undefined method `join' for #<String:0x007f4d59c9f8f8>

[the-net-tech]

New rails 4.2 installation

[steveo7]

I'm encountering this same error, Rails 4.2 Ruby 2.2.0. The error is coming from Sinatra.

[steveo7]

After further troubleshooting, I'm convinced the problem is it does not support Mongoid, which is what I'm using. @the-tech-net, are you using Mongoid?

[benjaminharel]

Yes this is the problem. But what is the solution?

[steveo7]

I suppose somebody with the time and talent could add Mongoid support and submit a pull request. Of which I have neither!

[johnmaxwell]

I was having the same issue after upgrading to Rails 4.2. I'm not using Mongoid or Mongo. In my case, I was mounting DelayedJobWeb in config.ru, instead of mounting it as a route in config/routes.rb. I had been doing this on an older version of delayed_job_web for a couple of years. When I followed the instructions in the README to mount it in config/routes.rb, I bypassed this error.