Rubyのaws-sdkでプロキシを使う

AWS S3 
require "aws-sdk"

config = {
  :access_key_id     => "access key id",
  :secret_access_key => "secret access key",
  :proxy_uri => "http://127.0.0.1:8080"
}

AWS.config(config)

s3 = AWS::S3.new