响应模型

返回与输入相同的模型

永远不要存储用户的明文密码，也不要在响应中发送密码。

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: EmailStr
    full_name: Union[str, None] = None


@app.post("/user/")
async def create_user(user: UserIn) -> UserIn:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345",
    "email": "xxx@163.com"
}

返回信息

{
    "username": "alex",
    "password": "12345",
    "email": "xxx@163.com",
    "full_name": null
}

返回与输入不同的模型

创建一个有明文密码的输入模型和一个没有明文密码的输出模型

你可以在任意的路径操作中使用 response_model 参数来声明用于响应的模型：

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

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()

# 输入
class UserIn(BaseModel):
    username: str
    password: str
    email: EmailStr
    full_name: Union[str, None] = None

# 输出
class UserOut(BaseModel):
    username: str
    email: EmailStr
    full_name: Union[str, None] = None


@app.post("/user/", response_model=UserOut)
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345",
    "email": "xxx@163.com"
}

返回信息

{
    "username": "alex",
    "email": "xxx@163.com",
    "full_name": null
}

过滤字段的默认值

可以设置路径操作装饰器中的response_model_exclude_unset=True参数，然后响应中将不会包含那些默认值，而是仅有实际设置的值

同一个模型

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None


@app.post("/user/", response_model=UserIn, response_model_exclude_unset=True)
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345"
}

返回信息

{
    "username": "alex",
    "password": "12345"
}

不同模型

使用response_model_exclude_unset=True会失效

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None


class UserOut(BaseModel):
    username: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None


@app.post("/user/", response_model=UserOut, response_model_exclude_unset=True)
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345"
}

返回信息

{
    "username": "alex",
    "email": null,
    "full_name": null
}

解决不同模型不过滤默认值

使用response_model_exclude_defaults=True或response_model_exclude_none=True也是可以达到一样的效果的

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None


class UserOut(BaseModel):
    username: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None


@app.post("/user/", response_model=UserOut, response_model_exclude_none=True)
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345"
}

返回信息

{
    "username": "alex"
}

设置返回的字段

这是因为即使使用 response_model_include 或 response_model_exclude 来省略某些属性，在应用程序的 OpenAPI 定义（和文档）中生成的 JSON Schema 仍将是完整的模型,这也适用于作用类似的 response_model_by_alias。

使用 list 或 tuple，FastAPI 仍会将其转换为 set 并且正常工作，如response_model_exclude=[xx,xx]

response_model_exclude不允许字段

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None

# 过滤返回字段password
@app.post("/user/", response_model=UserIn, response_model_exclude={"password"})
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345"
}

返回信息

{
    "username": "alex",
    "email": null,
    "full_name": null
}

response_model_include允许字段

from typing import Any, Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: Union[EmailStr, None] = None
    full_name: Union[str, None] = None

# 只允许返回username和email
@app.post("/user/", response_model=UserIn, response_model_include={"username", "email"})
async def create_user(user: UserIn) -> Any:
    return user

Post请求

http://127.0.0.1:8000/user/

{
    "username": "alex",
    "password": "12345"
}

返回信息

{
    "username": "alex",
    "email": null
}

多个模型