fastapi: Not rendering multi-select in API doc while using Pydantic model

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Example Code

import typing
from fastapi import FastAPI, Query, Depends
from pydantic import BaseModel
from enum import Enum

app = FastAPI()


class Status(str, Enum):
    SUCCESS = "SUCCESS"
    REFUND = "REFUND"
    FAIL = "FAIL"
    CANCEL = "CANCEL"


@app.get("/working-example/")
async def root_with_normal_query_params(status_in: typing.List[Status] = Query(...)):
    return {"status_inputs": status_in}


class StatusModel(BaseModel):
    status_in: typing.List[Status]


@app.get("/not-working-example/")
async def root_with_pydantic(status_inputs: StatusModel = Depends()):
    return {"status_inputs": status_inputs}

Description

The API docs are not generating the multi-select option while using the Pydantic model for the query/request parser.

without using Pydantic model

with using Pydantic model

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.70.1

Python Version

Python 3.9.11

Additional Context

No response

About this issue

Original URL
State: closed
Created 2 years ago
Comments: 16 (8 by maintainers)

Most upvoted comments

You can use dataclass from Pydantic.

import typing
from enum import Enum

from fastapi import FastAPI, Query, Depends
from pydantic.dataclasses import dataclass

app = FastAPI()


class Status(str, Enum):
    SUCCESS = "SUCCESS"
    REFUND = "REFUND"
    FAIL = "FAIL"
    CANCEL = "CANCEL"


@app.get("/working-example/")
async def root_with_normal_query_params(status_in: typing.List[Status] = Query(...)):
    return {"status_inputs": status_in}


@dataclass
class StatusModel:
    status_in: list[Status] = Query(...)


@app.get("/not-working-example/")  # it now works
async def root_with_pydantic(status_inputs: StatusModel = Depends()):
    return {"status_inputs": status_inputs}

iudeen on Jul 20, 2022