The HTTP protocol has a lot of header fields that affects requests and responses. HTTP also have a couple of different request types (HEAD, GET, POST, PUT and DELETE). Unless you’re building a REST service, you mostly have to deal with GET and POST on the web, and I don’t even differentiate those as much as I should. A couple of weeks ago, a thought occurred to me; ”What happens when I make a HEAD request to my blog?”. Well the answer turned out to be pretty simple. Node.js ignores any calls made to the write method of the response object if the request was a HEAD request. That’s all fine with me, but then I started thinking about what type of things should go into a HEAD response and if I could optimize anything. This lead me to look closer into the `Content-Length` header field. The `…