Resolve an AT handle to it's DID record.
seoul.systems
at_lookup.ts
1/**
2 * @file AT Protocol handle resolver
3 * @description Resolves AT Protocol handles to DIDs using DNS TXT records
4 */
5
6import dns from "node:dns";
7import process from "node:process";
8
9const DOT = ".";
10
11/**
12 * The AT Protocol DNS TXT record prefix
13 * @see https://atproto.com/specs/handle#dns-txt-method
14 */
15const at_prefix = "_atproto";
16
17/**
18 * Callback function for DNS TXT record resolution
19 * @param {NodeJS.ErrnoException | null} err - Error object if resolution failed, null otherwise
20 * @param {string[][]} addresses - Array of TXT record values returned from DNS lookup
21 * @throws {NodeJS.ErrnoException} Throws the error if DNS resolution fails
22 */
23function resolveCb(err: NodeJS.ErrnoException | null, addresses: string[][]) {
24 if (err) {
25 throw err;
26 }
27
28 const address = addresses[0][0];
29 console.info(address);
30}
31
32const input = process.argv;
33
34if (input.length !== 3) {
35 throw new Error("Please provide a handle to resolve.");
36}
37
38const host = input.pop();
39
40/**
41 * Get the did record that corresponds to an internet handle
42 * see https://atproto.com/specs/handle#dns-txt-method
43 */
44dns.resolveTxt(at_prefix + DOT + host, resolveCb);