Question

I want to do something what I thought will be a simple task:

• Have a form with these controls:
  • File upload for one file
  • Checkbox if this file should be extracted
  • Text input where I would specify which file should I link to (required only if the checkbox is checked) – index_file
• After submitting form:
  • If the checkbox isn’t checked, upload the file via CarrierWave to S3 to the specified store_dir
  • If the checkbox is checked, extract all files from the archive (I expect only ZIP archives; I need to keep the directory structure), upload extracted files to the specified store_dir and set the index_file in database (I don’t need to save to database anything about other extracted files)

As I have found, it isn’t an easy task because of Heroku limitations. These files will have a large size (hundreds of MiBs or a few GiBs), so I don’t want to redownload this file from S3 if possible.

I think that using Delayed Job or Resque might work, but I’m not exactly sure how to do it and what is the best solution of my problem.

Does anyone have any idea how to solve it with using the lowest resources as possible? I can change CarrierWave to another uploader (Paperclip etc.) and my hosting provider too if it isn’t possible on Heroku.

I was also thinking about using CloudFlare, would this still work without problems?

Thank you for answers.

Answer 1

Based on this heroku support email, it would seem that the /tmp directory is many gigs in size. You just need to clean up after yourself so Heroku as a platform is not the issue.

A couple of articles may help you solve the problem:

1. https://github.com/jnicklas/carrierwave/wiki/How-to%3A-Make-Carrierwave-work-on-Heroku – which explains how to configure your app to use the /tmp directory as the cache directory for CarrierWave. Pay attention to the following line:

   use Rack::Static, :urls => [‘/carrierwave’], :root => ‘tmp’ # adding this line

   This instructs rack to serve /carrierwave/xzy from the /tmp directory (useful for storing images temporarily)

2. Then, using the uploader.cache! method, you can deliberately cache the inbound uploaded file. Once stored, you can do checks to determine whether to call the uploader.store! method which will promote the contents to S3 (assuming you configured S3 as the store for CarrierWave.