Use createHTTPSAgent for all requests

ts/textsecure/WebAPI.ts

@@ -1367,13 +1367,17 @@ export function initialize({
       log.warn(`${logId}: Done`);
     }
 
-    let fetchForLinkPreviews: linkPreviewFetch.FetchFn;
+    let fetchAgent: Agent;
     if (proxyUrl) {
-      const agent = createProxyAgent(proxyUrl);
-      fetchForLinkPreviews = (href, init) => fetch(href, { ...init, agent });
+      fetchAgent = createProxyAgent(proxyUrl);
     } else {
-      fetchForLinkPreviews = fetch;
+      fetchAgent = createHTTPSAgent({
+        keepAlive: false,
+        maxCachedSessions: 0,
+      });
     }
+    const fetchForLinkPreviews: linkPreviewFetch.FetchFn = (href, init) =>
+      fetch(href, { ...init, agent: fetchAgent });
 
     // Thanks, function hoisting!
     return {

ts/util/createHTTPSAgent.ts

@@ -33,6 +33,28 @@ const CONNECT_TIMEOUT_MS = 10 * SECOND;
 
 const electronLookup = promisify(electronLookupWithCb);
 
+const HOST_LOG_ALLOWLIST = new Set([
+  // Production
+  'chat.signal.org',
+  'storage.signal.org',
+  'cdsi.signal.org',
+  'cdn.signal.org',
+  'cdn2.signal.org',
+  'create.signal.art',
+
+  // Staging
+  'chat.staging.signal.org',
+  'storage-staging.signal.org',
+  'cdsi.staging.signal.org',
+  'cdn-staging.signal.org',
+  'cdn2-staging.signal.org',
+  'create.staging.signal.art',
+
+  // Common
+  'updates2.signal.org',
+  'sfu.voip.signal.org',
+]);
+
 export class Agent extends HTTPSAgent {
   constructor(options: AgentOptions = {}) {
     super({
@@ -65,16 +87,18 @@ export class Agent extends HTTPSAgent {
         },
       });
 
-      const duration = Date.now() - start;
-      const logLine =
-        `createHTTPSAgent.createConnection(${host}): connected to ` +
-        `IPv${address.family} addr after ${duration}ms ` +
-        `(attempts v4=${v4Attempts} v6=${v6Attempts})`;
+      if (HOST_LOG_ALLOWLIST.has(host)) {
+        const duration = Date.now() - start;
+        const logLine =
+          `createHTTPSAgent.createConnection(${host}): connected to ` +
+          `IPv${address.family} addr after ${duration}ms ` +
+          `(attempts v4=${v4Attempts} v6=${v6Attempts})`;
 
-      if (v4Attempts + v6Attempts > 1 || duration > CONNECT_THRESHOLD_MS) {
-        log.warn(logLine);
-      } else {
-        log.info(logLine);
+        if (v4Attempts + v6Attempts > 1 || duration > CONNECT_THRESHOLD_MS) {
+          log.warn(logLine);
+        } else {
+          log.info(logLine);
+        }
       }
 
       return socket;

ts/util/dns.ts

@@ -1,36 +1,18 @@
 // Copyright 2023 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-import type { LookupOneOptions, LookupAllOptions, LookupAddress } from 'dns';
-import { lookup as nodeLookup } from 'dns';
+import type {
+  LookupOneOptions,
+  LookupAllOptions,
+  LookupAddress,
+  lookup as nodeLookup,
+} from 'dns';
 import { ipcRenderer, net } from 'electron';
 import type { ResolvedHost } from 'electron';
 
 import { strictAssert } from './assert';
 import { drop } from './drop';
 
-const HOST_ALLOWLIST = new Set([
-  // Production
-  'chat.signal.org',
-  'storage.signal.org',
-  'cdsi.signal.org',
-  'cdn.signal.org',
-  'cdn2.signal.org',
-  'create.signal.art',
-
-  // Staging
-  'chat.staging.signal.org',
-  'storage-staging.signal.org',
-  'cdsi.staging.signal.org',
-  'cdn-staging.signal.org',
-  'cdn2-staging.signal.org',
-  'create.staging.signal.art',
-
-  // Common
-  'updates2.signal.org',
-  'sfu.voip.signal.org',
-]);
-
 function lookupAll(
   hostname: string,
   opts: LookupOneOptions | LookupAllOptions,
@@ -40,11 +22,6 @@ function lookupAll(
     family?: number
   ) => void
 ): void {
-  if (!HOST_ALLOWLIST.has(hostname)) {
-    nodeLookup(hostname, opts, callback);
-    return;
-  }
-
   // Node.js support various signatures, but we only support one.
   strictAssert(typeof opts === 'object', 'missing options');
   strictAssert(typeof callback === 'function', 'missing callback');