http2: add new connectionWindowSize option - #65619

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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.

This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.

That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.

Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.

This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.

En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.

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http2: add new connectionWindowSize option
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.

Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)

... and 42 files with indirect coverage changes

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
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(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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http2: add new connectionWindowSize option - #65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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@pimterry
http2: add new connectionWindowSize option
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Signed-off-by: Tim Perry <pimterry@gmail.com>
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
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})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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http2: add new connectionWindowSize option - #65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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@pimterry
http2: add new connectionWindowSize option
137d777
Signed-off-by: Tim Perry <pimterry@gmail.com>
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
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})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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http2: add new connectionWindowSize option - #65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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@pimterry
http2: add new connectionWindowSize option
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Signed-off-by: Tim Perry <pimterry@gmail.com>
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
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} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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http2: add new connectionWindowSize option - #65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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@pimterry
http2: add new connectionWindowSize option
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Signed-off-by: Tim Perry <pimterry@gmail.com>
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
http2: add new connectionWindowSize option - #65619
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pimterry:http2-connection-window-size-option
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http2: add new connectionWindowSize option#65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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http2: add new connectionWindowSize option
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
http2: add new connectionWindowSize option - #65619
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pimterry:http2-connection-window-size-option
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http2: add new connectionWindowSize option#65619
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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@pimterry
http2: add new connectionWindowSize option
137d777
Signed-off-by: Tim Perry <pimterry@gmail.com>
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
http2: add new connectionWindowSize option - #65619
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pimterry:http2-connection-window-size-option
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http2: add new connectionWindowSize option#65619
pimterry wants to merge 1 commit into
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#64623 massively increased the default HTTP/2 connection window size from 64KB bytes to 32MB.
This is definitely a good thing for bandwidth in common scenarios, but there's no way for users to opt-out of this change or to shrink the window themselves for other use cases.
That limitation is because the only way to change this today is through setLocalWindowSize, which is only available for dynamic changes after connection setup. Unfortunately, once an HTTP/2 connection is set up it's impossible to shrink the initial window back below the advertised amount (impossible in the protocol, not just our implementation), so changes only apply once the initial window has been used up. With a default of 32MB per session, that can take a while.
Shrinking the window can be useful as a quick workaround to preserve old behaviour, or to optimize for low-latency connections or constrained memory environments, where you want smaller buffers & more responsive backpressure instead of a huge window optimized for throughput over high-latency.
This PR adds a new HTTP/2 connectionWindowSize option to let you configure the initial connection window. If set, it overrides the initial window that's configured on nghttp2 before the session connects.
En route this also commonizes some option validation into validateSessionOptions, deduplicating some existing validation and giving a single place to add the validation for this new option.
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Aug 28, 2026
@pimterry
http2: add new connectionWindowSize option
137d777
Signed-off-by: Tim Perry <pimterry@gmail.com>
@pimterry
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http2-connection-window-size-option
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.06%. Comparing base (d6e67a5) to head (137d777).
⚠️ Report is 15 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #65619 +/- ##
==========================================
- Coverage 90.07% 90.06% -0.01% 
==========================================
Files 751 751 Lines 254881 254932 +51 Branches 48111 48124 +13 ==========================================
+ Hits 229582 229603 +21 - Misses 16486 16496 +10 - Partials 8813 8833 +20 
Files with missing linesCoverage Δ
lib/internal/http2/core.js95.10% <100.00%> (+0.02%)⬆️
lib/internal/http2/util.js92.93% <100.00%> (+0.04%)⬆️
src/node_http2.cc81.87% <100.00%> (+0.03%)⬆️
src/node_http2.h92.39% <100.00%> (+0.16%)⬆️
src/node_http2_state.h100.00% <ø> (ø)
... and 42 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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