From 4d39385b91ec91e07a8611522e513f5b4ca12517 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 17:09:21 +0300
Subject: [PATCH 01/18] support `options.prefer_ipv6` and use `ipv6first` for
 it

---
 lib/fetch.js | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index b7f29f8dd..0d368689c 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -1,4 +1,5 @@
 import { URL } from 'url';
+import dns from 'node:dns';
 import { h1NoCache, noCache, createUrl, AbortController, AbortError, FetchError } from '@adobe/fetch';
 import { serialize as serializeCookie, parse as parseCookie } from 'cookie';
 import log from '../logging.js';
@@ -38,6 +39,28 @@ const fetchH1 = h1NoCache({
     rejectUnauthorized: false   // By default skip auth check for all.
 }).fetch;
 
+// Sorts AAAA first for this context only; autoSelectFamily falls back to IPv4 on connect failure. Requires Node >= 20.13.
+const lookupIPv6First = (hostname, options, callback) =>
+    dns.lookup(hostname, { ...options, order: 'ipv6first' }, callback);
+
+const fetchIPv6First = noCache({
+    h1: {
+        lookup: lookupIPv6First
+    },
+    h2: {
+        enablePush: false,
+        lookup: lookupIPv6First
+    },
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+
+const fetchH1IPv6First = h1NoCache({
+    h1: {
+        lookup: lookupIPv6First
+    },
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+
 export function skipLoggingFetchError(error) {
     return error?.name === 'AbortError' 
         || error?.code === 'ECONNRESET'
@@ -49,6 +72,13 @@ export function skipLoggingFetchError(error) {
         || error?.code === 'ETIMEDOUT';
 }
 
+function selectFetchFunc(options, fetch_func = fetch, h1_fetch_func = fetchH1) {
+    if (options.prefer_ipv6) {
+        return options.disable_http2 ? fetchH1IPv6First : fetchIPv6First;
+    }
+    return options.disable_http2 ? h1_fetch_func : fetch_func;
+}
+
 function doFetch(fetch_func, h1_fetch_func, options) {
     
     const fetch_options = Object.assign({}, options);
@@ -73,7 +103,7 @@ function doFetch(fetch_func, h1_fetch_func, options) {
         abortController.abort();
     }, options.timeout || CONFIG.RESPONSE_TIMEOUT);
 
-    const a_fetch_func = options.disable_http2 ? h1_fetch_func: fetch_func;
+    const a_fetch_func = selectFetchFunc(options, fetch_func, h1_fetch_func);
     return new Promise((resolve, reject) => {
         a_fetch_func(uri, fetch_options)
             .then(response => {
@@ -184,7 +214,7 @@ export function fetchData(options) {
         abortController.abort();
     }, options.timeout || CONFIG.RESPONSE_TIMEOUT);
 
-    const a_fetch_func = options.disable_http2 ? fetchH1: fetch;
+    const a_fetch_func = selectFetchFunc(options);
     return new Promise((resolve, reject) => {
         a_fetch_func(uri, fetch_options)
             .then(response => {

From e0e22300c001b8b88858167b83f9af69f94f4c42 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 17:11:36 +0300
Subject: [PATCH 02/18] read `prefer_ipv6` from proxy config

---
 lib/utils.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/utils.js b/lib/utils.js
index 6a80e9ade..071dc8914 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -153,6 +153,9 @@ export function prepareRequestOptions(request_options, options) {
                     if (proxy.disable_http2) {
                         request_options.disable_http2 = true;
                     }
+                    if (proxy.prefer_ipv6) {
+                        request_options.prefer_ipv6 = true;
+                    }
                     if (proxy.disable_language) {
                         disable_language = true;
                     }

From 20a42897f3b94f973b72dd2225d961c44befa94a Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 17:13:31 +0300
Subject: [PATCH 03/18] debug ipv6 lookup

---
 lib/fetch.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 0d368689c..0ed254165 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -41,7 +41,17 @@ const fetchH1 = h1NoCache({
 
 // Sorts AAAA first for this context only; autoSelectFamily falls back to IPv4 on connect failure. Requires Node >= 20.13.
 const lookupIPv6First = (hostname, options, callback) =>
-    dns.lookup(hostname, { ...options, order: 'ipv6first' }, callback);
+    dns.lookup(hostname, { ...options, order: 'ipv6first' }, (error, address, family) => {
+        if (error) {
+            log('   -- lookupIPv6First error', hostname, error.code, error.message);
+        } else if (Array.isArray(address)) {
+            // With autoSelectFamily lookup is called with `all: true`.
+            log('   -- lookupIPv6First', hostname, address.map(a => `${a.address} (v${a.family})`).join(', '));
+        } else {
+            log('   -- lookupIPv6First', hostname, `${address} (v${family})`);
+        }
+        callback(error, address, family);
+    });
 
 const fetchIPv6First = noCache({
     h1: {

From e2593b32909d9d3fe9d24dfc2c9b5e0b79b1ca39 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 17:20:31 +0300
Subject: [PATCH 04/18] comment

