pipic/server/server.js

var fs = require("fs");
var http = require("http");
var crypto = require("crypto");

function Pic(path) {
	var content = fs.readFileSync(path);
	var hash = crypto.createHash("sha1").update(content).digest("hex");

	var self = {
		path: path,
		hash: hash,
		content: content
	}

	return self;
}

var currentPic = Pic("/home/martin/background.jpg");

http.createServer((req, res) => {
	var hash = req.url.substring(1); // Remove the first / to get only hash
	console.log("got hash "+hash+", existing hash is "+currentPic.hash);

	if (hash === currentPic.hash) {
		res.end();
	} else {
		res.end(currentPic.content);
	}
}).listen(8080);