promptworks/stacker_bee

require 'faraday'
require 'base64'

module StackerBee
  module HTTPMiddleware
    class SignedQuery < Faraday::Middleware
      def initialize(app, key)
        @key = key
        fail 'Key cannot be nil' unless @key
        super app
      end

      def call(env)
        sign_uri env[:url]
        @app.call(env)
      end

      def sign_uri(uri)
        downcased  = uri.query.downcase
        nonplussed = downcased.gsub('+', '%20')
        signed     = OpenSSL::HMAC.digest('sha1', @key, nonplussed)
        encoded    = Base64.encode64(signed).chomp
        escaped    = CGI.escape(encoded)

        uri.query << "&signature=#{escaped}"
      end
    end
  end
end