Class: Datasets::Downloader

Inherits:
Object
  • Object
show all
Defined in:
lib/datasets/downloader.rb

Defined Under Namespace

Classes: ProgressReporter

Instance Method Summary collapse

Constructor Details

#initialize(url) ⇒ Downloader

Returns a new instance of Downloader.



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# File 'lib/datasets/downloader.rb', line 11

def initialize(url)
  if url.is_a?(URI::Generic)
    url = url.dup
  else
    url = URI.parse(url)
  end
  @url = url
  unless @url.is_a?(URI::HTTP)
    raise ArgumentError, "download URL must be HTTP or HTTPS: <#{@url}>"
  end
end

Instance Method Details

#download(output_path) ⇒ Object 



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# File 'lib/datasets/downloader.rb', line 23

def download(output_path)
  output_path.parent.mkpath

  headers = {"User-Agent" => "Red Datasets/#{VERSION}"}
  start = nil
  partial_output_path = Pathname.new("#{output_path}.partial")
  if partial_output_path.exist?
    start = partial_output_path.size
    headers["Range"] = "bytes=#{start}-"
  end

  Net::HTTP.start(@url.hostname,
                  @url.port,
                  :use_ssl => (@url.scheme == "https")) do |http|
    request = Net::HTTP::Get.new(@url.path, headers)
    http.request(request) do |response|
      case response
      when Net::HTTPPartialContent
        mode = "ab"
      when Net::HTTPSuccess
        start = nil
        mode = "wb"
      else
        break
      end

      base_name = @url.path.split("/").last
      size_current = 0
      size_max = response.content_length
      if start
        size_current += start
        size_max += start
      end
      progress_reporter = ProgressReporter.new(base_name, size_max)
      partial_output_path.open(mode) do |output|
        response.read_body do |chunk|
          size_current += chunk.bytesize
          progress_reporter.report(size_current)
          output.write(chunk)
        end
      end
    end
  end
  FileUtils.mv(partial_output_path, output_path)
end