In our Ruby on Rails web applications, we use Amazon S3 to store files. Uploading files to Amazon S3 buckets via HTTP requests requires signing the request. The current recommended, and safe signing method is Signature Version 4, and AWS regions opened after January 30, 2014, such as London and Frankfurt, only support this version.
In this blog post, I will try to explain how to sign HTTP requests for Amazon S3 uploads in a Rails application and make requests by using AngularJS ng-file-upload module. Read more at Signing S3 Upload Requests With Signature Version 4 in a Rails and AngularJS Application post.