Long polling (comet) on Rails

Hello!

I’d like to share some concepts with community regarding asynchronous operations in Rails, hoping for feedback and advice. We (Helicon Tech) currently work on Ruby on Rails implementation for Microsoft IIS. Our goal is to make RoR available for shared Windows hostings and developers. We currently work with several small hostings to implement RoR shared hosting solution with them as proof of concept.

So I was thinking… since we already have a working asynchronous server implementation and asynchronous (after some tweaking) implementation of FastCGI, we may utilize it to bring async into the RoR applications.

Our concept is quite easy. I will show it on a simple chat application example: Our server creates a fiber and puts a Rack call into the fiber body, so all RoR code, like controller is executed inside a fiber. There is a script to wait for new messages, which simply yields (suspends) a fiber. So there could be number, maybe thousands of suspended fibers at a time. When new message is received it is put into the storage and all fibers waiting for it are resumed. They process messages, return responses to their clients and then clients makes another request to a wait script.

We have working proof of concept for it, but I need a feedback from the community. Whether this future is needed at all and what possible problems and flaws I need to take into consideration?

Also I am thinking on how to extend this concept to bring more asynchronous operations into RoR. Imagine we have some time consuming operation in the script. Like we are requesting whether forecast data from remote server for analysis. We could start an asynchronous http request operation, setting up a resume of current fiber as a callback, and then suspend current fiber, allowing other requests to be served. Such system could handle much more load that a synchronous system. Unfortunately I cannot find appropriate concept of asynchronous operations for Ruby – how to do an async HTTP request? Some use 'eventmachine' to do this. But while providing some asynchronous operation support inside event loop, the loop itself completely blocks execution thread. I think we may try to put our entire client-server conversation into the event loop, need to try it first. Anyway any feedback and suggestions are greatly appreciated.

Thank you!