---
 lib/fetch.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/fetch.js b/lib/fetch.js
index 0ed254165..3c09cf36d 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -189,6 +189,7 @@ function doFetch(fetch_func, h1_fetch_func, options) {
 }
 
 export function fetchStreamKeepAlive(options) {
+    // TODO: ipv6 priority?
     return doFetch(fetchKeepAlive, fetchH1KeepAlive, options);
 }
 
@@ -197,6 +198,7 @@ export function fetchStream(options) {
 };
 
 export function fetchStreamAuthorized(options) {
+    // TODO: ipv6 priority?
     return doFetch(fetchAuthorized, fetchH1Authorized, options);
 };
 

From cff484abb3cec3e9c324829163c480cd92669c8d Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 18:11:56 +0300
Subject: [PATCH 05/18] patch `@adobe/fetch` to support custom agent dns lookup

---
 patches/@adobe__fetch.patch | 21 +++++++++++++++++++++
 pnpm-lock.yaml              |  5 +++--
 pnpm-workspace.yaml         |  1 +
 3 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 patches/@adobe__fetch.patch

diff --git a/patches/@adobe__fetch.patch b/patches/@adobe__fetch.patch
new file mode 100644
index 000000000..a57987b1c
--- /dev/null
+++ b/patches/@adobe__fetch.patch
@@ -0,0 +1,21 @@
+diff --git a/src/core/request.js b/src/core/request.js
+index 6f7120e3e383ed44b4fe63861109f365579d7425..19de7a26bc712e172b78efb4de4ef97ad8f269e3 100644
+--- a/src/core/request.js
++++ b/src/core/request.js
+@@ -160,7 +160,16 @@ const determineProtocol = async (ctx, url, signal) => {
+   const rejectUnauthorized = !((_rejectUnauthorized === false
+     || h1Opts.rejectUnauthorized === false
+     || h2Opts.rejectUnauthorized === false));
++  // PATCH: forward DNS/socket options from context to the ALPN negotiation socket
++  const socketOptions = {};
++  ['lookup', 'family', 'autoSelectFamily', 'autoSelectFamilyAttemptTimeout'].forEach((name) => {
++    const value = h2Opts[name] !== undefined ? h2Opts[name] : h1Opts[name];
++    if (value !== undefined) {
++      socketOptions[name] = value;
++    }
++  });
+   const connectOptions = {
++    ...socketOptions,
+     servername: url.hostname, // enable SNI (Server Name Indication) extension
+     ALPNProtocols: ctx.alpnProtocols,
+     signal, // optional abort signal
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5acafc28a..d3dce785f 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -32,6 +32,7 @@ overrides:
   proxy-addr@>=1.1.0 <2.0.8: ^2.0.8
 
 patchedDependencies:
+  '@adobe/fetch': fe94317880319fddf09a3d0f8eda551d5a2a205441bf5a7d634005239702b38d
   readabilitySAX@1.6.1: 13d40f78c0537e2538fd3a338f5ead833d968e2a80882e92f1eb3580b599c757
 
 importers:
@@ -40,7 +41,7 @@ importers:
     dependencies:
       '@adobe/fetch':
         specifier: ^4.1.11
-        version: 4.1.11(supports-color@8.1.1)
+        version: 4.1.11(patch_hash=fe94317880319fddf09a3d0f8eda551d5a2a205441bf5a7d634005239702b38d)(supports-color@8.1.1)
       async:
         specifier: ^3.2.4
         version: 3.2.4
@@ -1376,7 +1377,7 @@ packages:
 
 snapshots:
 
-  '@adobe/fetch@4.1.11(supports-color@8.1.1)':
+  '@adobe/fetch@4.1.11(patch_hash=fe94317880319fddf09a3d0f8eda551d5a2a205441bf5a7d634005239702b38d)(supports-color@8.1.1)':
     dependencies:
       debug: 4.4.0(supports-color@8.1.1)
       http-cache-semantics: 4.3.0
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index c385fbc06..66711fa27 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -25,4 +25,5 @@ overrides:
   probe-image-size@<=7.3.0: ^7.4.0
   proxy-addr@>=1.1.0 <2.0.8: ^2.0.8
 patchedDependencies:
+  '@adobe/fetch': patches/@adobe__fetch.patch
   readabilitySAX@1.6.1: patches/readabilitySAX@1.6.1.patch

From 3bf3eaed9f3612dd4a2dce0c82a812837ec917b3 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 18:12:31 +0300
Subject: [PATCH 06/18] debug log

