http: add setDefaultHeaders option to http.request

doc/api/http.md

@@ -3848,8 +3848,13 @@ changes:
   * `port` {number} Port of remote server. **Default:** `defaultPort` if set,
     else `80`.
   * `protocol` {string} Protocol to use. **Default:** `'http:'`.
+  * `setDefaultHeaders` {boolean}: Specifies whether or not to automatically add
+    default headers such as `Connection`, `Content-Length`, `Transfer-Encoding`,
+    and `Host`. If set to `false` then all necessary headers must be added
+    manually. Defaults to `true`.
   * `setHost` {boolean}: Specifies whether or not to automatically add the
-    `Host` header. Defaults to `true`.
+    `Host` header. If provided, this overrides `setDefaultHeaders`. Defaults to
+    `true`.
   * `signal` {AbortSignal}: An AbortSignal that may be used to abort an ongoing
     request.
   * `socketPath` {string} Unix domain socket. Cannot be used if one of `host`

lib/_http_client.js

@@ -199,7 +199,13 @@ function ClientRequest(input, options, cb) {
   const host = optsWithoutSignal.host = validateHost(options.hostname, 'hostname') ||
                                         validateHost(options.host, 'host') || 'localhost';
 
-  const setHost = (options.setHost === undefined || Boolean(options.setHost));
+  const setHost = options.setHost !== undefined ?
+    Boolean(options.setHost) :
+    options.setDefaultHeaders !== false;
+
+  this._removedConnection = options.setDefaultHeaders === false;
+  this._removedContLen = options.setDefaultHeaders === false;
+  this._removedTE = options.setDefaultHeaders === false;
 
   this.socketPath = options.socketPath;
 

test/parallel/test-http-dont-set-default-headers-with-set-header.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(common.mustCall(function(req, res) {
+  assert.deepStrictEqual(req.rawHeaders, [
+    'test', 'value',
+    'HOST', `127.0.0.1:${server.address().port}`,
+    'foo', 'bar',
+    'foo', 'baz',
+    'connection', 'close',
+  ]);
+
+  res.end('ok');
+  server.close();
+}));
+server.listen(0, common.localhostIPv4, function() {
+  const req = http.request({
+    method: 'POST',
+    host: common.localhostIPv4,
+    port: this.address().port,
+    setDefaultHeaders: false,
+  });
+
+  req.setHeader('test', 'value');
+  req.setHeader('HOST', `${common.localhostIPv4}:${server.address().port}`);
+  req.setHeader('foo', ['bar', 'baz']);
+  req.setHeader('connection', 'close');
+
+  req.end();
+});

test/parallel/test-http-dont-set-default-headers-with-setHost.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(common.mustCall(function(req, res) {
+  assert.deepStrictEqual(req.rawHeaders, [
+    'Host', `${common.localhostIPv4}:${server.address().port}`,
+  ]);
+
+  res.end('ok');
+  server.close();
+}));
+server.listen(0, common.localhostIPv4, function() {
+  http.request({
+    method: 'POST',
+    host: common.localhostIPv4,
+    port: this.address().port,
+    setDefaultHeaders: false,
+    setHost: true
+  }).end();
+});

test/parallel/test-http-dont-set-default-headers.js

@@ -0,0 +1,31 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(common.mustCall(function(req, res) {
+  assert.deepStrictEqual(req.rawHeaders, [
+    'host', `${common.localhostIPv4}:${server.address().port}`,
+    'foo', 'bar',
+    'test', 'value',
+    'foo', 'baz',
+  ]);
+
+  res.end('ok');
+  server.close();
+}));
+server.listen(0, common.localhostIPv4, function() {
+  http.request({
+    method: 'POST',
+    host: common.localhostIPv4,
+    port: this.address().port,
+    setDefaultHeaders: false,
+    headers: [
+      'host', `${common.localhostIPv4}:${server.address().port}`,
+      'foo', 'bar',
+      'test', 'value',
+      'foo', 'baz',
+    ]
+  }).end();
+});