goliath server that echoes embedded html image (jpeg)

streaming_echoed_image_service.rb

require 'goliath'
require 'base64'

class StreamingEchoedImageService < Goliath::API
  def on_headers(env, headers)
    env.logger.info "#{env['REQUEST_METHOD']} #{env['REQUEST_URI']}"

    env.logger.info 'received headers: ' + headers.inspect
    env['async-headers'] = headers
  end

  def on_body(env, data)
    env.logger.info 'received data: ' + data.size.to_s
    (env['async-body'] ||= '') << data
  end

  def on_close(env)
    env.logger.info 'closing connection'
  end

  def response(env)
    env.logger.info "total data size: #{env['async-body'].size} bytes"

    base64_image_data = Base64.encode64(env['async-body'])
    html = "<img src='data:image/jpeg;base64,#{base64_image_data}'/>"

    [200, {"Content-Type"=>"text/html"}, html]
  end
end