chunked file stream with goliath

client.rb

require 'bundler'
Bundler.require

url = 'http://0.0.0.0:9000/images/avatar.png'

EM.run do
  http = EventMachine::HttpRequest.new(url).get
  http.stream  {|chunk| print [:chunk, chunk.size] }
  http.headers {|h| p [:headers, h] }

  http.callback do
    p ["Done", http.response.size]
    EM.stop
  end

  http.errback do
    p ["Error", http]
    EM.stop
  end
end

file_system.rb

require 'uri'

module Store
  class FileSystem
    CHUNKSIZE = 65536

    def initialize(uri)
      @uri  = uri
    end

    def get
      open(@uri, "rb") do |file|
        yield file.read(CHUNKSIZE) until file.eof?
      end
    end
  end
end

server.rb

require 'bundler'
Bundler.require

require 'file_system'

class GetImage < Goliath::API
  use Goliath::Rack::Render, 'json'

  def response(env)
    uri     = params[:id]
    headers = {'X-filename' => params[:id]}

    operation = proc do
      Store::FileSystem.new(uri).get { |chunk| env.chunked_stream_send(chunk) }
    end

    callback = proc do |result|
      env.chunked_stream_close
    end

    EM.defer operation, callback

    headers.merge!( 'X-Stream' => 'Goliath')
    chunked_streaming_response(200, headers)
  end
  
  def on_close(env)
    env.logger.info "Stream closed"
  end
end

class Server < Goliath::API
  use Goliath::Rack::Heartbeat
  use Goliath::Rack::Params

  get '/images/:id', GetImage
end