Bug: Unable to download files on mongoengine

[eneakllomollari]

Describe the bug
When uploading files or images using mongoengine, it's unable to view due to the incorrect type being passed to StreamingResponse

To Reproduce

• Create an object with a FileField/ImageField
• Attempt to view the file you just uploaded. The thumbnail and download functionality don't work

Environment (please complete the following information):

• starlette-admin==0.10.0
• mongoengine==0.27.0
• Python 3.7.16

Additional context

Traceback (most recent call last):
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/uvicorn/protocols/http/httptools_impl.py", line 405, in run_asgi
    self.scope, self.receive, self.send
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/uvicorn/middleware/proxy_headers.py", line 78, in __call__
    return await self.app(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/fastapi/applications.py", line 270, in __call__
    await super().__call__(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/applications.py", line 124, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/errors.py", line 184, in __call__
    raise exc
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/exceptions.py", line 75, in __call__
    raise exc
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/exceptions.py", line 64, in __call__
    await self.app(scope, receive, sender)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/fastapi/middleware/asyncexitstack.py", line 21, in __call__
    raise e
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/fastapi/middleware/asyncexitstack.py", line 18, in __call__
    await self.app(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/routing.py", line 680, in __call__
    await route.handle(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/routing.py", line 427, in handle
    await self.app(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/applications.py", line 124, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/errors.py", line 184, in __call__
    raise exc
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/exceptions.py", line 75, in __call__
    raise exc
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/middleware/exceptions.py", line 64, in __call__
    await self.app(scope, receive, sender)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/routing.py", line 680, in __call__
    await route.handle(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/routing.py", line 275, in handle
    await self.app(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/routing.py", line 68, in app
    await response(scope, receive, send)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/responses.py", line 273, in __call__
    await wrap(partial(self.listen_for_disconnect, receive))
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 662, in __aexit__
    raise exceptions[0]
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 702, in _run_wrapped_task
    await coro
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/responses.py", line 269, in wrap
    await func()
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/responses.py", line 258, in stream_response
    async for chunk in self.body_iterator:
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/concurrency.py", line 63, in iterate_in_threadpool
    yield await anyio.to_thread.run_sync(_next, iterator)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/anyio/to_thread.py", line 32, in run_sync
    func, *args, cancellable=cancellable, limiter=limiter
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 937, in run_sync_in_worker_thread
    return await future
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 867, in run
    result = context.run(func, *args)
  File "/Users/enea/lean_mail/backend/venv/lib/python3.7/site-packages/starlette/concurrency.py", line 53, in _next
    return next(iterator)
TypeError: 'GridOut' object is not an iterator

[jowilf]

I'm unable to reproduce your issue, It may be linked to the Starlette/FastAPi version you're using. Can you try with the latest version of starlette ?

[eneakllomollari]

Tried with starlette==0.20.4 and seems to be fixed. Thank you!