---
 lib/fetch.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 3c09cf36d..61da1f818 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -40,7 +40,8 @@ const fetchH1 = h1NoCache({
 }).fetch;
 
 // Sorts AAAA first for this context only; autoSelectFamily falls back to IPv4 on connect failure. Requires Node >= 20.13.
-const lookupIPv6First = (hostname, options, callback) =>
+const lookupIPv6First = (hostname, options, callback) => {
+    log(' -- lookupIPv6First start', hostname);
     dns.lookup(hostname, { ...options, order: 'ipv6first' }, (error, address, family) => {
         if (error) {
             log('   -- lookupIPv6First error', hostname, error.code, error.message);
@@ -52,6 +53,7 @@ const lookupIPv6First = (hostname, options, callback) =>
         }
         callback(error, address, family);
     });
+}
 
 const fetchIPv6First = noCache({
     h1: {

From 5fd23175075dd0bbc9815b2229b871f21a5016b4 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 19:05:22 +0300
Subject: [PATCH 07/18] allow set `prefer_ipv6` from main options

---
 lib/utils.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/utils.js b/lib/utils.js
index 071dc8914..c45b918ba 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -171,6 +171,10 @@ export function prepareRequestOptions(request_options, options) {
                 }
             }
 
+            if (options?.prefer_ipv6) {
+                request_options.prefer_ipv6 = true;
+            }
+
             if (options?.user_agent) {
                 // Let `options.user_agent` be prioritized over `proxy.user_agent`.
                 request_options.headers['User-Agent'] = options?.user_agent;

From ad4b8c4560bb2ff6c6e7124505e2e72c8084ec78 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 19:40:44 +0300
Subject: [PATCH 08/18] optimize different fetch cases as cached profiles by
 key

---
 lib/fetch.js | 124 +++++++++++++++++++++------------------------------
 1 file changed, 50 insertions(+), 74 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 61da1f818..773e72a09 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -4,74 +4,48 @@ import { h1NoCache, noCache, createUrl, AbortController, AbortError, FetchError
 import { serialize as serializeCookie, parse as parseCookie } from 'cookie';
 import log from '../logging.js';
 
-const fetchKeepAlive = noCache({
-    h1: {
-        keepAlive: true
-    },
-    h2: {
-        enablePush: false
-    },
-    rejectUnauthorized: false   // By default skip auth check for all.
-}).fetch;
-
-const fetchH1KeepAlive = h1NoCache({
-    h1: {
-        keepAlive: true
-    },
-    rejectUnauthorized: false   // By default skip auth check for all.
-}).fetch;
-
-const fetchAuthorized = noCache({
-    h2: {
-        enablePush: false
-    }
-}).fetch;    // `rejectUnauthorized: true` - by `fetch` default.
-const fetchH1Authorized = h1NoCache().fetch;      // `rejectUnauthorized: true` - by `fetch` default.
-
-const { fetch } = noCache({
-    h2: {
-        enablePush: false
-    },
-    rejectUnauthorized: false   // By default skip auth check for all.
-});
-
-const fetchH1 = h1NoCache({
-    rejectUnauthorized: false   // By default skip auth check for all.
-}).fetch;
-
-// Sorts AAAA first for this context only; autoSelectFamily falls back to IPv4 on connect failure. Requires Node >= 20.13.
-const lookupIPv6First = (hostname, options, callback) => {
-    log(' -- lookupIPv6First start', hostname);
-    dns.lookup(hostname, { ...options, order: 'ipv6first' }, (error, address, family) => {
+const makeLookup = (order) => (hostname, options, callback) =>
+    dns.lookup(hostname, { ...options, order }, (error, address, family) => {
         if (error) {
-            log('   -- lookupIPv6First error', hostname, error.code, error.message);
+            log(`   -- lookup ${order} error`, hostname, error.code, error.message);
         } else if (Array.isArray(address)) {
             // With autoSelectFamily lookup is called with `all: true`.
-            log('   -- lookupIPv6First', hostname, address.map(a => `${a.address} (v${a.family})`).join(', '));
+            log(`   -- lookup ${order}`, hostname, address.map(a => `${a.address} (v${a.family})`).join(', '));
         } else {
-            log('   -- lookupIPv6First', hostname, `${address} (v${family})`);
+            log(`   -- lookup ${order}`, hostname, `${address} (v${family})`);
         }
         callback(error, address, family);
     });
-}
 
