[Python] lambda function fails to process tarball

What specific code needs to be changed below in order for a python 3 lambda function to successfully decode a tar file that was sent to it from a remote python3 application which sends an API Post request routed into the lambda function?

ERROR MESSAGE:

A ValueError: string argument should contain only ASCII characters message is thrown by the line tar_file_decoded = base64.b64decode(tar_file).decode('utf-8') in the lambda function.

HOW TARBALL IS PACKAGED:

To make this reproducible for someone else, the tarball is packaged as follows, in case the packaging affects its downstream unpacking requirements.

def package_tar_recursive_without_root_folder(self, input_dir: str, output_file: str): with tarfile.open(output_file, mode='w:gz') as archive: for root, dirs, files in os.walk(input_dir): for file in files: file_path = os.path.join(root, file) relative_path = os.path.relpath(file_path, input_dir) archive.add(file_path, arcname=relative_path, recursive=False)

API REQUEST:

The code that makes he API request from the remote python3 application starts with a tarball and sends the tarball as follows:

import requests

headers={
'Content-Type': 'application/x-tar',
'tar-ball-name': outputFile
}
files = {'file': open(outputFile, 'rb')}
response = requests.post(completeURL, headers=headers, files=files)


LAMBDA FUNCTION:

The relevant part of the lambda function that processes the API request in the AWS backend is as follows:

import base64
import tarfile
bodyTar = event['body']
# Get the base64 encoded tar file from the body
nameStr = 'filename="' + tarBallName + '"'
print("nameStr is: ", nameStr)
tar_file = bodyTar.split(nameStr)[1].split('\r\n\r\n')[1]
# Decode the base64 encoded tar file
print("About to decode the tar file.")
tar_file_decoded = base64.b64decode(tar_file).decode('utf-8') #This throws: ValueError: string argument should contain only ASCII characters

#The following code should run next, but the ERROR in the preceding line prevents the following code from running:
print("Done decoding the tar file.")
# Save the tar file to a temporary file
tmpTarBallName = '/tmp/' + tarBallName
print("tmpTarBallName is: ", tmpTarBallName)
with open(tmpTarBallName, 'wb') as f:
f.write(tar_file_decoded)
print("Done writing the tar file.")
# Extract the tar file
with tarfile.open(tmpTarBallName, 'r:gz') as tar:
tar.extractall('/tmp')

# Upload the extracted files to an S3 bucket
s3 = boto3.client('s3')
print("About to upload the extracted files to S3.")
s3.upload_file(tmpTarBallName, 'my-s3-bucket', tarBallName)


The code runs as expected until the line tar_file_decoded = base64.b64decode(tar_file).decode('utf-8') throws the error ValueError: string argument should contain only ASCII characters

What specific code needs to be changed above in order to successfully decode the tar file so that it can be processed and saved to an s3 bucket without throwing errors?

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