Node frameworks usually work via (err, result) callbacks.
Is there a promise-based http framework for Node, with a healthy community and in active development (such as express)?
You might be interested in Joey written by Kris Kowal, the author of the Q promise library. There's not a large community, but Kris is often on the #montage irc channel on freenode to offer help.
I had the same question you had today, and I found q-io, also by kriskowal. It uses Q.js to promise-wrap filesystem io as well as server and http client.
I have not tried it out yet, but it definitely does not seem to have an active community built around it at this point. Sad thing to see, in a world filled with callback pyramids of doom.
For HTTP clients, I like http://www.npmjs.org/package/httpinvoke.
For HTTP servers, I like https://github.com/mjackson/mach ; it's great!
Then again, I'm not such a huge fan httpinvoke either, I works and it's okay. But I think the API is more complicated than it needs to be and I find it hard to debug. I might be missing something.
Alternatively, I use recommend kew (fast promise implementation) to wrap callback style methods.