Writing a simple WHOIS client is more cursed than you think.

November 12, 2020

Seriously though.

I am known for writing cursed JavaScript applets but this one, went above my own charts.

So, lets glance over this curse.

        for (const line of dataLines) {
            // ignore comments, some use "%", some use "#"
            if (line.startsWith("%") || line.startsWith("#")) continue;
            // ignore empty lines
            if (line.length === 0 || line.match(/^\s+$/)) continue;
            // if line starts with one of below
            if (line.startsWith("refer:") || line.startsWith("whois:") || line.startsWith("ReferralServer:")) {
                // split line by spaces, ignore the first value (which is the value identifier), join spaces and strip beginning and end spaces
                let stripped = this.__strStrip(line.split(" ").slice(1).join(" "));
                // push the stripped one
                whoisServersRaw.push(stripped);
            }
            // uh, if this is a domain whois result, do some regex magic I cba explaining this
            if (this.__strStrip(line).match(/^\w+ WHOIS Server: /i)) {
                let strippassone = this.__strStrip(line).replace(/^\w+ WHOIS Server: /i, "");
                whoisServersRaw.push(strippassone);
            }
        }

        // well, rwhois not really whois
        for (const server of whoisServersRaw) {
            if (server.startsWith("rwhois://") || server.includes(":4321")) continue;
            whoisServers.push(server.replace("whois://", ""));
        }

WHOIS is a big free for all. Parsing the output for recursive WHOIS is not only important, but a whole other craftwork.

Now, that was referral parsing but uh; how do you even get the right encoded data?

Right, WHOIS doesn't specify an encoding. Luckily, whois(1) comes to rescue. So this became a thing:

                let encoding = (this.__extQuirks[host] ? this.__extQuirks[host].encoding : chardet.detect(data));
                return resolve(iconv.decode(data, encoding));

Then there's the conversion of event-driven Node.js TCP stack to async-await style calls.

Then, there was the simple web app. Well that was easier than the WHOIS client.

w.iye.be is a test instance for the code for new-iwhois.

The code is available at GitHub.