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How about using annotated-types' MaxLen: https://github.com/annotated-types/annotated-types/#minlen-maxlen-len.

Usage would be async def endoint(files: Annotated[list[UploadFile], MaxLen(10)]) which is nicely analogous to async def endpoint(users: Annotated[list[User], MaxLen(10)])

How about using annotated-types' MaxLen: https://github.com/annotated-types/annotated-types/#minlen-maxlen-len.

Usage would be async def endoint(files: Annotated[list[UploadFile], MaxLen(10)]) which is nicely analogous to async def endpoint(users: Annotated[list[User], MaxLen(10)])

@adriangb Interesting! Will take a look at that approach

From what I can see I believe this would be the first usage of the annotated-types library in FastAPI - I would feel hesitant to put forward such a dependency without it being the recommended approach

It’s going to be a dependency anyway via Pydantic V2

It’s going to be a dependency anyway via Pydantic V2

@adriangb Ah great, that's good to know thanks!

Do you know at all if FastAPI will start using them as a common pattern?

Yes it will be, Sebastián is working on but not sure when he’ll be merging the PR with Pydantic V2, but I’m guessing before this PR

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hi @tiangolo @adriangb any updates on this?

Having the ability to do this would be useful for many usecases. Looking forward for updates.

For my specific use case this is pretty important to me. Anyone aware of any workarounds? Any updates on this?

any updates on this

Hi,
I found a workaround on this issue. As pointed on this StackOverflow thread

Basically, you need to set the max_fields & max_files in request.form on Starlette's Request object as below :

Set max files / max fields

async def get_body(request: Request):
    try:
        ## adjust max_fields & max_files based on your needs
        return await request.form(max_fields=1000000, max_files=100000)
    except Exception as exc:
        raise HTTPException(status_code=400, detail='Invalid Form data') from exc

then on your route, use above function as Depend on body

@app.post("/send-files")
async def send_files(body = Depends(get_body)):
    ## get your files using getlist('<files field name>')
    if isinstance(body, FormData):
        files = body.getlist('files')

    ## 'files' variable will be instance of List[UploadFile]
    ....process your files here
    
    return {
        'totalFiles': len(files)
    }

Hope this helps

Hi, I found a workaround on this issue. As pointed on this StackOverflow thread

Basically, you need to set the max_fields & max_files in request.form on Starlette's Request object as below :

Set max files / max fields

async def get_body(request: Request):
    try:
        ## adjust max_fields & max_files based on your needs
        return await request.form(max_fields=1000000, max_files=100000)
    except Exception as exc:
        raise HTTPException(status_code=400, detail='Invalid Form data') from exc

then on your route, use above function as Depend on body

@app.post("/send-files")
async def send_files(body = Depends(get_body)):
    ## get your files using getlist('<files field name>')
    if isinstance(body, FormData):
        files = body.getlist('files')

    ## 'files' variable will be instance of List[UploadFile]
    ....process your files here
    
    return {
        'totalFiles': len(files)
    }

Hope this helps

Your solution looks to work, but it’s not clear how to combine it with this:

@app.post("/images")
async def upload_images(
   field_0: Annotated[str, Body(...)],
   ...
   field_k: Annotated[str, Body(...)],
   images: Annotated[List[UploadFile], File()]):

without losing the default behavior (pydantic type validations, auto documentation, etc..). So far the only option that comes to mind is: parse the form, create a pydantic model, perform validation, pass the fields directly to the method upload_images.

async def workaround(self, request: Request):
    try:
        form_body = await request.form(max_fields=4, max_files=5000)
        params = AddImagesParams(**{**form_body, 'images': form_body.getlist("images")})
    except ValidationError as ve:
        raise HTTPException(status_code=422, detail=ve.errors())
    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))
    return await self.add_images(task_id=params.task_id, class_name=params.class_name, images=params.images)

But in my mind it looks cumbersome and ugly. Maybe I'm complicating things and there is a more correct and simpler way?