Empty body schema when adding file upload ability to endpoint

[psowa001]

I am developing endpoint on which users will be able to create articles.
In the body there will be information like description, body, title, etc.
It was working perfectly but when I added ability to add image to article in swagger there is empty request body schema for article, like on below image.

Code:

# ARTICLE
class ArticleBase(BaseModel):
    title: str
    description: str
    content: str
    date_time: datetime
    public: bool

class ArticleCreate(ArticleBase):
    pass

class Article(ArticleBase):
    id: int
    image: str
    author_id: int

@router.post("/articles/")
async def create_user_article(article: ArticleCreate, image: Optional[bytes] = File(None), token: schemas.TokenData = Depends(utils.check_token)):
    return await crud.create_user_article(user_id=token.user_id, article=article)

Any ideas?

[falkben]

what is schemas?

[krishnardt]

The pydantic schemas you might be using is not correct.. and also there is an issue in the functional parameters i.e., usage of image.

[psowa001]

Hi @falkben and @krishnardt, thank you for your answers. Please look at my first post again, I updated it.
@krishnardt could you please indicate there is the issue in my code?
Everything is displaying correctly when remove

image: Optional[bytes] = File(None)

I want uploading image to be optional.

[cmflynn]

I believe this is why(https://fastapi.tiangolo.com/tutorial/request-files/):

You can declare multiple File and Form parameters in a path operation, but you can't also declare Body fields that you expect to receive as JSON, as the request will have the body encoded using multipart/form-data instead of application/json.

This is not a limitation of FastAPI, it's part of the HTTP protocol.

[krishnardt]

Can you try replacing image with the following code....

File(None) --> File(...)

[juntatalor]

I think that it is not possible to use json body and file (image) upload in one handler. Because json is parsed as the whole request body (application/json) and file upload is implemented via multipart/formdata (also whole request body in different format)

I can suggest three possible solutions:

1. Use different handler to attach images (prefered)
2. Use a str field in ArticleCreate model and pass image with base64 encoding
3. Use multipart/formdata for the whole request (article data + files: https://fastapi.tiangolo.com/tutorial/request-forms-and-files/)

[dotX12]

@psowa001, @juntatalor
Better to know the answer late than never :)
A small refinement that allows you to disassemble the models correctly.

https://github.com/dotX12/pyfa-converter

from datetime import datetime
from typing import Optional

from fastapi import FastAPI, UploadFile, File, Form
from pydantic import BaseModel, Field

from pyfa_converter import FormDepends, PyFaDepends

app = FastAPI()


class PostContractBodySchema(BaseModel):
    title: str = Field(..., description="Description title")
    date: Optional[datetime] = Field(
        None, description="Example: 2021-12-14T09:56:31.056Z"
    )


@app.post("/form-data-body")
async def example_foo_body_handler(
    data: PostContractBodySchema = FormDepends(PostContractBodySchema),
    # data1: PostContractBodySchema = PyFaDepends( # OR
    #         model= PostContractBodySchema, _type=Form
    #     ),
    document: UploadFile = File(...),
):
    return {"title": data.title, "date": data.date, "file_name": document.filename}