Direct uploading to AWS S3
Since there are new regions of Amazon S3 services that accepts only Signature v4 (e.g. frankfurt) you cannot use
aws-sdk-v1 gem's #presigned_url functionality. And newer
aws-sdk gem (beeing stil in preview for 2.x) doesn't have a functionality to do direct uploading either. Here's my inplementation of that functionality, build on top of
For some basic information see this Heroku's Direct to S3 Image Uploads in Rails article https://devcenter.heroku.com/articles/direct-to-s3-image-uploads-in-rails . A "how to" by Amazaon itself in Authenticating Requests in Browser-Based Uploads Using POST (AWS Signature Version 4) http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-UsingHTTPPOST.html (notice beelow are subsections of details, like how to create signing policy).
An exapmle for simultaneous multiple images browser-based uploading
So, I build it the way,