Connect 1.7.0 - fast static file memory cache and more

Be sure to update Connect to the latest release 1.7.0 for the following goodies!

staticCache() middleware

1.7.0 now provides a new middleware named staticCache(), acting as a memory cache on top of the regular static() middleware. Older versions of Connect used to provide memory caching, however it was baked right into static(), bloating the middleware more than necessary.

Benchmarks

The test file for these benchmarks is a small 4kb readme:

$ du -h Readme.md 
4.0K    Readme.md

and the following ApacheBench command:

$ ab -n 5000 -c 50 -k http://local/Readme.md

First up we have Connect static(), which does not perform any caching, performing disk I/O each request, serving ~2400rps.

connect()
  .use(connect.static(__dirname))
  .listen(3000)

Next up we have node-static one of the other popular node solutions, serving ~3800rps

var static = require('node-static')
  , file = new static.Server(__dirname);

http.createServer(function(req, res){
  file.serve(req, res);
}).listen(3000);

Then we have the new staticCache() middleware paired with static() serving ~5000rps, a 24% increase over node-static (which also performs memory caching), and ~52% over static() alone.

connect()
  .use(connect.staticCache())
  .use(connect.static(__dirname))
  .listen(3000)

staticCache() is configurable, allowing you to specify the maximum number of cache objects to store, and the maximum size allowed, so you can cap resources appropriately. The middleware implements a Least Recently Used algorithm to prioritize popular files, knocking less popular objects out of the cache.

res.headerSent

Node core has a private flag named res._headerSent, allowing you to check if the header has been written or not, this is extremely useful in some cases, so Connect has publicized this property as res.headerSent until Node core does (if ever), using a getter to reference the private property.

logger() immediate option

The logger() middleware now provides { immediate: true }, as by default this middleware will log the response of a request, not when the request is first received, allowing logging of response-times etc.