🐛(s3/backend) Doc content is not saved to s3 | XAmzContentSHA256Mismatch

[jco-c]

Bug Report

Problematic behavior
Document content is not saved. When creating a document and adding content and then switching document, the document still exists but the content is gone.

The logs show repeatedly a XAmzContentSHA256Mismatch error when the backend tries to use _saveobj.upload_fileobj(content, ExtraArgs=params, Config=self.transfer_config) and subsequent calls (not familiar with the backend code). Error message is shown below.

Expected behavior/code
That the document content is saved.

Steps to Reproduce

1. Open a new document
2. Add content
3. Switch to another doc and back
4. Content is gone.

Environment

• Docs version: 3.4.2
• Instance url: docs.lielacloud.org
• s3 backend: Ionos (german hoster for object storage & more)

Possible Solution

Additional context/Screenshots
Error message:

Error Message in Logs

backend-1 | 2025-07-20 10:29:13,441 request.summary ERROR An error occurred (XAmzContentSHA256Mismatch) when calling the PutObject operation: None
backend-1 | 2025-07-20 10:29:13,442 django.request ERROR Internal Server Error: /api/v1.0/documents/3fa9ad28-c31c-4d34-98af-d353628a7b28/
backend-1 | Traceback (most recent call last):
backend-1 | File "/usr/local/lib/python3.13/site-packages/django/core/handlers/exception.py", line 55, in inner
backend-1 | response = get_response(request)
backend-1 | File "/usr/local/lib/python3.13/site-packages/django/core/handlers/base.py", line 197, in _get_response
backend-1 | response = wrapped_callback(request, *callback_args, **callback_kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/django/views/decorators/csrf.py", line 65, in _view_wrapper
backend-1 | return view_func(request, *args, **kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/viewsets.py", line 125, in view
backend-1 | return self.dispatch(request, *args, **kwargs)
backend-1 | ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/views.py", line 515, in dispatch
backend-1 | response = self.handle_exception(exc)
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/views.py", line 475, in handle_exception
backend-1 | self.raise_uncaught_exception(exc)
backend-1 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/views.py", line 486, in raise_uncaught_exception
backend-1 | raise exc
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/views.py", line 512, in dispatch
backend-1 | response = handler(request, *args, **kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/mixins.py", line 82, in partial_update
backend-1 | return self.update(request, *args, **kwargs)
backend-1 | ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/mixins.py", line 68, in update
backend-1 | self.perform_update(serializer)
backend-1 | ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
backend-1 | File "/app/core/api/viewsets.py", line 567, in perform_update
backend-1 | return super().perform_update(serializer)
backend-1 | ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/mixins.py", line 78, in perform_update
backend-1 | serializer.save()
backend-1 | ~~~~~~~~~~~~~~~^^
backend-1 | File "/app/core/api/serializers.py", line 291, in save
backend-1 | return super().save(**kwargs)
backend-1 | ~~~~~~~~~~~~^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/serializers.py", line 205, in save
backend-1 | self.instance = self.update(self.instance, validated_data)
backend-1 | ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/rest_framework/serializers.py", line 1035, in update
backend-1 | instance.save()
backend-1 | ~~~~~~~~~~~~~^^
backend-1 | File "/app/core/models.py", line 467, in save
backend-1 | default_storage.save(file_key, content_file)
backend-1 | ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/django/core/files/storage/base.py", line 49, in save
backend-1 | name = self._save(name, content)
backend-1 | File "/usr/local/lib/python3.13/site-packages/storages/backends/s3.py", line 565, in _save
backend-1 | obj.upload_fileobj(content, ExtraArgs=params, Config=self.transfer_config)
backend-1 | ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/boto3/s3/inject.py", line 764, in object_upload_fileobj
backend-1 | return self.meta.client.upload_fileobj(
backend-1 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
backend-1 | Fileobj=Fileobj,
backend-1 | ^^^^^^^^^^^^^^^^
backend-1 | ...<4 lines>...
backend-1 | Config=Config,
backend-1 | ^^^^^^^^^^^^^^
backend-1 | )
backend-1 | ^
backend-1 | File "/usr/local/lib/python3.13/site-packages/botocore/context.py", line 123, in wrapper
backend-1 | return func(*args, **kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/boto3/s3/inject.py", line 675, in upload_fileobj
backend-1 | return future.result()
backend-1 | ~~~~~~~~~~~~~^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/s3transfer/futures.py", line 111, in result
backend-1 | return self._coordinator.result()
backend-1 | ~~~~~~~~~~~~~~~~~~~~~~~~^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/s3transfer/futures.py", line 287, in result
backend-1 | raise self._exception
backend-1 | File "/usr/local/lib/python3.13/site-packages/s3transfer/tasks.py", line 142, in call
backend-1 | return self._execute_main(kwargs)
backend-1 | ~~~~~~~~~~~~~~~~~~^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/s3transfer/tasks.py", line 165, in _execute_main
backend-1 | return_value = self._main(**kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/s3transfer/upload.py", line 796, in _main
backend-1 | client.put_object(Bucket=bucket, Key=key, Body=body, **extra_args)
backend-1 | ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/botocore/client.py", line 601, in _api_call
backend-1 | return self._make_api_call(operation_name, kwargs)
backend-1 | ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
backend-1 | File "/usr/local/lib/python3.13/site-packages/botocore/context.py", line 123, in wrapper
backend-1 | return func(*args, **kwargs)
backend-1 | File "/usr/local/lib/python3.13/site-packages/botocore/client.py", line 1074, in _make_api_call
backend-1 | raise error_class(parsed_response, operation_name)
backend-1 | botocore.exceptions.ClientError: An error occurred (XAmzContentSHA256Mismatch) when calling the PutObject operation: None

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[jco-c]

I've done some more research and it seems to be an issue with my s3 backend, as it doesn't support the new PutObject operation introduced in boto3 1.36.0. This issue is described here: https://docs.ionos.com/cloud/storage-and-backup/ionos-object-storage/s3-tools/boto3-python-sdk

This can be fixed by adding the following env variables to the docker compose backend environment:

• AWS_REQUEST_CHECKSUM_CALCULATION=when_required
• AWS_RESPONSE_CHECKSUM_VALIDATION=when_required

If you want I can create a pull request to add that hint to the installation docs - does only make sense though, if this issue is not unique to my s3 provider, right?
Let me know what you think :)