catch processing errors and emit them as events

[demmer]

Previously, if the server received a malformed packet, the request processing would throw an uncaught error which can end up killing the node process.

Instead, add a try ... catch handler around the Request / Response processing and trigger an error event which can be caught and handled gracefully. Include an error message, the actual Error object, and the connection info in the event callback so aid debugging and make it possible to log where the bogus requests are coming from.

[jhs]

Thank you for this PR! Unfortunately, I am no longer a maintainer in this GitHub account, but I have merged your branch in my own fork, https://github.com/jhs/dnsd and I have included it in the v0.9.6 release.

[demmer]

Thanks for the quick turnaround. Will your fork be the authoritative repository for this package going forward in case I have other changes to suggest? I assume so given that you updated the npm metadata as such but I just wanted to be sure.

[jhs]

Yes, my fork is the official one. I started the project when I was in the iriscouch organization however I am no longer there. But I still maintain many of the projects here. I still have npm publish ability, which is the main thing.