Testing Rails+Webhooks with Cucumber

I'm trying to integrate my rails application with an external service. I'm using Cucumber to do integration testing and I'd don't want to mock out the external service at times. When I get webhooks from this service, they are routed to apache running my development environment. This would be easy to fix if I could figure out how to fixate my cucumber rails process on a particular port or how to proxy to it.

Basically, how do I get external webhooks (P开发者_运维问答OSTs) routed to my cucumber rails process while it's running?

It appears that this is possible with Selenium as it starts a webserver on a configurable port.

I contacted the author of this blog post and he confirmed that he was using Selenium configured on the port he forwarded with localtunnel.