Attachment_fu - watermark tmp file before saved to S3

Hi there,

I'd like to use RMagick to watermark an image in the tmp directory before Attachment_fu saves it to Amazon S3.

I took a look at the callbacks available in attachment_fu. There's an 'after_attachment_saved' method but this would be too late, and a 'before_thumbnail_saved' but this is no good because it's for thumbnails.

I think I need 'before_attachment_saved' or the equivalent in the attachment workflow.

I do have a watermark working for :file_system storage option using the code below.

# -------------------------------------------- watermark on file_system after initial save - but doesn't work for s3   def after_attachment_saved         unless self.thumbnail?           dst ="#{RAILS_ROOT}/public/# {self.public_filename}").first           src ="#{RAILS_ROOT}/config/ logo.png").first           result = dst.composite(src, Magick::SouthEastGravity, Magick::OverCompositeOp)           result.write("#{RAILS_ROOT}/public/#{self.public_filename}")         end     end

Now I'm looking for a way to hook into the attachment_fu process and apply the watermark before the main image is saved to :s3

Or perhaps I'm approaching this in the wrong way? I'm reluctant to start modifying the 'write_to_temp_file' method in the attachment_fu plugin.

Any help or advice anyone has would be much appreciated.

Many thanks, Will

I just got this working..

I added my own callback method 'before_attachment_save' to attachment_fu.rb . I hook into this in my attachment class and now have a great place to do my watermarking directly on the tmp file before it's sent off to S3.

If anyone is interested:

# -------- In attachment_fu.rb modification

def after_process_attachment   if @saved_attachment     if respond_to?(:process_attachment_with_processing) && thumbnailable? && !attachment_options[:thumbnails].blank? && parent_id.nil?       temp_file = temp_path || create_temp_file       attachment_options[:thumbnails].each { |suffix, size| create_or_update_thumbnail(temp_file, suffix, *size) }     end

    # ---- new added callback     callback :before_attachment_saved     save_to_storage     @temp_paths.clear     @saved_attachment = nil     callback :after_attachment_saved   end end

# --------- image_attachment.rb

def before_attachment_saved   unless self.thumbnail?     dst =     src ="#{RAILS_ROOT}/config/logo.png").first     result = dst.composite(src, Magick::SouthEastGravity, Magick::OverCompositeOp)     result.write(temp_path)   end end

There are some other bits and pieces you have to add in attachment_fu.rb to register the new callback method as well, but I copied this from the callbacks already there.

Just tested this on my host (heroku) and it's watermarking happily and storing on S3 :slight_smile:

Cheers, Will