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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。 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 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# 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# 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# 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# 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# 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# 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# 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# 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# 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 导入 Pathfrom fastapi import FastAPI, Path, Query
from typing_extensions import Annotated
声明元数据@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<!DOCTYPE html>
<html lang='en'>
<head>
<meta charset='UTF-8'>
</head>
<body>
<form method='post' action='http://127.0.0.1:8000/login'>
<span>账号：</span><input type='text' name='username'>
<br>
<span>密码：</span><input type='password' name='password'>
<br>
<input type='submit' value='登录'>
</form>
</body>
</html>
FastAPIfrom 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 = '''<body>
<form action='/uploadfile/' enctype='multipart/form-data' method='post'>
<input name='file' type='file' multiple>
<input type='submit'>
</form>
</body>'''
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 |
依赖项依赖项使用场景· 共享业务逻辑（复用相同的代码逻辑） · 共享数据库连接 · 实现安全、验证、角色权限 · 等……
创建依赖项from typing import Union
from fastapi import Depends, FastAPI
app = FastAPI()
# read_items和read_users方法依赖common_parameters
# 白话就是read_items和read_users都需要q，skip，limit查询参数
async def common_parameters(
q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
return {'q': q, 'skip': skip, 'limit': limit}
@app.get('/items/')
async def read_items(commons: dict = Depends(common_parameters)):
return commons
@app.get('/users/')
async def read_users(commons: dict = Depends(common_parameters)):
return commons
类作为依赖项from typing import Union
from fastapi import Depends, FastAPI
app = FastAPI()
fake_items_db = [{'item_name': 'Foo'}, {'item_name': 'Bar'}, {'item_name': 'Baz'}]
class CommonQueryParams:
def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
self.q = q
self.skip = skip
self.limit = limit
# read_itemsx接收一个commons参数，类型是CommonQueryParams
# CommonQueryParams接收三个参数，这三个参数是调用api的时候传
@app.get('/items/')
async def read_items(commons: CommonQueryParams = Depends(CommonQueryParams)):
response = {}
if commons.q:
response.update({'q': commons.q})
items = fake_items_db[commons.skip : commons.skip + commons.limit]
response.update({'items': items})
return response
还可以简写@app.get('/items/')
async def read_items(commons: CommonQueryParams = Depends()): # 这里的Depends没有传参，FastAPI会自动使用CommonQueryParams
response = {}
if commons.q:
response.update({'q': commons.q})
items = fake_items_db[commons.skip : commons.skip + commons.limit]
response.update({'items': items})
return response
子依赖项from typing import Union
from fastapi import Cookie, Depends, FastAPI
app = FastAPI()
def query_extractor(q: Union[str, None] = None):
return q
def query_or_cookie_extractor(
q: str = Depends(query_extractor),
last_query: Union[str, None] = Cookie(default=None),
):
if not q:
return last_query
return q
# read_query函数依赖query_or_cookie_extractor函数
# query_or_cookie_extractor函数又依赖query_extractor函数
# 就是说依赖项可以依赖其他依赖项，只要你不晕，可以无数次套娃
@app.get('/items/')
async def read_query(query_or_default: str = Depends(query_or_cookie_extractor)):
return {'q_or_cookie': query_or_default}
不使用缓存# 使用use_cache = False参数不使用缓存数据
# 不使用use_cache = False,value和value1是一样的
def result_value():
value = randint(1, 99)
return value
def get_value(value: int = Depends(result_value, use_cache=False), value1: int = Depends(result_value, use_cache=False)):
return value, value1
@app.get('/value/')
async def needy_dependency(value: tuple = Depends(get_value)):
return {'value': value}
全局依赖项from fastapi import Depends, FastAPI, Header, HTTPException
async def verify_token(x_token: str = Header()):
if x_token != 'fake-super-secret-token':
raise HTTPException(status_code=400, detail='X-Token header invalid')
async def verify_key(x_key: str = Header()):
if x_key != 'fake-super-secret-key':
raise HTTPException(status_code=400, detail='X-Key header invalid')
return x_key
# 全局依赖项很有用，后面的安全性就可以使用全局依赖项
app = FastAPI(dependencies=[Depends(verify_token), Depends(verify_key)])
@app.get('/items/')
async def read_items():
return [{'item': 'Portal Gun'}, {'item': 'Plumbus'}]
@app.get('/users/')
async def read_users():
return [{'username': 'Rick'}, {'username': 'Morty'}]
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