Fastapi: [QUESTION]Post UploadFile with extra parameter

[PaulSka]

Description

I try do post some extra data with a UploadFile, how it's possible ?
FastApi return Error: Unprocessable Entity

Example :

class MetadataInfoAdd(BaseModel):
    """
        Metadata Info Add Model
    """
    document: str

class MetadataInfo(BaseModel):
    """
        Metadata Info Model
    """
    metadata_key: str
    metadata_value: str
    metadata_type: str

@app.post("/metadata/add", tags=["stable"], response_model=MetadataInfoAdd)
async def metadata_add(metadata: List[MetadataInfo], file: UploadFile = File(...)):
    """
        Perform POST metadata add
    """
    return {"document" : "STR"}

Return this

I change my async def (remove file parameter) like this :

@app.post("/metadata/add", tags=["stable"], response_model=MetadataInfoAdd)
async def metadata_add(metadata: List[MetadataInfo]):
    """
        Perform POST metadata add
    """
    return {"document" : "STR"}

It's work

Is it possible to do this ?

[tiangolo]

It's a limitation of HTTP itself. To upload files the client sends the body payload encoded with "form data".

Any additional data can only be sent using form data, so, simple fields.

It's documented here in a warning: https://fastapi.tiangolo.com/tutorial/request-forms-and-files/#define-file-and-form-parameters

[PaulSka]

Ok thanks for reply :)