File upload with additional form-data results in UnprocessableEntity[422]

[raghav-knowbe4]

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Example Code

from fastapi import FastAPI, File, Form, UploadFile

app = FastAPI()

@app.post("/upload")
async def upload_files(file: UploadFile = File(...), context: str = Form(...)):
    return {"hello": "world"}

Description

I am able to access the file with the following implementation:

@app.post("/upload")
async def upload_files(file: UploadFile = File(...)):
    print(file.filename) # this works
    return {"hello": "world"}

However, when I send additional form-data along with the file, there are two cases:

@app.post("/upload")
async def upload_files(file: UploadFile = File(...), context: str = Form(...)):
    return {"hello": "world"}

With "Content-Length" in headers, I get following error:

Did not find boundary character 99 at index 2

Without "Content-Length" in headers, I get UnprocessableEntity[422] with following response:

{
    "detail": [
        {
            "type": "missing",
            "loc": [
                "body",
                "context"
            ],
            "msg": "Field required",
            "input": null,
            "url": "https://errors.pydantic.dev/2.5/v/missing"
        },
        {
            "type": "missing",
            "loc": [
                "body",
                "file"
            ],
            "msg": "Field required",
            "input": null,
            "url": "https://errors.pydantic.dev/2.5/v/missing"
        }
    ]
}

Operating System

macOS

Operating System Details

No response

FastAPI Version

0.109.0

Pydantic Version

2.5.3

Python Version

3.11

Additional Context

No response

[Kludex]

Can you share the client call you are using, and which client, please?

[YuriiMotov]

Let's close this for now to keep the discussions clean and organized.
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