Class: Datasets::Downloader

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

Defined Under Namespace

Classes: ProgressReporter, TooManyRedirects

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 13

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 25

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

  start_http(@url, headers) do |response|
    if response.is_a?(Net::HTTPPartialContent)
      mode = "ab"
    else
      start = nil
      mode = "wb"
    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
  FileUtils.mv(partial_output_path, output_path)
rescue TooManyRedirects => error
  last_url = error.message[/\Atoo many redirections: (.+)\z/, 1]
  raise TooManyRedirects, "too many redirections: #{@url} .. #{last_url}"
end