Carrierwave Custom Version

gistfile1.txt

class CustomUploader < CarrierWave::Uploader::Base

  # complete example of custom carrierwave version generator that does not use manipulate with hopefully helpful comments
  # in this case we are uploading a .psd (photoshop file) and then rendering to a png.  We want to 
  # save the original psd, so we create a png version.

  storage :file

  version :png do  # tells carrierwave to generate a new version of the upload in this case a "png"
    
    # step one:  generate the png
    
    process :generate_custom_png  
    
    # optional step two:  rename the file name from something like "png_xxx.psd" to "xxx.png"
    # note that for version :zzz you would change all references to from png to zzz
    
    # by putting full_filename inside the version block this seems to only modify the behavior for this specific version
    
    def full_filename(for_file) 
      super.chomp(File.extname(super)).gsub('png_','') + '.png'
    end
      
  end    

  def generate_custom_png
  
    # when this method is called current_path is pointing to a copy
    # of the original file
    # the methods job is to rewrite the file to whatever the new version should be
    # in this case its easy, but sometimes the underlying conversion process
    # needs to seperate input and output files.
    # In that case first mv the file to a new file with same name plus ".tmp" on the end
    # process that file, with the output going to the "current_path" file.
    
    puts "converting #{original_filename} to #{current_path}"  # note that the file names will still be messed up at this point
    
    # in this example we are using the PSD gem to read a PSD file and turn it into a PNG.
    
    PSD.open(current_path) do |f| 
      begin
        f.tree.save_as_png(current_path)
      rescue Exception => e
        # this optional but shows how I handle any errors arising during the conversion.
        # in this case the model has a processing_errors string that we concat the error message onto
        model.processing_errors = 
          [model.processing_errors, "Could not generate background png: #{e.message}"].compact.join("/n")
      end
    end
  end
end

Thank you - very useful

Thank you. I struggled exactly.