src/uri_utilities.rb

   1 #
   2 # Copyright Michael Orlitzky
   3 #
   4 # http://michael.orlitzky.com/
   5 #
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 # GNU General Public License for more details.
  15 #
  16 # http://www.fsf.org/licensing/licenses/gpl.html
  17 #
  18
  19 require 'open-uri'
  20 require 'vendor/ruby-progressbar/progressbar'
  21
  22 # Just a couple of convenience methods for URIs.
  23 # These could be monkey-patched in, but with only
  24 # a few methods, that'd be asking (unnecessarily)
  25 # for trouble.
  26 class UriUtilities
  27
  28   # Get the filename portion of a given URI.
  29   # Return nil if there is no filename portion.
  30   def get_filename(uri)
  31     return uri.path.split('/').last
  32   end
  33
  34
  35   # Download the given URI object to <outfile_name>.
  36   # Should use the progress_proc parameter to show
  37   # a progress bar using the Ruby/ProgressBar library.
  38   def download_with_progress_bar(uri, outfile_name)
  39     # We wrap the whole thing in a begin/rescue so that
  40     # we can clean up afterwards in case of an error.
  41     begin
  42       open(outfile_name, 'wb') do |outfile|
  43         pbar = nil
  44         uri.open(:content_length_proc => lambda {|content_length|
  45                    if content_length && (0 < content_length)
  46                      pbar = ProgressBar.new("Download", content_length)
  47                      pbar.instance_eval { @bar_mark = '=' }
  48                      pbar.file_transfer_mode
  49                    end
  50                  },
  51                  :progress_proc => lambda {|size|
  52                    pbar.set(size) if pbar
  53                  }) do |video_file|
  54           outfile.write(video_file.read)
  55         end
  56       end
  57
  58       # Toss out an empty line to get rid of the progress bar.
  59       # Normally, it would remain on the shell's "current" line.
  60       puts ''
  61
  62     rescue Errno::EACCES => e
  63       # Don't delete the file if it's unwritable.
  64       raise(e)
  65     rescue => e
  66       # Here we get rid of the output file if there was an error.
  67       # We test File.exists? first since the first line, the open()
  68       # call, could theoretically fail.
  69       File.delete(outfile_name) if File.exists?(outfile_name)
  70       raise(e)
  71     end
  72   end
  73
  74 end