How do you access the raw content of a file uploaded with Paperclip / Ruby on Rails?

Question

I'm using Paperclip / S3 for file uploading. I upload text-like files (not .txt, but they are essentially a .txt). In a show controller, I want to be able to get the contents of the uploaded file, but don't see contents as one of its attributes. What can I do here?

attachment_file_name: "test.md", attachment_content_type: "application/octet-stream", attachment_file_size: 58, attachment_updated_at: "2011-06-22 01:01:40"

PS - Seems like all the Paperclip tutorials are about images, not text files.

Answer 1

Here's how I access the raw contents of my attachment:

class Document

  has_attached_file :revision

  def revision_contents
    revision.copy_to_local_file.read
  end

end

Please note, I've omitted my paperclip configuration options and any sort of error handling.

Answer 2

In Paperclip 3.0.1 you could just use the io_adapter which doesn't require writing to (and removing from) the local file system.

Paperclip.io_adapters.for(attachment.file).read

Answer 3

To access the file you can use the path method: csv_file.path http://rdoc.info/gems/paperclip/Paperclip/Attachment#path-instance_method

This can be used along with for example the CSV reader.

Answer 4

@jon-m answer needs to be updated to reflect the latest changes to paperclip, in order for this to work needs to change to something like:

class Document

  has_attached_file :revision

  def revision_contents(path = 'tmp/tmp.any')
    revision.copy_to_local_file :original, path
    File.open(path).read
  end
end

A bit convoluted as @jwadsack mentioned using Paperclip.io_adapters.for method accomplishes the same and seems like a better, cleaner way to do this IMHO.

Answer 5

You would need to load the contents of the file (using Rubys File.open) into a variable before you show it. This may be an expensive operation if your app gets lots of use, so it may be worthwhile reading the contents of the file and putting it into a text column in your database after uploading it.

Answer 6

Attachment already inherits from IOStream. http://rdoc.info/github/thoughtbot/paperclip/master/Paperclip/Attachment

So it should just be "#{attachment}" or <% RDiscount.new(attachment).to_html %> or send_data(attachment). However you wanted to display the data.