Honestly this is how all development should be done. Treat the web server as yet another interface into your application to keep it as slim as possible. Need to change web servers, support thrift, avro, etc? Just write another interface that hooks into your application. Easy!

There are plenty of examples in every language where a web framework turns into a web service + caching + session management + ORM + whatever else you can think of then you use all of those features and now you're inflexible, can't easily add new interfaces without seriously rewriting the old and good luck if you need to move away from that web framework for whatever reason.