When you have a single webserver with multiple nodejs applications, the typical thing you do is slap some reverse proxy in front of them all and write rules. Nginx is currently a favorite because it's fast, so I'll focus on that, but the question can also be applied to other webservers.
It struck me today that it sounds a bit inefficient. After all, the same HTTP request needs to be parsed twice - first by the proxy, then by nodejs. And the protocol itself is also text based with plenty of edge cases in the parser... couldn't the coupling between the webserver and nodejs be made more efficient so that the request needs to be parsed only once?
My first idea was about fastcgi, but it turns out that just makes things worse because it limits nodejs to processing one request at a time. And anyway it's pretty dated.
Then I dug a bit more and found SCGI which seems even better and is even supported by nginx... but not on the NodeJs side, it seems.
And lastly I found Apache JServ protocol but support is even worse with neither nginx nor nodejs supporting it as far as I can tell.
Why is this? I understand that this overhead is probably small compared to everything else that happens in a typical request, but is it really so insignificant that it's not even worth putting any effort into it? Even small gains can add up, and there could easily be a simple package that replaces Node's http.Server with a compatible scgi.Server with minimum effort.