From 86369e4ac58ffaf272f38b0f372d8092ba15613f Mon Sep 17 00:00:00 2001
From: cjihrig <cjihrig@gmail.com>
Date: Fri, 25 Oct 2019 21:17:06 -0400
Subject: [PATCH] http: support readable hwm in IncomingMessage

This commit causes http.IncomingMessage instances to set their
readableHighWaterMark value the same value used in the underlying
socket.

PR-URL: https://github.com/nodejs/node/pull/30135
Fixes: https://github.com/nodejs/node/issues/30107
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
---
 doc/api/http.md                               |  4 ++++
 lib/_http_incoming.js                         | 10 +++++++-
 .../test-http-incoming-message-options.js     | 24 +++++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-http-incoming-message-options.js

diff --git a/doc/api/http.md b/doc/api/http.md
index 2f6b27e10c652e..33778d5445ae4b 100644
--- a/doc/api/http.md
+++ b/doc/api/http.md
@@ -1659,6 +1659,10 @@ the request body should be sent.
 ## Class: `http.IncomingMessage`
 <!-- YAML
 added: v0.1.17
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/30135
+    description: The `readableHighWaterMark` value mirrors that of the socket.
 -->
 
 * Extends: {stream.Readable}
diff --git a/lib/_http_incoming.js b/lib/_http_incoming.js
index 56ff31af8b17c1..8f4c05c5fe5919 100644
--- a/lib/_http_incoming.js
+++ b/lib/_http_incoming.js
@@ -37,7 +37,15 @@ function readStop(socket) {
 
 /* Abstract base class for ServerRequest and ClientResponse. */
 function IncomingMessage(socket) {
-  Stream.Readable.call(this);
+  let streamOptions;
+
+  if (socket) {
+    streamOptions = {
+      highWaterMark: socket.readableHighWaterMark
+    };
+  }
+
+  Stream.Readable.call(this, streamOptions);
 
   this._readableState.readingMore = true;
 
diff --git a/test/parallel/test-http-incoming-message-options.js b/test/parallel/test-http-incoming-message-options.js
new file mode 100644
index 00000000000000..61e178eb47aeda
--- /dev/null
+++ b/test/parallel/test-http-incoming-message-options.js
@@ -0,0 +1,24 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+const net = require('net');
+const readableHighWaterMark = 1024;
+const server = http.createServer((req, res) => { res.end(); });
+
+server.listen(0, common.mustCall(() => {
+  const req = http.request({
+    port: server.address().port,
+    createConnection(options) {
+      options.readableHighWaterMark = readableHighWaterMark;
+      return net.createConnection(options);
+    }
+  }, common.mustCall((res) => {
+    assert.strictEqual(res.socket, req.socket);
+    assert.strictEqual(res.socket.readableHighWaterMark, readableHighWaterMark);
+    assert.strictEqual(res.readableHighWaterMark, readableHighWaterMark);
+    server.close();
+  }));
+
+  req.end();
+}));