-const fetchIPv6First = noCache({
-    h1: {
-        lookup: lookupIPv6First
-    },
-    h2: {
-        enablePush: false,
-        lookup: lookupIPv6First
-    },
-    rejectUnauthorized: false   // By default skip auth check for all.
-}).fetch;
-
-const fetchH1IPv6First = h1NoCache({
-    h1: {
-        lookup: lookupIPv6First
-    },
-    rejectUnauthorized: false   // By default skip auth check for all.
-}).fetch;
+// `ipv6first` order requires Node >= 20.13. autoSelectFamily falls back to the other family on connect failure.
+const LOOKUPS = {
+    default: undefined,     // Node's global resolver order.
+    ipv6first: makeLookup('ipv6first'),
+    ipv4first: makeLookup('ipv4first')
+};
+
+const PROFILES = {
+    default:    { rejectUnauthorized: false },   // By default skip auth check for all.
+    keepAlive:  { rejectUnauthorized: false, h1: { keepAlive: true } },
+    authorized: {}                               // `rejectUnauthorized: true` - by `fetch` default.
+};
+
+// Lazily created fetch contexts, memoized per profile/protocol/dns order combination.
+const fetchFuncs = {};
+
+function getFetchFunc(profile, proto, order) {
+    const key = `${profile}:${proto}:${order}`;
+    if (!fetchFuncs[key]) {
+        const profileOpts = PROFILES[profile];
+        const lookup = LOOKUPS[order];
+        const h1 = { ...profileOpts.h1, ...(lookup && { lookup }) };
+        const h2 = { enablePush: false, ...(lookup && { lookup }) };
+        fetchFuncs[key] = proto === 'h1'
+            ? h1NoCache({ ...profileOpts, h1 }).fetch
+            : noCache({ ...profileOpts, h1, h2 }).fetch;
+    }
+    return fetchFuncs[key];
+}
 
 export function skipLoggingFetchError(error) {
     return error?.name === 'AbortError' 
@@ -84,14 +58,18 @@ export function skipLoggingFetchError(error) {
         || error?.code === 'ETIMEDOUT';
 }
 
-function selectFetchFunc(options, fetch_func = fetch, h1_fetch_func = fetchH1) {
+function selectFetchFunc(options, profile = 'default') {
+    let order = 'default';
     if (options.prefer_ipv6) {
-        return options.disable_http2 ? fetchH1IPv6First : fetchIPv6First;
+        order = 'ipv6first'
+    }
+    if (options.prefer_ipv4) {
+        order = 'ipv4first'
     }
-    return options.disable_http2 ? h1_fetch_func : fetch_func;
+    return getFetchFunc(profile, options.disable_http2 ? 'h1' : 'h2', order);
 }
 
-function doFetch(fetch_func, h1_fetch_func, options) {
+function doFetch(profile, options) {
     
     const fetch_options = Object.assign({}, options);
     const is_head_request = fetch_options.method === 'HEAD';
@@ -115,7 +93,7 @@ function doFetch(fetch_func, h1_fetch_func, options) {
         abortController.abort();
     }, options.timeout || CONFIG.RESPONSE_TIMEOUT);
 
-    const a_fetch_func = selectFetchFunc(options, fetch_func, h1_fetch_func);
+    const a_fetch_func = selectFetchFunc(options, profile);
     return new Promise((resolve, reject) => {
         a_fetch_func(uri, fetch_options)
             .then(response => {
@@ -141,7 +119,7 @@ function doFetch(fetch_func, h1_fetch_func, options) {
                     && CONFIG.DISABLE_HTTP2_CHECKS?.some(check => typeof check === 'function'
                                                                 && check(response.status, headers))) {
                     log('   -- doFetch check disabled h2', uri);
-                    resolve(doFetch(fetch_func, h1_fetch_func, Object.assign({}, options, {disable_http2: true})));
+                    resolve(doFetch(profile, Object.assign({}, options, {disable_http2: true})));
                 } else {
                     stream.status = response.status;
                     if (response.url && response.url !== uri) { // Set as final destination url if Fetch follows 301/302 re-directs
@@ -162,7 +140,7 @@ function doFetch(fetch_func, h1_fetch_func, options) {
                 if (!options.disable_http2 && error.code && /^ERR_HTTP2/.test(error.code)) {
 
                     log('   -- doFetch http2 error', error.code, uri);
-                    resolve(doFetch(fetch_func, h1_fetch_func, Object.assign({}, options, {disable_http2: true})));
+                    resolve(doFetch(profile, Object.assign({}, options, {disable_http2: true})));
 
                 } else if (!options.disable_http2 && error.code && error instanceof FetchError && error.code === 'ABORT_ERR') {
 
@@ -172,12 +150,12 @@ function doFetch(fetch_func, h1_fetch_func, options) {
                      * https://app.everviz.com/show/O0Cy7Dyt
                      */
                     log('   -- doFetch h2 aborted error', uri);
-                    resolve(doFetch(fetch_func, h1_fetch_func, Object.assign({}, options, {disable_http2: true})));
+                    resolve(doFetch(profile, Object.assign({}, options, {disable_http2: true})));
 
