Fastapi UploadFile with a payload

[qasimkhan348]

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to FastAPI but to Pydantic.
• I already checked if it is not related to FastAPI but to Swagger UI.
• I already checked if it is not related to FastAPI but to ReDoc.

Commit to Help

• I commit to help with one of those options 👆

Example Code

from fastapi import UploadFile
from typing import Union
    @router.post("/",
                 summary="Store pdf in database",
                 description="Store pdf in database and return pdf",
                 status_code=status.HTTP_201_CREATED,
                 responses={status.HTTP_400_BAD_REQUEST: {"model": ResponseMessage},
                            status.HTTP_401_UNAUTHORIZED: {"model": ResponseMessage},
                            status.HTTP_422_UNPROCESSABLE_ENTITY: {"model": ResponseMessage},
                            status.HTTP_500_INTERNAL_SERVER_ERROR: {"model": ResponseMessage}})
    async def create(self, slip_code: str, payload: PDFPrinting, upload_file: Union[UploadFile, None] = None, upload_file1: Union[UploadFile, None] = None, tax_year: int = TAX_YEAR_VALIDATION_RULE) -> ResponseMessage:

Description

• When I am using fastapi uploadfile to upload pdf file and request payload in query parameter then it gives us 422 error with message("Expected UploadFile, received: <class 'str'>") , I want to upload files and also want to send request payload as I shown in picture request payload. Why it is sending this error shown in error_face picture. please response.
  
  

Operating System

Windows

Operating System Details

window 11

FastAPI Version

fastapi==0.78.0

Python Version

3.9.9

Additional Context

No response

[andersonrocha0]

Hey @qasimkhan348 Take a look at this point in the documentation:

https://fastapi.tiangolo.com/tutorial/request-files/#what-is-form-data

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.

So, to fix this, you could try something like that:

from fastapi import UploadFile, FastAPI, Depends, Form, Query
from typing import Union

from pydantic import BaseModel

app = FastAPI()


class Test(BaseModel):
    asdfg: str
    qwert: str


@app.post("/",
          summary="Store pdf in database",
          description="Store pdf in database and return pdf")
# The payload can't be a json as sad in the FastAPI documentation:
# https://fastapi.tiangolo.com/tutorial/request-files/#what-is-form-data
#
# 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.
async def create(slip_code: str, payload: str = Query(description="Here we need a json ..."),
                 upload_file: Union[UploadFile, None] = None,
                 upload_file1: Union[UploadFile, None] = None,
                 tax_year: int = 10) -> None:
    # In this case, the payload should be a string, and you could convert it to your json and to your object
    # Json example: {"asdfg":"asdfg","qwert":"qwert"}

    test = Test.parse_raw(payload)
    print(test.asdfg)
    print(test.qwert)

I hope this could help you. :)

[qasimkhan348]

@andersonrocha0 Thank You Sir for your time, I appreciate your answer we found also this that HTTP Protocol doesn't support multipart data format in one payload e.g.(form data, request body), You were right in that Side But the Solution that you provide will not work for us because request body are not taking in request payload with form data as shown in above picture. I think if we want to solve this problem then request payload should not be multipart data.
Thanks again.

[agronick]

You need to upload files in the file upload dialogs and remove them from the request payload.