sized.rb

# Allow the metal piece to run in isolation
require(File.dirname(__FILE__) + "/../../config/environment") unless defined?(Rails)

#
# allow users to request an image to be of a specific size
#
# e.g.
#
#   /sized/#{siteid}-#{fileId}-x-y.png
#
class Sized
  def self.call(env)
    if env["PATH_INFO"] =~ /^\/sized/
      path = env["PATH_INFO"].gsub(/\/sized\//,'')
      parts = path.split('-')
      site = parts[0]
      filekey = parts[1]
      width = parts[2]
      height = parts[3]
      ext = File.extname(path)
      return [500, {"Content-Type" => "text/plain"}, ["Error invalid size request"]] if(width.nil? or height.nil? or filekey.nil? or site.nil?)
      width = width.to_i
      height = height.to_i
      return [500, {"Content-Type" => "text/plain"}, ["Error invalid size request"]] if(width == 0 or height == 0 or width > 1023 or height > 768)
      file_path = File.join(RAILS_ROOT,'public','files',site,"#{filekey}#{ext}")
      #files = Dir["#{File.join(RAILS_ROOT,'public','files',site,filekey)}*.*"]
      begin
        new_path = File.join(RAILS_ROOT,'public','files',site,"#{filekey}-#{width}-#{height}#{ext}")
        if File.exist?(new_path)
          return [200, {"X-Accel-Redirect" => "/files/#{site}/#{filekey}-#{width}-#{height}#{ext}", "Content-Type" => "image/#{ext.gsub(/\./,'')}"},[]]
        end
        return [404, {"Content-Type" => "text/html"}, ["Not Found"]] if !File.exist?(file_path)
        new_image = Magick::Image.read(file_path).first.resize_to_fill(width, height)
        new_image.write(new_path) { self.quality = 70 }
        #new_image.quantize(number_colors=512,  # maybe this is an options?
        #                   colorspace=Magick::RGBColorspace,
        #                   dither=true,
        #                   tree_depth=0,
        #                   measure_error=true).write(new_path) { self.quality = 70 }
        [200, {"X-Accel-Redirect" => "/files/#{site}/#{filekey}-#{width}-#{height}#{ext}", "Content-Type" => "image/#{ext.gsub(/\./,'')}"},[]]
      rescue => e
        STDERR.puts e.message
        STDERR.puts e.backtrace.join("\n")
        [200, {"X-Accel-Redirect" => "/files/#{site}/#{filekey}#{ext}", "Content-Type" => "image/#{ext.gsub(/\./,'')}"},[]]
      end
    else
      [404, {"Content-Type" => "text/html"}, ["Not Found"]]
    end
  end
end