                 } else if (!options.stopRecursion && CONFIG.ERRORS_TO_RETRY?.some(code => error.code?.indexOf(code) > -1)) {
 
                     log('   -- doFetch ECONNRESET retry', error.code, uri);
-                    resolve(doFetch(fetch_func, h1_fetch_func, Object.assign({}, options, {stopRecursion: true, disable_http2: true})));
+                    resolve(doFetch(profile, Object.assign({}, options, {stopRecursion: true, disable_http2: true})));
 
                 } else {
                     if (error instanceof AbortError) {
@@ -191,17 +169,15 @@ function doFetch(fetch_func, h1_fetch_func, options) {
 }
 
 export function fetchStreamKeepAlive(options) {
-    // TODO: ipv6 priority?
-    return doFetch(fetchKeepAlive, fetchH1KeepAlive, options);
+    return doFetch('keepAlive', options);
 }
 
 export function fetchStream(options) {
-    return doFetch(fetch, fetchH1, options);
+    return doFetch('default', options);
 };
 
 export function fetchStreamAuthorized(options) {
-    // TODO: ipv6 priority?
-    return doFetch(fetchAuthorized, fetchH1Authorized, options);
+    return doFetch('authorized', options);
 };
 
 export function fetchData(options) {

From b45c95535de7bbebbffb762c915b0a24cbd40bbb Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 19:45:57 +0300
Subject: [PATCH 09/18] rename `prefer_ipv6` to `ipv6first`

---
 lib/fetch.js | 8 ++++----
 lib/utils.js | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 773e72a09..c39e7252b 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -60,11 +60,11 @@ export function skipLoggingFetchError(error) {
 
 function selectFetchFunc(options, profile = 'default') {
     let order = 'default';
-    if (options.prefer_ipv6) {
-        order = 'ipv6first'
+    if (options.ipv6first) {
+        order = 'ipv6first';
     }
-    if (options.prefer_ipv4) {
-        order = 'ipv4first'
+    if (options.ipv4first) {
+        order = 'ipv4first';
     }
     return getFetchFunc(profile, options.disable_http2 ? 'h1' : 'h2', order);
 }
diff --git a/lib/utils.js b/lib/utils.js
index c45b918ba..0ca748d7a 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -153,8 +153,8 @@ export function prepareRequestOptions(request_options, options) {
                     if (proxy.disable_http2) {
                         request_options.disable_http2 = true;
                     }
-                    if (proxy.prefer_ipv6) {
-                        request_options.prefer_ipv6 = true;
+                    if (proxy.ipv6first) {
+                        request_options.ipv6first = true;
                     }
                     if (proxy.disable_language) {
                         disable_language = true;
@@ -171,8 +171,8 @@ export function prepareRequestOptions(request_options, options) {
                 }
             }
 
-            if (options?.prefer_ipv6) {
-                request_options.prefer_ipv6 = true;
+            if (options?.ipv6first) {
+                request_options.ipv6first = true;
             }
 
             if (options?.user_agent) {

From ca71efe9e1204155dba1a6e5815eb3a6b2c97a54 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 19:53:59 +0300
Subject: [PATCH 10/18] comment

---
 lib/fetch.js | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/lib/fetch.js b/lib/fetch.js
index c39e7252b..1972ee90b 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -32,6 +32,46 @@ const PROFILES = {
 
 // Lazily created fetch contexts, memoized per profile/protocol/dns order combination.
 const fetchFuncs = {};
+/*
+Generates fetches like:
+
+const fetchKeepAlive = noCache({
+    h1: {
+        keepAlive: true
+    },
+    h2: {
+        enablePush: false
+    },
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+
+const fetchH1KeepAlive = h1NoCache({
+    h1: {
+        keepAlive: true
+    },
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+
+const fetchAuthorized = noCache({
+    h2: {
+        enablePush: false
+    }
+}).fetch;                       // `rejectUnauthorized: true` - by `fetch` default.
+
+const fetchH1Authorized = h1NoCache().fetch;      
+                                // `rejectUnauthorized: true` - by `fetch` default.
+
+const fetch = noCache({
+    h2: {
+        enablePush: false
+    },
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+
+const fetchH1 = h1NoCache({
+    rejectUnauthorized: false   // By default skip auth check for all.
+}).fetch;
+*/
 
 function getFetchFunc(profile, proto, order) {
     const key = `${profile}:${proto}:${order}`;

From e59dcbd1ec5bb5f66bb0d890326a25153ec0fb61 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 20:03:02 +0300
Subject: [PATCH 11/18] make code nicer

---
 lib/fetch.js | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 1972ee90b..cce71b7a0 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -20,14 +20,27 @@ const makeLookup = (order) => (hostname, options, callback) =>
 // `ipv6first` order requires Node >= 20.13. autoSelectFamily falls back to the other family on connect failure.
 const LOOKUPS = {
     default: undefined,     // Node's global resolver order.
-    ipv6first: makeLookup('ipv6first'),
-    ipv4first: makeLookup('ipv4first')
+    ipv6first: { lookup: makeLookup('ipv6first') },
+    ipv4first: { lookup: makeLookup('ipv4first') }
 };
 
