Ruby script to ingest thumbnails for Ooyala Video Assets

ooyala_api_call_with_signature.rb

#!/usr/bin/env ruby
# Author : Ooyala
# Date   : 13-Jul-2018
# Purpose: Integrate with Ooyala API using signatures.
#          This script uses Ooyala's algorithm for signing http requests documented under
#          https://help.ooyala.com/video-platform/tasks/api_signing_requests.html
# Usage  : ruby ooyala_api_call_with_signature.rb
# Pre-requisites: Ooyala Backlot account api_key, secret, asset embed_code, sample jpg file.
#                 install necessary gems listed in require section.
# Example demonstrated: Using Ooyala API to ingest preview image file
require 'rubygems'
require 'base64'
require 'cgi'
require 'digest/sha2'
require 'net/http'
require 'rest-client'

class OoyalaApi
  DEFAULT_BASE_URL = 'http://api.ooyala.com'
  DEFAULT_EXPIRATION_WINDOW = 10*60 # 10 mins
  DEFAULT_API_KEY = '' #Ooyala api key
  DEFAULT_SECRET_KEY = '' #Ooyala api secret

  def generate_signature(http_method, request_path, query_params = {},
                         request_body = '')
    string_to_sign = DEFAULT_SECRET_KEY
    string_to_sign += http_method.to_s.upcase + request_path
    sorted_params = query_params.sort {|a, b| a[0].to_s <=> b[0].to_s}
    string_to_sign += sorted_params.map {|param| param.join('=')}.join
    string_to_sign += request_body.to_s
    signature = Base64::encode64(Digest::SHA256.digest(string_to_sign))[0..42]
    CGI.escape(signature)
  end

  def generate_api_call(http_method, request_path, query_params = {},
                        request_body = nil, version_no = '/v2/')

    http_method = http_method.to_s.upcase
    request_path = request_path unless request_path[0..3] == version_no
    original_params = Hash[*query_params.map {|k, v| [k.to_sym, v]}.flatten]
    query_params = sanitize_and_add_needed_parameters(query_params)
    query_params[:signature] ||= generate_signature(http_method, request_path, query_params.merge(original_params), request_body)
    build_url(http_method, request_path, query_params)
  end

  def sanitize_and_add_needed_parameters(params)
    params = Hash[*params.map {|k, v| [k.to_sym, CGI.escape(v.to_s)]}.flatten]
    params[:expires] = Time.now.to_i + DEFAULT_EXPIRATION_WINDOW
    params[:api_key] ||= DEFAULT_API_KEY
    params
  end

  def build_url(http_method, request_path, query_params = {})
    url = DEFAULT_BASE_URL
    url += request_path + '?'
    url + query_params.sort {|a, b| a[0].to_s <=> b[0].to_s}.map do |param|
      param.join("=")
    end.join("&")
  end
end

#initializing class
ooyala_api = OoyalaApi.new
params = {}
image_file_name = "./sample.jpg" # Path to the image file

request_body = File.open(image_file_name, "rb").read #Read file as binary
embed_code = "embed123" # Enter Ooyala video asset embed code
request_path = "/v2/assets/#{embed_code}/preview_image_files" #API for uploading preview image files
request_method = "POST" #SUPPORTED_HTTP_METHODS    = %w{GET POST PUT PATCH DELETE}

url_with_signature = ooyala_api.generate_api_call(request_method, request_path, params, request_body, "/v2/")
puts "\n" + "Calling URL with signature:" + "\n" + url_with_signature.to_s + "\n"

request = RestClient::Request.new(
    :method => request_method.to_s.downcase.to_sym,
    :url => url_with_signature,
    :payload => request_body)

response = request.execute
p "HTTP response code: #{response.code}"
p "Script Execution Completed"