when datetime is null and start_datetime and end_datetime are valid, I get an attribute error

[leotizzei]

Hello everyone,

It seems that stac-fastapi-sqlalchemy does not support STAC items that have "datetime": null, even though it is specified in STAC spec https://github.com/radiantearth/stac-spec/blob/master/item-spec/item-spec.md#properties-object. When I submit a request to the endpoint: POST /collections/hls-agb-preprocessed/bulk_items I get HTTP/1.1" 500 Internal Server Error. Am I doing something wrong? Please let me know if you need any clarification. Thanks!

Please see below a slice of the item file:

    "datetime": null,
    "start_datetime": "2019-05-01T00:00:00Z",
    "end_datetime": "2019-07-31T00:00:00Z"

This is the error message:

INFO:     10.128.20.1:42998 - "POST /collections/hls-agb-preprocessed/bulk_items HTTP/1.1" 500 Internal Server Error
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/uvicorn/protocols/http/httptools_impl.py", line 419, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
  File "/usr/local/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py", line 78, in __call__
    return await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/fastapi/applications.py", line 289, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/applications.py", line 122, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 184, in __call__
    raise exc
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.8/site-packages/stac_fastapi/api/middleware.py", line 75, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/cors.py", line 83, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/brotli_asgi/__init__.py", line 85, in __call__
    await gzip_responder(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/gzip.py", line 44, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/exceptions.py", line 79, in __call__
    raise exc
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/exceptions.py", line 68, in __call__
    await self.app(scope, receive, sender)
  File "/usr/local/lib/python3.8/site-packages/fastapi/middleware/asyncexitstack.py", line 20, in __call__
    raise e
  File "/usr/local/lib/python3.8/site-packages/fastapi/middleware/asyncexitstack.py", line 17, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 718, in __call__
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 276, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 66, in app
    response = await func(request)
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 273, in app
    raw_response = await run_endpoint_function(
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 190, in run_endpoint_function
    return await dependant.call(**values)
  File "/usr/local/lib/python3.8/site-packages/stac_fastapi/api/routes.py", line 68, in _endpoint
    await func(request_data, request=request), response_class
  File "/usr/local/lib/python3.8/site-packages/stac_fastapi/api/routes.py", line 32, in run
    return await run_in_threadpool(func, *args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/starlette/concurrency.py", line 41, in run_in_threadpool
    return await anyio.to_thread.run_sync(func, *args)
  File "/usr/local/lib/python3.8/site-packages/anyio/to_thread.py", line 33, in run_sync
    return await get_asynclib().run_sync_in_worker_thread(
  File "/usr/local/lib/python3.8/site-packages/anyio/_backends/_asyncio.py", line 877, in run_sync_in_worker_thread
    return await future
  File "/usr/local/lib/python3.8/site-packages/anyio/_backends/_asyncio.py", line 807, in run
    result = context.run(func, *args)
  File "/app/stac_fastapi/sqlalchemy/transactions.py", line 193, in bulk_item_insert
    processed_items = [self._preprocess_item(item) for item in items]
  File "/app/stac_fastapi/sqlalchemy/transactions.py", line 193, in <listcomp>
    processed_items = [self._preprocess_item(item) for item in items]
  File "/app/stac_fastapi/sqlalchemy/transactions.py", line 182, in _preprocess_item
    db_model = self.item_serializer.stac_to_db(item)
  File "/app/stac_fastapi/sqlalchemy/serializers.py", line 108, in stac_to_db
    field_value = rfc3339_str_to_datetime(field_value)
  File "/usr/local/lib/python3.8/site-packages/stac_fastapi/types/rfc3339.py", line 30, in rfc3339_str_to_datetime
    s = s.upper()
AttributeError: 'NoneType' object has no attribute 'upper'