+const PROFILE_DEFAULT = 'default';
+const PROFILE_KEEP_ALIVE = 'keepAlive';
+const PROFILE_AUTHORIZED = 'authorized';
+
 const PROFILES = {
-    default:    { rejectUnauthorized: false },   // By default skip auth check for all.
-    keepAlive:  { rejectUnauthorized: false, h1: { keepAlive: true } },
-    authorized: {}                               // `rejectUnauthorized: true` - by `fetch` default.
+    [PROFILE_DEFAULT]:    {
+        rejectUnauthorized: false,  // By default skip auth check for all.
+        h2: { enablePush: false }
+    },
+    [PROFILE_KEEP_ALIVE]: {
+        rejectUnauthorized: false,
+        h1: { keepAlive: true },
+        h2: { enablePush: false }
+    },
+    [PROFILE_AUTHORIZED]: {         // `rejectUnauthorized: true` - by `fetch` default.
+        h2: { enablePush: false }
+    }
 };
 
 // Lazily created fetch contexts, memoized per profile/protocol/dns order combination.
@@ -78,8 +91,8 @@ function getFetchFunc(profile, proto, order) {
     if (!fetchFuncs[key]) {
         const profileOpts = PROFILES[profile];
         const lookup = LOOKUPS[order];
-        const h1 = { ...profileOpts.h1, ...(lookup && { lookup }) };
-        const h2 = { enablePush: false, ...(lookup && { lookup }) };
+        const h1 = { ...profileOpts.h1, ...lookup };
+        const h2 = { ...profileOpts.h2, ...lookup };
         fetchFuncs[key] = proto === 'h1'
             ? h1NoCache({ ...profileOpts, h1 }).fetch
             : noCache({ ...profileOpts, h1, h2 }).fetch;
@@ -98,7 +111,7 @@ export function skipLoggingFetchError(error) {
         || error?.code === 'ETIMEDOUT';
 }
 
-function selectFetchFunc(options, profile = 'default') {
+function selectFetchFunc(options, profile = PROFILE_DEFAULT) {
     let order = 'default';
     if (options.ipv6first) {
         order = 'ipv6first';
@@ -209,15 +222,15 @@ function doFetch(profile, options) {
 }
 
 export function fetchStreamKeepAlive(options) {
-    return doFetch('keepAlive', options);
+    return doFetch(PROFILE_KEEP_ALIVE, options);
 }
 
 export function fetchStream(options) {
-    return doFetch('default', options);
+    return doFetch(PROFILE_DEFAULT, options);
 };
 
 export function fetchStreamAuthorized(options) {
-    return doFetch('authorized', options);
+    return doFetch(PROFILE_AUTHORIZED, options);
 };
 
 export function fetchData(options) {

From 972d51ca8e4f39f730a9d68b7947813eab241aeb Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 20:07:52 +0300
Subject: [PATCH 12/18] add ip order consts

---
 lib/fetch.js | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index cce71b7a0..1ae2b8639 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -18,10 +18,14 @@ const makeLookup = (order) => (hostname, options, callback) =>
     });
 
 // `ipv6first` order requires Node >= 20.13. autoSelectFamily falls back to the other family on connect failure.
+const ORDER_DEFAULT = 'default';
+const ORDER_IPV6_FIRST = 'ipv6first';
+const ORDER_IPV4_FIRST = 'ipv4first';
+
 const LOOKUPS = {
-    default: undefined,     // Node's global resolver order.
-    ipv6first: { lookup: makeLookup('ipv6first') },
-    ipv4first: { lookup: makeLookup('ipv4first') }
+    [ORDER_DEFAULT]: undefined,     // Node's global resolver order.
+    [ORDER_IPV6_FIRST]: { lookup: makeLookup(ORDER_IPV6_FIRST) },
+    [ORDER_IPV4_FIRST]: { lookup: makeLookup(ORDER_IPV4_FIRST) }
 };
 
 const PROFILE_DEFAULT = 'default';
@@ -112,12 +116,12 @@ export function skipLoggingFetchError(error) {
 }
 
 function selectFetchFunc(options, profile = PROFILE_DEFAULT) {
-    let order = 'default';
+    let order = ORDER_DEFAULT;
     if (options.ipv6first) {
-        order = 'ipv6first';
+        order = ORDER_IPV6_FIRST;
     }
     if (options.ipv4first) {
-        order = 'ipv4first';
+        order = ORDER_IPV4_FIRST;
     }
     return getFetchFunc(profile, options.disable_http2 ? 'h1' : 'h2', order);
 }

