Pydantic view helper decorator

Installation

pip install pydantic_view

Usage

In [1]: from uuid import UUID, uuid4
   ...: 
   ...: from pydantic import BaseModel, Field
   ...: from pydantic_view import view
   ...: 
   ...: 
   ...: @view("Create", exclude={"id"})
   ...: @view("Update")
   ...: @view("Patch", optional={"username", "password", "address"})
   ...: @view("Out", exclude={"password"})
   ...: class User(BaseModel):
   ...:     id: int
   ...:     username: str
   ...:     password: str
   ...:     address: str
   ...: 

In [2]: user = User(id=0, username="human", password="iamaman", address="Earth")
   ...: user.Out()
   ...: 
Out[2]: UserOut(id=0, username='human', address='Earth')

In [3]: User.Update(id=0, username="human", password="iamasuperman", address="Earth")
   ...: 
Out[3]: UserUpdate(id=0, username='human', password='iamasuperman', address='Earth')

In [4]: User.Patch(id=0, address="Mars")
   ...: 
Out[4]: UserPatch(id=0, username=None, password=None, address='Mars')

FastAPI example

from typing import List

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel, Field

from pydantic_view import view, view_validator


@view("Out", exclude={"secret"})
@view("Create", exclude={"id"}, config={"extra": "forbid"})
@view("Update", exclude={"id"})
@view("UpdateMany")
@view("Patch", exclude={"id"}, optional={"name", "secret"})
@view("PatchMany", optional={"name", "secret"})
class Group(BaseModel):
    id: int
    name: str
    secret: str = None

    @view_validator(["Create", "Update", "UpdateMany", "Patch", "PatchMany"], "name", allow_reuse=True)
    def validate_name(cls, v):
        if v == "admin":
            raise ValueError("Invalid name")
        return v


@view("Out", exclude={"password"}, recursive=True)
@view(
    "Create",
    exclude={"id"},
    fields={"groups": Field(default_factory=lambda: [Group(id=0, name="default")])},
    config={"extra": "forbid"},
    recursive=True,
)
@view("Update", exclude={"id"}, recursive=True)
@view("UpdateMany", recursive=True)
@view("Patch", exclude={"id"}, optional={"username", "password", "groups"}, recursive=True)
@view("PatchMany", optional={"username", "password", "groups"}, recursive=True)
class User(BaseModel):
    id: int
    username: str
    password: str
    groups: List[Group]


app = FastAPI()

db = {}


@app.get("/users/{user_id}", response_model=User.Out)
async def get(user_id: int) -> User.Out:
    return db[user_id]


@app.post("/users", response_model=User.Out)
async def post(user: User.Create) -> User.Out:
    user_id = 0  # generate_user_id()
    db[0] = User(id=user_id, **user.dict())
    return db[0]


@app.put("/users/{user_id}", response_model=User.Out)
async def put(user_id: int, user: User.Update) -> User.Out:
    db[user_id] = User(id=user_id, **user.dict())
    return db[user_id]


@app.put("/users", response_model=List[User.Out])
async def put_many(users: List[User.UpdateMany]) -> List[User.Out]:
    for user in users:
        db[user.id] = user
    return users


@app.patch("/users/{user_id}", response_model=User.Out)
async def patch(user_id: int, user: User.Patch) -> User.Out:
    db[user_id] = User(**{**db[user_id].dict(), **user.dict(exclude_unset=True)})
    return db[user_id]


@app.patch("/users", response_model=List[User.Out])
async def patch_many(users: List[User.PatchMany]) -> List[User.Out]:
    for user in users:
        db[user.id] = User(**{**db[user.id].dict(), **user.dict(exclude_unset=True)})
    return [db[user.id] for user in users]


def test_fastapi():
    client = TestClient(app)

    # POST
    response = client.post(
        "/users",
        json={
            "username": "admin",
            "password": "admin",
        },
    )
    assert response.status_code == 200
    assert response.json() == {
        "id": 0,
        "username": "admin",
        "groups": [{"id": 0, "name": "default"}],
    }

    # GET
    response = client.get("/users/0")
    assert response.status_code == 200
    assert response.json() == {
        "id": 0,
        "username": "admin",
        "groups": [{"id": 0, "name": "default"}],
    }

    # PUT
    response = client.put(
        "/users/0",
        json={
            "username": "superadmin",
            "password": "superadmin",
            "groups": [],
        },
    )
    assert response.status_code == 200
    assert response.json() == {
        "id": 0,
        "username": "superadmin",
        "groups": [],
    }

    # PUT many
    response = client.put(
        "/users",
        json=[
            {
                "id": 0,
                "username": "admin",
                "password": "admin",
                "groups": [{"id": 0, "name": "default", "secret": "secret_value"}],
            }
        ],
    )
    assert response.status_code == 200
    assert response.json() == [
        {
            "id": 0,
            "username": "admin",
            "groups": [{"id": 0, "name": "default"}],
        }
    ]

    # PATCH
    response = client.patch("/users/0", json={"id": 0, "username": "guest"})
    assert response.status_code == 200
    assert response.json() == {
        "id": 0,
        "username": "guest",
        "groups": [{"id": 0, "name": "default"}],
    }

    # PATCH many
    response = client.patch("/users", json=[{"id": 0, "groups": []}])
    assert response.status_code == 200
    assert response.json() == [
        {
            "id": 0,
            "username": "guest",
            "groups": [],
        }
    ]