Download.dropzone

#!/usr/bin/ruby

# Dropzone Destination Info
# Name: Download
# Description: Download files
# Handles: NSStringPboardType
# Events: Dragged
# Creator: Marc E.
# URL: http://www.jardinpresente.com.ar/svn/utiles/trunk/dropzone/Download.dropzone
# IconURL: http://aptonic.com/destinations/icons/network.png
# OptionsNIB: ChooseFolder

require 'net/http'

# We put net/http/stats here instead of require
# Source: http://blog.obloh.com/posts/show/5


# Add methods to have stats and rules when downloading.
class Net::HTTP
    # This methods has the same behavior than get_response. However the block takes
    # 2 arguments (response and a string of bytes). Bytes must not be retrieve
    # via response.bytes_read, because they have already been read to compute stats.
    #
    #  require 'net/http' 
    #  require 'net/http/stats' 
    #
    #  content = '' 
    #  uri = URI.parse('http://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.6.tar.gz') 
    #  response = Net::HTTP.get_response_with_stats(uri) do |resp, bytes| 
    #    content << bytes 
    #    puts "#{resp.bytes_percent}% downloaded at #{(resp.bytes_rate / 1024).to_i} Ko/s, remaining #{resp.left_time.to_i} seconds" 
    #  end
    # This script will print something like:
    #  13% downloaded at 59 Ko/s, remaining 65 seconds
    # See Net::HTTP::Stats to know more about attributes.
    def self.get_response_with_stats(url, &block)
        response = Net::HTTP.get_response(url) do |resp|
            resp.extend(Net::HTTP::Stats)
            resp.initialize_stats
            resp.read_body do |bytes|
                resp.bytes_read += bytes.size
                block.call(resp, bytes) if block
            end
        end
        response
    end 

    # This method works exactly as Net::HTTP.get_response_with_stats, but it takes
    # a 2nd Hash argument which describes rules.
    # Raises Net::HTTP::Stats::MaxSizeExceed, Net::HTTP::Stats::MaxSpentTimeExceed
    # or Net::HTTP::Stats::MaxLeftTimeExceed if a rule isn't respected.
    #   
    #  require 'net/http' 
    #  require 'net/http/stats'
    #  
    #  rules = { 
    #    # Download is interrupted if spent time is greater (in sec). 
    #    :max_time => 5 * 60, 
    #    # Download is interrupted if estimated time is greater (in sec). 
    #    :max_left_time => 5 * 60, 
    #    # Download is interrupted if body is greater (in byte). 
    #    :max_size => 50 * 1024 * 1024, 
    #    # Wait some time before checking max_time and max_left_time (in sec). 
    #    # something between 5 and 20 seconds should be good. 
    #    :min_time => 15 
    #  }
    #  
    #  content = '' 
    #  uri = URI.parse('http://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.6.tar.gz') 
    #  response = Net::HTTP.get_response_with_rules(uri, rules) do |resp, bytes| 
    #    content << bytes 
    #  end
    def self.get_response_with_rules(url, rules, &block)
        response = Net::HTTP.get_response_with_stats(url) do |resp, bytes|
            msg = ''
            if resp.bytes_count > rules[:max_size]
                raise Stats::MaxSizeExceed.new("Response size (#{resp.bytes_count}) exceed maximun content length allowed (#{rules[:max_size]}).", resp)
            elsif resp.spent_time > rules[:max_time]
                raise Stats::MaxSpentTimeExceed.new("Maximun time allowed (#{rules[:max_time]}) have been exceed", resp)
            elsif resp.spent_time > rules[:min_time] and resp.left_time > rules[:max_left_time]
                raise Stats::MaxLeftTimeExceed.new("Left time expected (#{resp.left_time.to_i}) exceed maximun left time allowed (#{rules[:max_left_time]})", resp)
            end
            block.call(resp, bytes) if block
        end
        response
    end

    module Stats
        # Body size
        attr_accessor :bytes_count

        # Bytes already downloaded
        attr_accessor :bytes_read

        # Rate (byte/sec)
        attr_accessor :bytes_rate

        # Percent of bytes downloaded
        attr_accessor :bytes_percent

        # Spent time (second)
        attr_accessor :spent_time

        # Remaining time (second)
        attr_accessor :left_time

        # When the download started (Time)
        attr_accessor :started_at

        # Called by Net::HTTP.get_response_with_stats.
        def initialize_stats #:nodoc:
            @bytes_count = self['content-length'].to_i
            @bytes_read = 0
            @bytes_rate = 0
            @bytes_percent = 0
            @spend_time = 0
            @left_time = 0
            @started_at = Time.now
        end

        # Updates stats.
        def bytes_read=(bytes_read) #:nodoc:
            @bytes_read = bytes_read
            @spent_time = Time.now - @started_at
            @bytes_rate = @bytes_read / @spent_time if @spent_time != 0
            @left_time = (@bytes_count - @bytes_read) / @bytes_rate if @bytes_rate != 0
            @bytes_percent = @bytes_read * 100 / @bytes_count if @bytes_count != 0
            @bytes_read
        end

        # Generic error class. Should not be instanced.
        class Error < Net::HTTPError
        end

        # Raised if downloaded file is too big.
        class MaxSizeExceed < Net::HTTP::Stats::Error
        end

        # Raised if spent time is to long.
        class MaxSpentTimeExceed < Net::HTTP::Stats::Error
        end

        # Raised if remaining time is too long.
        class MaxLeftTimeExceed < Net::HTTP::Stats::Error
        end
    end
end

def dragged
    urls = $items[0].split("\n")
    
    $dz.determinate(false)

    urls.each_with_index do |url, index|
      $dz.begin("Downloading file #{index+1} of #{urls.length}...")
      item = url.gsub(/\[/, '%5B').gsub(/\]/, '%5D').chomp
    
      uri = URI.parse(URI.escape(item))
      filename = url.split(File::SEPARATOR)[-1].chomp

      $dz.determinate(true)

      tmp_file = File.join('/tmp/', filename)

      File.open(tmp_file, 'w') do |file|
        response = Net::HTTP.get_response_with_stats(uri) do |resp, bytes| 
          file.write(bytes)
          $dz.percent(resp.bytes_percent)
        end
      end
    
      Rsync.do_copy(tmp_file, ENV['EXTRA_PATH'], true)
    end

    $dz.finish("Download complete")
    $dz.url(false)
end