From 9719ec1809f330c0436c96632518f1b19626b3e3 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Thu, 30 Jul 2020 16:58:08 +0200
Subject: [PATCH 1/3] http: provide keep-alive timeout response header

In http 1.1 persistent connection protocol there is a timing race where the
client sends the request and then the server kills the connection
(due to inactivity) before receiving the client's request.

By providing a keep-alive header it is possible to provide the client a
hint of when idle timeout would occur and avoid the race.

Fixes: https://github.com/nodejs/node/issues/34560
---
 lib/_http_outgoing.js                         |  7 +++++
 lib/_http_server.js                           |  1 +
 test/parallel/test-http-keep-alive-timeout.js | 28 +++++++++++++++++++
 3 files changed, 36 insertions(+)
 create mode 100644 test/parallel/test-http-keep-alive-timeout.js

diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index 868c74d3518cc0..d40105034c82e7 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -28,6 +28,7 @@ const {
   ObjectKeys,
   ObjectPrototypeHasOwnProperty,
   ObjectSetPrototypeOf,
+  MathFloor,
   Symbol,
 } = primordials;
 
@@ -123,6 +124,8 @@ function OutgoingMessage() {
   this._header = null;
   this[kOutHeaders] = null;
 
+  this._keepAliveTimeout = 0;
+
   this._onPendingData = noopPendingOutput;
 }
 ObjectSetPrototypeOf(OutgoingMessage.prototype, Stream.prototype);
@@ -424,6 +427,10 @@ function _storeHeader(firstLine, headers) {
         (state.contLen || this.useChunkedEncodingByDefault || this.agent);
     if (shouldSendKeepAlive) {
       header += 'Connection: keep-alive\r\n';
+      if (this._keepAliveTimeout) {
+        const timeoutSeconds = MathFloor(this._keepAliveTimeout - 500) / 1000;
+        header += `Keep-Alive: timeout=${timeoutSeconds}\r\n`;
+      }
     } else {
       this._last = true;
       header += 'Connection: close\r\n';
diff --git a/lib/_http_server.js b/lib/_http_server.js
index 084b67b6b3a6fe..0da43c3e3a8159 100644
--- a/lib/_http_server.js
+++ b/lib/_http_server.js
@@ -766,6 +766,7 @@ function parserOnIncoming(server, socket, state, req, keepAlive) {
   }
 
   const res = new server[kServerResponse](req);
+  res._keepAliveTimeout = server.keepAliveTimeout;
   res._onPendingData = updateOutgoingData.bind(undefined, socket, state);
 
   res.shouldKeepAlive = keepAlive;
diff --git a/test/parallel/test-http-keep-alive-timeout.js b/test/parallel/test-http-keep-alive-timeout.js
new file mode 100644
index 00000000000000..03e497231b323d
--- /dev/null
+++ b/test/parallel/test-http-keep-alive-timeout.js
@@ -0,0 +1,28 @@
+'use strict';
+
+const common = require('../common');
+const http = require('http');
+const assert = require('assert');
+
+const server = http.createServer(common.mustCall((req, res) => {
+  const body = 'hello world\n';
+
+  res.writeHead(200, { 'Content-Length': body.length });
+  res.write(body);
+  res.end();
+}));
+server.keepAliveTimeout = 12000;
+
+const agent = new http.Agent({ maxSockets: 1, keepAlive: true });
+
+server.listen(0, common.mustCall(function() {
+  http.get({
+    path: '/', port: this.address().port, agent: agent
+  }, common.mustCall((response) => {
+    response.resume();
+    assert.strictEqual(
+      response.headers['keep-alive'], 'timeout=11.5');
+    server.close();
+    agent.destroy();
+  }));
+}));

From 003e581088b6da260b11b37c8a9b2f80ac7cd90e Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Thu, 30 Jul 2020 17:05:41 +0200
Subject: [PATCH 2/3] fixup

---
 lib/_http_outgoing.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index d40105034c82e7..f444be8687db34 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -428,7 +428,7 @@ function _storeHeader(firstLine, headers) {
     if (shouldSendKeepAlive) {
       header += 'Connection: keep-alive\r\n';
       if (this._keepAliveTimeout) {
-        const timeoutSeconds = MathFloor(this._keepAliveTimeout - 500) / 1000;
+        const timeoutSeconds = MathFloor(this._keepAliveTimeout) / 1000;
         header += `Keep-Alive: timeout=${timeoutSeconds}\r\n`;
       }
     } else {

From b4e8b79fcf0e5f393cf11655f7172fb1d5274a63 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Thu, 30 Jul 2020 18:08:07 +0200
Subject: [PATCH 3/3] fixup

---
 test/parallel/test-http-keep-alive-timeout.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/parallel/test-http-keep-alive-timeout.js b/test/parallel/test-http-keep-alive-timeout.js
index 03e497231b323d..fccb267b8e9ee2 100644
--- a/test/parallel/test-http-keep-alive-timeout.js
+++ b/test/parallel/test-http-keep-alive-timeout.js
@@ -21,7 +21,7 @@ server.listen(0, common.mustCall(function() {
   }, common.mustCall((response) => {
     response.resume();
     assert.strictEqual(
-      response.headers['keep-alive'], 'timeout=11.5');
+      response.headers['keep-alive'], 'timeout=12');
     server.close();
     agent.destroy();
   }));