specify_content_type_s3.py

import boto3

s3 = boto3.client("s3")
bucket_name = "annageller"
s3_object = "sales/customers.csv"
local_file_path = f"/Users/annageller/Desktop/datasets/{s3_object}"

# Uploading without specifying content type
s3.upload_file(
    local_file_path,
    bucket_name,
    s3_object
)
response = s3.head_object(Bucket=bucket_name, Key=s3_object)
print(response["ResponseMetadata"]["HTTPHeaders"]["content-type"])  # binary/octet-stream

# Uploading with specifying content type: text/csv
s3.upload_file(
    local_file_path,
    bucket_name,
    s3_object,
    ExtraArgs={'ContentType': 'text/csv'}
)
response = s3.head_object(Bucket=bucket_name, Key=s3_object)
print(response["ResponseMetadata"]["HTTPHeaders"]["content-type"])  # text/csv