python - passing dict value to BaseModel via Postman and OpenAPI in FastAPI

Question

I have frustrated with this problem I googled it and I didn't find a proper answer so decided to ask it here. I have the following classes

from fastapi import FastAPI, File, UploadFile, BackgroundTasks, Body
from pydantic import BaseModel
import shutil
import datetime

class UserIn(BaseModel):
    username: str
    password: str
    family: str
    age: int
    height: float
    gender: bool

usr = UserIn(username='Bob', password='123456', family='Foo', age=21, height=169, gender=True)

and the following route method

@app.post("/uploadfile/")
async def create_upload_file(background_tasks: BackgroundTasks, current_user: UserIn = Body(usr),
                         file: UploadFile = File(...)):
    background_tasks.add_task(send_video_for_process, file, current_user)
    return {"message": f"The {current_user.username} file {file.filename} uploaded"}

and the function is

def send_video_for_process(video: UploadFile, user: UserIn):
    content = video.file
    video_path = '/users/'
    path = video_path + user.username + video.filename
    with open(path, "wb") as buffer:
        shutil.copyfileobj(content, buffer) 
    return 'Done!'

When I don't pass anything the method pass usr correctly, but when I want to pass it with postman or docs of Fastapi. I am getting the following error.

{
"detail": [
    {
        "loc": [
            "body",
            "current_user"
        ],
        "msg": "value is not a valid dict",
        "type": "type_error.dict"
    }
]}

the dictionary I put in postman is this {"username": "Alice","password": "abcd1234","family": "Hey","age": 19,"height": 160,"gender": False}

and here is a screenshot of my postman.

in the /docs I only change the value inside the schema but still get the same error.

I have added all libraries and I tried without Body(...) version. I played a lot with the dictionary but I got nothing. I don't want to use Form or Query. I need the benefit of BaseModel in the future.

I use Mac and my server is uvicorn.

Any idea what is going on?

question from:https://stackoverflow.com/questions/65910629/passing-dict-value-to-basemodel-via-postman-and-openapi-in-fastapi

Answer 1

Two things.

1. The Postman screenshot shows you're using the form-data encoding for the body, which messes up with the path operation function definition which expects a json. You should use 'raw' to send directly json data.

2. You used False with a capital 'F' in the body, which is Python language and not compliant with json (need to write false), which may be the remaining cause of the error for OpenAPI.