• path operations에서 response_model 을 통해 model을 선언할 수 있다.
  • path operations : @app.get(), @app.post(), etc ...

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: list[str] = []


@app.post("/items/", response_model=Item)
async def create_item(item: Item):
    return item

• type 선언 대로 출력 데이터를 변환해준다.
• data를 검증한다.
• JSON schema에 reponse를 추가한다.
• 문서 자동화

Return the same input data

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


# Don't do this in production!
@app.post("/user/", response_model=UserIn)
async def create_user(user: UserIn):
    return user

Add an output model

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


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):
    return user

• passward는 보내면 안되니까 이렇게 해보는 예시를 보여준다.
• path operation function이 같은 녀석을 return 하지만 passward는 포함하지 않도록 제한할 수 있는 것이다.
  • Filtering 개념

Response Model encoding parameters

from typing import List, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: List[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}


@app.get("/items/{item_id}", response_model=Item, response_model_exclude_unset=True)
async def read_item(item_id: str):
    return items[item_id]

• response model은 default 값을 가질 수도 있다.

Use the reponse_model_exclude_unset parameter

from typing import List, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: List[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}


@app.get("/items/{item_id}", response_model=Item, response_model_exclude_unset=True)
async def read_item(item_id: str):
    return items[item_id]

• default 값들이 response에 포함되지 않도록 하는 설정이다.

{
    "name": "Foo",
    "price": 50.2
}

@app.get(
    "/items/{item_id}/name",
    response_model=Item,
    response_model_include={"name", "description"},
)
async def read_item_name(item_id: str):
    return items[item_id]


@app.get("/items/{item_id}/public", response_model=Item, response_model_exclude={"tax"})
async def read_item_public_data(item_id: str):
    return items[item_id]

• 또한, 다양한 설정들이 있다. response_model_exclude, response_model_include
• 포함할 속성들의 이름을 string set으로 설정해주면 된다.
  • list로도 설정 가능