Paperclip post process - How to compress image using jpegoptim/optpng - ruby-on-rails-3

Question

I would like to use jpegoptim or optipng to compress the image uploaded by users via Paperclip.
I have a Paperclip model configured as:
has_attached_file :image,
:styles => {:thumb => '50x50>', :preview => '270x270>' },
:url => "/system/:class/:attachment/:id/:basename_:style.:extension",
:path => ":rails_root/public/system/:class/:attachment/:id/:basename_:style.:extension"
Question 1:
Is it possible to compress the original image uploaded by user, then let Paperclip resize it , so there's only one compress process? and how to do it?
Question 2:
I am going to do it via the after_post_process callback, and I could get all the instances of three files from image.queued_for_write and I would like to trigger jpegoptim/optipng by the file extension, but when I use current_format = File.extname(file.path), I get something like: .jpg20120508-7991-cqcpf2. Is there away to get the extension string jpg? or is it safe that I just check if the extension string is contained in that string?

Answer 1

Since there's no other answers, here is how I do it in my project and it seems it's being working ok for several months.
class AttachedImage < ActiveRecord::Base
belongs_to :attachable, :polymorphic => true
validates_attachment_presence :image
validates_attachment_content_type :image, :content_type=>['image/jpeg', 'image/png', 'image/gif']
has_attached_file :image,
:styles => {:thumb => '50x50>', :preview => '270x270>' },
# :processors => [:image_compressor],
:url => "/system/:class/:attachment/:id/:basename_:style.:extension",
:path => ":rails_root/public/system/:class/:attachment/:id/:basename_:style.:extension"
after_post_process :compress
private
def compress
current_format = File.extname(image.queued_for_write[:original].path)
image.queued_for_write.each do |key, file|
reg_jpegoptim = /(jpg|jpeg|jfif)/i
reg_optipng = /(png|bmp|gif|pnm|tiff)/i
logger.info("Processing compression: key: #{key} - file: #{file.path} - ext: #{current_format}")
if current_format =~ reg_jpegoptim
compress_with_jpegoptim(file)
elsif current_format =~ reg_optipng
compress_with_optpng(file)
else
logger.info("File: #{file.path} is not compressed!")
end
end
end
def compress_with_jpegoptim(file)
current_size = File.size(file.path)
Paperclip.run("jpegoptim", "-o --strip-all #{file.path}")
compressed_size = File.size(file.path)
compressed_ratio = (current_size - compressed_size) / current_size.to_f
logger.debug("#{current_size} - #{compressed_size} - #{compressed_ratio}")
logger.debug("JPEG family compressed, compressed: #{ '%.2f' % (compressed_ratio * 100) }%")
end
def compress_with_optpng(file)
current_size = File.size(file.path)
Paperclip.run("optipng", "-o7 --strip=all #{file.path}")
compressed_size = File.size(file.path)
compressed_ratio = (current_size - compressed_size) / current_size.to_f
logger.debug("#{current_size} - #{compressed_size} - #{compressed_ratio}")
logger.debug("PNG family compressed, compressed: #{ '%.2f' % (compressed_ratio * 100) }%")
end
end

Answer 2

There are also some gems to optimize paperclip images:
paperclip-optimizer
paperclip-compressor

Answer 3

Might be a performance compromise but I got images better compressed with FFMPEG or AVCONV.
sudo apt-get install ffmpeg
= initializer
Paperclip.options[:command_path] = "/usr/bin/" # see `which ffmpeg`
= Modal
after_save :compress_with_ffmpeg
def compress_with_ffmpeg
[:thumb, :original, :medium].each do |type|
img_path = self.avtar.path(type)
Paperclip.run("ffmpeg", " -i #{img_path} #{img_path}")
end
end
I got 1.7MB image compressed to 302.9KB!!!