Is Rails Paperclip only for Images?

问题

Are there any rails libraries for managing file attachments connected with ActiveRecord?

I know paperclip, but it seems suitable for images primarily. They indeed mention audio and pdf files on the github project page, but there's no further explanation about the usage of different file types. Attributes like :style would change their meaning if you uploaded an audio file. So different file sizes wouldn't be expressed in a two-dimensional resolution but in terms of bitrates.

Are there any alternatives to paperclip? Or is it possible to not just link imagemagick with paperclip but for example ffmpeg?

回答1:

There's no reason you couldn't use Paperclip for other types of files, but if you want an alternative you can't go wrong with CarrierWave.

回答2:

The question above contains more than one facette. So I'll try to answer them all one-by-one.

Paperclip::Processor

It is possible to use paperclip for other files than images. You can define custom import actions by subclassing Paperclip::Processor. The following code shows a minimal structure of a custom processor implementation. This can be adapted to any file type with custom options.

module Paperclip
  class FileContents < Processor

    def initialize file, options = {}, attachment = nil
      @file           = file
      @options        = options
      @instance       = attachment.instance
      @current_format = File.extname(attachment.instance.asset_file_name)
      @basename       = File.basename(@file.path, @current_format)
      @whiny          = options[:whiny].nil? ? true : options[:whiny]
    end

    def make
      begin

        # your import code (e.g. ocr or video resizing)...

        @file
      rescue StandardError => e
        raise PaperclipError, "There was an error processing the file contents for #{@basename} - #{e}" if @whiny
      end
    end
  end
end

paperclip and ffmpeg

Someone wrote a paperclip processor for video files already. Have a look at the source of paperclip-ffmpeg gem to see how complex processors are written.