Writing to S3 with server-side encryption doesn't work anymore

Problem description

Earlier versions of smart_open (I’ve tested v1.11.1 and v3.0.0) allowed writing to S3 with server-side encryption like this:

output_handle = smart_open.open(out_url, "w", transport_params={         'multipart_upload_kwargs': {             'ServerSideEncryption': 'AES256'         }})

In the latest versions this doesn’t work and I cannot find any documentation or figure out a different way of making it work. The result is I get an error like ValueError: the bucket 'myBucket' does not exist, or is forbidden for access (ClientError('An error occurred (AccessDenied) when calling the CreateMultipartUpload operation: Access Denied'))

Steps/code to reproduce the problem

• install the latest version of smart_open
• create an output handle as shown above

Versions

Please provide the output of:

import platform, sys, smart_open
print(platform.platform())
print("Python", sys.version)
print("smart_open", smart_open.__version__)

Linux-4.4.0-17763-Microsoft-x86_64-with-glibc2.10 Python 3.8.2 (default, Mar 26 2020, 15:53:00) [GCC 7.3.0] smart_open 5.0.0

Checklist

Before you create the issue, please make sure you have:

• Described the problem clearly
• Provided a minimal reproducible example, including any required data
• Provided the version numbers of the relevant software

[mpenkov]

Try this:

client_kwargs = {
  'S3.Client.create_multipart_upload': {
    'ServerSideEncryption': 'AES256',
  }
}
writer = smart_open.open(url, 'w', transport_params={'client_kwargs': client_kwargs})

[challisd]

Sadly no, my old WSL environment got deleted with the last Windows 10 upgrade (thanks Microsoft!)