Stream AWS S3 Files using Boto3

boto3-s3-flask-stream.py

# Demonstration only

from flask import current_app as app, Response
import boto3 # boto3==1.13.25
import botocore # botocore==1.16.25

CHUNK_SIZE = 256*1024 # 256kb

def get(a_bucket, a_file)
    s3 = boto3.client('s3')
    try:

        response = s3.get_object(Bucket=a_bucket, Key=a_file)

        data_stream = response['Body']
        content_type = response['ContentType']
        headers = {'Content-Disposition': 'attachment;filename=' + a_file}
        
        return Response(data_stream.iter_chunks(CHUNK_SIZE), mimetype=content_type, headers=headers)

    except botocore.exceptions.ClientError as e:
        app.logger.exception('No such file exists: {}'.format(e))
        return 'Not Found', 404
 
# Feel free to give suggestions, we can improve this.