AwsSigner for Ruby

A gem to help with creating signed URLs for uploading files direct to S3.

Installation

gem install aws_signer

or in your Gemfile

gem 'aws_signer'

Usage

Make sure you require the library.

require 'aws_signer'

Configuration

You will need to setup a few configuration options before using the library:

AwsSigner.configure do |configuration|
  # The S3 bucket you want to upload to
  configuration.upload_bucket = 'my-bucket'
  # Your AWS Secret Access Key
  configuration.secret_access_key = 'SECRETACCESSKEY'
  # Your Access Key ID
  configuration.access_key_id = 'ACCESSKEYID'
end

Creating Signed URLs

Created a signed URL is as easy as passing in a file name and a mime type:

signer = AwsSigner.signature(:file_name => 'image.jpg', :mime_type => 'image/jpg')
# Return the public URL for the file.
signer.public_url
# Return the signed URL for the file.
signer.signed_url

The object returned responds to #to_json, so you can use it in a Rails controller like so:

class AwsSignaturesController < ApplicationController
  def create
    signer = AwsSigner.signature(signature_parameters)
    render :json => signer, :status => 201
  end

  protected

  def signature_parameters
    params.require(:file_name)
    params.require(:mime_type)
    params
  end
end

That controller action would return a JSON payload that looks something like this:

{
    "public_url": "https://s3.amazonaws.com/my-bucket/2014/07/31/03/04/42c842de85749a1723c98ca2932a3b6a/image.jpg",
    "signed_url": "https://s3.amazonaws.com/my-bucket/2014/07/31/03/04/42c842de85749a1723c98ca2932a3b6a/image.jpg?AWSAccessKeyId=ACCESSKEYID&Expires=1406776178&Signature=77DZuYVRYqZHjw9zqwipBiZrmUY%3D"
}

Contributing to aws_signer