Howto provide a single page preview for PDF & TXT with carrierwave

Assert rmagick provision ...

Gemfile

gem 'rmagick', '2.13.2' # at this moment the latest stable version

config/initializer/carrierwave.rb

require 'carrierwave/processing/rmagick'

... and define a custom processor

MyUploader.rb

class MyUploader < CarrierWave::Uploader::Base
  include CarrierWave::RMagick

  def cover
    manipulate! do |frame, index|
      frame if index.zero? # take only the first page of the file
    end
  end

  version :preview do
    process :cover
    process :resize_to_fit => [310, 438]
    process :convert => :jpg

    def full_filename (for_file = model.source.file)
      super.chomp(File.extname(super)) + '.jpg'
    end
  end

  ... # the other stuff

end

Notes

Only PDF and TXT files (and of course images) are previewable to my knowledge till dato.
Don't forget to provide rmagick on your server

Martin Straub

Say thanks3

Last edit

2015-04-20

Deleted user #3651

License

Source code in this card is licensed under the MIT License.

Posted by Martin Straub to makandra dev (2013-12-05 09:07)