From 8b5583e08ece79e819b6f7ec43efcd96864a7bdd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Muhammed=20Tanr=C4=B1kulu?= <md.tanrikulu@gmail.com>
Date: Mon, 15 Apr 2024 18:26:36 +0200
Subject: [PATCH] add txt record extract util, update logger for latest
 server-analytics changes

---
 src/utils.ts  | 39 +++++++++++++++++++++++++++++++++++++++
 src/worker.ts | 46 +++++++++++++++++++++++++---------------------
 2 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index 6231de4..cf90da7 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -11,3 +11,42 @@ export function serializeError(error: any) {
     return JSON.stringify(error);
   }
 }
+
+type DNSRecord = {
+  rrset: string;
+  sig: string;
+};
+
+function hexToAscii(hex: string): string {
+  let result = '';
+  for (let i = 0; i < hex.length; i += 2) {
+    const part = parseInt(hex.substring(i, i + 2), 16);
+    if (part) result += String.fromCharCode(part);
+  }
+  return result;
+}
+
+export function extractENSRecord(dnsRecords: DNSRecord[]): string[] {
+  const txtPrefix = '0x0010'; // 16
+  const txtRecords: string[] = [];
+
+  for (const record of dnsRecords) {
+    if (record.rrset.startsWith(txtPrefix)) {
+      const contentStart = txtPrefix.length;
+      const rawContent = record.rrset.slice(contentStart);
+      let asciiContent = hexToAscii(rawContent);
+
+      asciiContent = asciiContent.split('\t').join();
+
+      const parts = asciiContent.split(',');
+      for (const part of parts) {
+        if (part.includes('ENS1')) {
+          txtRecords.push(part.slice(2));
+        }
+      }
+    }
+  }
+
+  return txtRecords;
+}
+
diff --git a/src/worker.ts b/src/worker.ts
index 7f7ebd7..349ea80 100644
--- a/src/worker.ts
+++ b/src/worker.ts
@@ -5,13 +5,25 @@ import {
 import { Server } from '@ensdomains/ccip-read-cf-worker';
 import { Tracker } from '@ensdomains/server-analytics';
 import { dohQuery } from '@ensdomains/dnsprovejs';
+import { ethers } from 'ethers';
 import { makeApp } from './app';
+import { extractENSRecord } from './utils';
 
 interface ENV {
   DOH_GATEWAY_URL: string;
   PLAUSIBLE_BASE_URL: string;
 }
 
+const abi_RRSetWithSignature = [
+  ethers.utils.ParamType.from({
+    components: [
+      { type: 'bytes', name: 'rrset' },
+      { type: 'bytes', name: 'sig' },
+    ],
+    type: 'tuple[]',
+  }),
+];
+
 const tracker = new Tracker('ccip-read-dns-worker.ens-cf.workers.dev', {
   enableLogging: true,
 });
@@ -28,26 +40,16 @@ const routeHandler = (env: ENV, trackEvent?: Function) => {
   return app;
 };
 
-const logResult = async (request: CFWRequest, result: Response) => {
-  if (!result.body) {
-    return result;
-  }
-  const [streamForLog, streamForResult] = result.body.tee();
-  try {
-    const resultForLog: { data: string } = await new Response(
-      streamForLog
-    ).json();
-
-    await tracker.trackEvent(
-      request,
-      'result',
-      { props: { result: resultForLog.data.substring(0, 200) } },
-      true
-    );
-  } catch (error) {
-    console.log('error logging result:', error);
-  }
-  return new Response(streamForResult, result);
+const dataDecoder = async (data: string) => {
+  const decodedData = ethers.utils.defaultAbiCoder.decode(
+    abi_RRSetWithSignature,
+    data
+  )[0];
+  const structuredData = decodedData.map((item: string[]) => ({
+    rrset: item[0],
+    sig: item[1],
+  }));
+  return extractENSRecord(structuredData);
 };
 
 module.exports = {
@@ -62,6 +64,8 @@ module.exports = {
     await tracker.trackEvent(request, 'request', {}, true);
     await tracker.trackPageview(request, {}, true);
     const router = routeHandler(env, tracker.trackEvent.bind(tracker, request));
-    return router.handle(request).then(logResult.bind(this, request));
+    return router
+      .handle(request)
+      .then(tracker.logResult.bind(this, request, dataDecoder));
   },
 };