sellingpartnerapi.rb

require 'aws-sigv4'
require 'httparty'

AWS_API_ENDPONT = 'https://sandbox.sellingpartnerapi-na.amazon.com'

# https://stackoverflow.com/questions/65669679/amazon-selling-partner-api-signed-request-ruby-implementation
module Net::HTTPHeader
  def capitalize(name)
    name
  end
  private :capitalize
end

class AWSSellerMigration
  def get_auth_token
    begin
      response = HTTParty.post('http://api.amazon.com/auth/o2/token', body: {
        "grant_type": "client_credentials",
        "scope": "sellingpartnerapi::migration",
        "client_id": "" #CLIENT_ID,
        "client_secret": "" #CLIENT_SECRET
      })

      response['access_token']
    rescue
    end
  end

  def get_request_headers(request_url)
    signer = Aws::Sigv4::Signer.new(
      service: 'execute-api',
      region: 'us-east-1',
      # static credentials
      access_key_id: "" #ACCESS_KEY_ID,
      secret_access_key: ""
    )

    signature = signer.sign_request(
      http_method: 'GET',
      url: request_url,
    )

    signature.headers.merge({
      'x-amz-access-token' => get_auth_token,
      'user-agent' => 'App/1.0 (Language=Ruby)'
    })
  end

  def get_authorization_code
    request_url = "#{AWS_API_ENDPONT}/authorization/v1/authorizationCode"

    begin
      headers = get_request_headers(request_url)
      response = HTTParty.get(request_url, headers: headers, query: {
        "developerId" => "",
        "mwsAuthToken" => "",
        "sellingPartnerId" => ""
      })

      response['payload']['authorizationCode']
    rescue
    end
  end

  def get_refresh_token
    begin
      response = HTTParty.post('https://api.amazon.com/auth/o2/token', body: {
        "grant_type": "authorization_code",
        "code": get_authorization_code,
        "client_id": "",
        "client_secret": "",
        "redirect_uri": "https://link_to_receive refresh token"
      })

      puts response
    rescue
    end
  end
  
  def refreshed_token
    data = {
      "grant_type" => "refresh_token",
      "refresh_token" => "",
      "client_id" =>  "",
    }

    response = HTTParty.post("https://api.amazon.com/auth/o2/token", body: data)
    puts response
  end
end

migration = AWSSellerMigration.new
migration.refreshed_token
# puts migration.get_refresh_token