Question

A Rails gem titled omniauth-ebay which is compatible with Sinatra uses the code below to setup itself:

Rails.application.config.middleware.use OmniAuth::Builder do
       provider :ebay, "runame", "devid", "appid", "certid", "siteid", "apiurl"
    end

I know that omniauth (omniauth-ebay based on it) gem is definitely compatible with Sinatra. Note that that’s not a eBay or gem specific question, there certainly should be a generic way to setup a middleware in Sinatra.

Well, how do I change the code above to make it work with Sinatra?

Answer 1

You just need to understand what Rails is hiding from you. Rack middlewares are actually mounted directly inside of Rack.

In your config.ru file:

use OmniAuth::Builder do
  provider :ebay, "runame", "devid", "appid", "certid", "siteid", "apiurl"
end

The config.ru is loaded by Rack, so anything Rack-specific should go in there, unless you have some sort of system to put it elsewhere. I suspect Sinatra probably allows you to call #use from inside your Sinatra application, but still, config.ru will work in all cases.