How can I user a "private" variable (_var) as a field on models

[Brunux]

Description
I'm using mongoDB an I want to match the internal id of mongo documents _id to a model field, so my model and route looks similar to:

from typing import List

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


@app.get("/items/{_id}", response_model=Item)
async def get_item(_id: str):
    # Getting the item from DB
    item = db.item.find_one({"_id": _id})
    return item

So I have notice that the variable _id is omitted on parsing from the model so not included in this response.

So I was wondering if it is possible to include it somehow?

Checking Pydantic field parsing I found:

https://github.com/samuelcolvin/pydantic/blob/8c0f805d15d6fddca20ec691c6299a92e1ab15c1/pydantic/main.py#L749-L750

So probably is on Pydantic side?

[nkhitrov]

You can use alias from Field.

And yes, it's pydanatic side.

from fastapi import FastAPI
from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str
    id: str = Field(..., alias="_id")


@app.get("/items/{_id}", response_model=Item)
async def get_item(_id: str):
    # Getting the item from DB (fake)
    item = {"_id": _id, "name": "test"}
    return item

[tiangolo]

Yep, what @SlyFoxy said ☝️

Thanks for the help @SlyFoxy ! 👏 🍰

[github-actions[bot]]

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