From 034417864a0f7baba616db003e48d68c58e407a0 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 20:21:46 +0300
Subject: [PATCH 13/18] simplify `fetch` call

---
 lib/fetch.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 1ae2b8639..e6c948d3e 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -97,9 +97,7 @@ function getFetchFunc(profile, proto, order) {
         const lookup = LOOKUPS[order];
         const h1 = { ...profileOpts.h1, ...lookup };
         const h2 = { ...profileOpts.h2, ...lookup };
-        fetchFuncs[key] = proto === 'h1'
-            ? h1NoCache({ ...profileOpts, h1 }).fetch
-            : noCache({ ...profileOpts, h1, h2 }).fetch;
+        fetchFuncs[key] = (proto === 'h1' ? h1NoCache : noCache)({ ...profileOpts, h1, h2 }).fetch;
     }
     return fetchFuncs[key];
 }

From 0630262ac90a09371d16fb257d255a44af180c50 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 20:37:26 +0300
Subject: [PATCH 14/18] support `options.ipv4first`

---
 lib/fetch.js | 3 +--
 lib/utils.js | 4 ++++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index e6c948d3e..1b80ea8c5 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -117,8 +117,7 @@ function selectFetchFunc(options, profile = PROFILE_DEFAULT) {
     let order = ORDER_DEFAULT;
     if (options.ipv6first) {
         order = ORDER_IPV6_FIRST;
-    }
-    if (options.ipv4first) {
+    } else if (options.ipv4first) {
         order = ORDER_IPV4_FIRST;
     }
     return getFetchFunc(profile, options.disable_http2 ? 'h1' : 'h2', order);
diff --git a/lib/utils.js b/lib/utils.js
index 0ca748d7a..de2547b5b 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -155,6 +155,8 @@ export function prepareRequestOptions(request_options, options) {
                     }
                     if (proxy.ipv6first) {
                         request_options.ipv6first = true;
+                    } else if (proxy.ipv4first) {
+                        request_options.ipv4first = true;
                     }
                     if (proxy.disable_language) {
                         disable_language = true;
@@ -173,6 +175,8 @@ export function prepareRequestOptions(request_options, options) {
 
             if (options?.ipv6first) {
                 request_options.ipv6first = true;
+            } else if (options?.ipv4first) {
+                request_options.ipv4first = true;
             }
 
             if (options?.user_agent) {

From f0197dffe1d39adbebf8d90d7f4daa2517f94949 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 20:45:27 +0300
Subject: [PATCH 15/18] add `FETCH_BY_PROTOCOL`

---
 lib/fetch.js | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index 1b80ea8c5..e2e66599b 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -47,6 +47,14 @@ const PROFILES = {
     }
 };
 
+const H1 = 'h1';
+const H2 = 'h2';
+
+const FETCH_BY_PROTOCOL = {
+    [H1]: h1NoCache,
+    [H2]: noCache
+};
+
 // Lazily created fetch contexts, memoized per profile/protocol/dns order combination.
 const fetchFuncs = {};
 /*
@@ -90,14 +98,16 @@ const fetchH1 = h1NoCache({
 }).fetch;
 */
 
-function getFetchFunc(profile, proto, order) {
-    const key = `${profile}:${proto}:${order}`;
+function getFetchFunc(profile, protocol, order) {
+    const key = `${profile}:${protocol}:${order}`;
     if (!fetchFuncs[key]) {
         const profileOpts = PROFILES[profile];
         const lookup = LOOKUPS[order];
         const h1 = { ...profileOpts.h1, ...lookup };
         const h2 = { ...profileOpts.h2, ...lookup };
-        fetchFuncs[key] = (proto === 'h1' ? h1NoCache : noCache)({ ...profileOpts, h1, h2 }).fetch;
+        const fetchOptions = { ...profileOpts, h1, h2 };
+        const fetchFunc = FETCH_BY_PROTOCOL[protocol];
+        fetchFuncs[key] = fetchFunc(fetchOptions).fetch;
     }
     return fetchFuncs[key];
 }
@@ -120,7 +130,7 @@ function selectFetchFunc(options, profile = PROFILE_DEFAULT) {
     } else if (options.ipv4first) {
         order = ORDER_IPV4_FIRST;
     }
-    return getFetchFunc(profile, options.disable_http2 ? 'h1' : 'h2', order);
+    return getFetchFunc(profile, options.disable_http2 ? H1 : H2, order);
 }
 
 function doFetch(profile, options) {

From 945bf2c4e51ad5ed55510c2ac33a64c3a83500d0 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Wed, 7 Oct 2026 22:37:38 +0300
Subject: [PATCH 16/18] read `providerOptions.app.ipv6first`

