Query的参数，max_length、min_length等
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#### Cookie参数
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```python
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from fastapi import Cookie
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@app.get("/items/")
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async def read_items(ads_id: Annotated[Union[str, None], Cookie()] = None):
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return {"ads_id": ads_id}
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```
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#### Header 参数
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```python
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from fastapi import Header
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@app.get("/items/")
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async def read_items(user_agent: Annotated[Union[str, None], Header()] = None,items_id: Annotated[Union[int, None], Header(ge=1)] = None):
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return {"User-Agent": user_agent, "items_id": items_id}
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```
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### 表单数据
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接收的不是 JSON，而是表单字段时，要使用 Form。
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#### 安装
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`pip install python-multipart`
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#### HTML
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```html
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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</head>
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<body>
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<form method="post" action="http://127.0.0.1:8000/login">
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<span>账号：</span><input type="text" name="username">
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<br>
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<span>密码：</span><input type="password" name="password">
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<br>
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<input type="submit" value="登录">
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</form>
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</body>
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</html>
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```
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#### FastAPI
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```python
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from fastapi import FastAPI, Form
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import uvicorn
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app = FastAPI()
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@app.post("/login/")
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async def login(username: str = Form(), password: str = Form()):
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return {"username": username}
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if __name__ == '__main__':
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uvicorn.run(app='main:app', reload=True)
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```
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### 文件上传
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```python
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from fastapi import FastAPI, UploadFile
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from fastapi.responses import HTMLResponse
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@app.post("/uploadfile/")
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async def create_upload_file(file: UploadFile):
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print(file.file.read().decode())
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return {"filenames": file.filename, "type": str(type(file.file))}
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@app.get("/")
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async def main():
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content = """<body>
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<form action="/uploadfile/" enctype="multipart/form-data" method="post">
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<input name="file" type="file" multiple>
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<input type="submit">
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</form>
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</body>"""
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return HTMLResponse(content=content)
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```
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#### UploadFile属性
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| 属性名 | 含义 | 返回 |
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| ------------ | -------- | --------------------------------------- |
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| filename | 文件名 | 上传的文件名 |
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| content_type | 内容类型 | MIME 类型 |
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| file | 文件 | SpooledTemporaryFile具有read，write方法 |
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#### UploadFile async方法
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| 方法名 | 含义 |
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| ------------ | ----------------------------------------- |
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| write(data) | 把 `data` 写入文件 |
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| read(size) | 按指定数量的字节读取文件内容 |
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| seek(offset) | 移动至文件 `offset` （`int`）字节处的位置 |
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| close() | 关闭文件 |
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参考
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---
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- [Python 备忘清单](./python.md) _(jaywcjlove.github.io)_
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- [FastAPI 官方文档](https://fastapi.tiangolo.com/zh/tutorial/) _(fastapi.tiangolo.com)_
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