From 1ce00bd3b6909f78f212a7a172cf845b55280599 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@alhur.es>
Date: Mon, 19 Jul 2021 08:28:14 -0300
Subject: [PATCH] nip05.

---
 nip05.js     | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 package.json |  3 ++-
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 nip05.js

diff --git a/nip05.js b/nip05.js
new file mode 100644
index 0000000..39d2986
--- /dev/null
+++ b/nip05.js
@@ -0,0 +1,51 @@
+import dnsPacket from 'dns-packet'
+
+const dohProviders = [
+  'cloudflare-dns.com',
+  'fi.doh.dns.snopyta.org',
+  'basic.bravedns.com',
+  'hydra.plan9-ns1.com',
+  'doh.pl.ahadns.net',
+  'dns.flatuslifir.is',
+  'doh.dns.sb',
+  'doh.li'
+]
+
+let counter = 0
+
+export async function keyFromDomain(domain) {
+  let host = dohProviders[counter % dohProviders.length]
+
+  let buf = dnsPacket.encode({
+    type: 'query',
+    id: Math.floor(Math.random() * 65534),
+    flags: dnsPacket.RECURSION_DESIRED,
+    questions: [
+      {
+        type: 'TXT',
+        name: `_nostrkey.${domain}`
+      }
+    ]
+  })
+
+  let fetching = fetch(`https://${host}/dns-query`, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/dns-message',
+      'Content-Length': Buffer.byteLength(buf)
+    },
+    body: buf
+  })
+
+  counter++
+
+  try {
+    let response = Buffer.from(await (await fetching).arrayBuffer())
+    let {answers} = dnsPacket.decode(response)
+    if (answers.length === 0) return null
+    return Buffer.from(answers[0].data[0]).toString()
+  } catch (err) {
+    console.log(`error querying DNS for ${domain} on ${host}`, err)
+    return null
+  }
+}
diff --git a/package.json b/package.json
index 6513283..24eea1d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "nostr-tools",
-  "version": "0.4.6",
+  "version": "0.5.0",
   "description": "Tools for making a Nostr client.",
   "main": "index.js",
   "repository": {
@@ -9,6 +9,7 @@
   },
   "dependencies": {
     "buffer": "^6.0.3",
+    "dns-packet": "^5.2.4",
     "noble-secp256k1": "^1.1.1",
     "websocket-polyfill": "^0.0.3"
   },