---
 lib/utils.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/utils.js b/lib/utils.js
index de2547b5b..3e5735d72 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -126,6 +126,15 @@ export function prepareRequestOptions(request_options, options) {
                     request_options.headers[key] = value;
                 }
             }
+
+            // Lowest priority for `ipv6first/ipv4first` from `providerOptions`.
+            if (options?.getProviderOptions) {
+                if (options.getProviderOptions('app.ipv6first')) {
+                    request_options.ipv6first = true;
+                } else if (options.getProviderOptions('app.ipv4first')) {
+                    request_options.ipv4first = true;
+                }
+            }
             
             if (CONFIG.PROXY || options?.proxy) {
 
@@ -153,6 +162,7 @@ export function prepareRequestOptions(request_options, options) {
                     if (proxy.disable_http2) {
                         request_options.disable_http2 = true;
                     }
+                    // Middle priority for `ipv6first/ipv4first` from `proxy`.
                     if (proxy.ipv6first) {
                         request_options.ipv6first = true;
                     } else if (proxy.ipv4first) {
@@ -173,6 +183,7 @@ export function prepareRequestOptions(request_options, options) {
                 }
             }
 
+            // Highest priority for `ipv6first/ipv4first` from `options`.
             if (options?.ipv6first) {
                 request_options.ipv6first = true;
             } else if (options?.ipv4first) {

From fbbda76e8267eadd208807b23b6960fb8ad22cfa Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Thu, 8 Oct 2026 16:06:23 +0300
Subject: [PATCH 17/18] fetch: debug connection

---
 lib/fetch.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/fetch.js b/lib/fetch.js
index e2e66599b..d65a2e1ec 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -1,9 +1,20 @@
 import { URL } from 'url';
 import dns from 'node:dns';
+import diagnostics_channel from 'node:diagnostics_channel';
 import { h1NoCache, noCache, createUrl, AbortController, AbortError, FetchError } from '@adobe/fetch';
 import { serialize as serializeCookie, parse as parseCookie } from 'cookie';
 import log from '../logging.js';
 
+// Log the actual IP each outgoing connection is made to (with autoSelectFamily it may differ from lookup order).
+diagnostics_channel.subscribe('net.client.socket', ({ socket }) => {
+    socket.once('connect', () => {
+        // Skip non-http connections (redis, etc.).
+        if (socket.remotePort !== 443 && socket.remotePort !== 80) return;
+        const host = socket.servername || socket._host || '';
+        log(`   -- connected`, host, `${socket.remoteAddress} (${socket.remoteFamily}):${socket.remotePort}`);
+    });
+});
+
 const makeLookup = (order) => (hostname, options, callback) =>
     dns.lookup(hostname, { ...options, order }, (error, address, family) => {
         if (error) {

From 7282f1021274c00580484ef85aa3f9e4a3d0dd35 Mon Sep 17 00:00:00 2001
From: Nazar Leush <n.leush@gmail.com>
Date: Thu, 8 Oct 2026 16:22:36 +0300
Subject: [PATCH 18/18] comment debug blocks

---
 lib/fetch.js | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/fetch.js b/lib/fetch.js
index d65a2e1ec..c19d85349 100644
--- a/lib/fetch.js
+++ b/lib/fetch.js
@@ -1,11 +1,13 @@
 import { URL } from 'url';
 import dns from 'node:dns';
-import diagnostics_channel from 'node:diagnostics_channel';
 import { h1NoCache, noCache, createUrl, AbortController, AbortError, FetchError } from '@adobe/fetch';
 import { serialize as serializeCookie, parse as parseCookie } from 'cookie';
 import log from '../logging.js';
 
-// Log the actual IP each outgoing connection is made to (with autoSelectFamily it may differ from lookup order).
+/*
+import diagnostics_channel from 'node:diagnostics_channel';
+
+// Log the actual IP each outgoing connection is made to.
 diagnostics_channel.subscribe('net.client.socket', ({ socket }) => {
     socket.once('connect', () => {
         // Skip non-http connections (redis, etc.).
@@ -14,7 +16,13 @@ diagnostics_channel.subscribe('net.client.socket', ({ socket }) => {
         log(`   -- connected`, host, `${socket.remoteAddress} (${socket.remoteFamily}):${socket.remotePort}`);
     });
 });
+*/
 
+const makeLookup = (order) => (hostname, options, callback) =>
+    dns.lookup(hostname, { ...options, order }, callback);
+
+// Debug lookup.
+/*
 const makeLookup = (order) => (hostname, options, callback) =>
     dns.lookup(hostname, { ...options, order }, (error, address, family) => {
         if (error) {
@@ -27,6 +35,7 @@ const makeLookup = (order) => (hostname, options, callback) =>
         }
         callback(error, address, family);
     });
+*/
 
 // `ipv6first` order requires Node >= 20.13. autoSelectFamily falls back to the other family on connect failure.
 const ORDER_DEFAULT = 'default';