From 8d0c638583742d1cb43e8c7b965ebaf6f51bf69a Mon Sep 17 00:00:00 2001
From: Roy Sommer <roy@sommer.co.il>
Date: Fri, 21 Dec 2018 20:17:15 +0200
Subject: [PATCH] lib: support overriding http\s.globalAgent

Overriding `require('http[s]').globalAgent` is now respected by
consequent requests.

In order to achieve that, the following changes were made:

1. Implmentation in `http`: `module.exports.globalAgent` is now defined
through `Object.defineProperty`. Its getter and setter return \ set
`require('_http_agent').globalAgent`.

2. Implementation in `https`: the https `globalAgent` is not the same
as `_http_agent`, and is defined in `https` module itself. Therefore,
the fix here was to simply use `module.exports.globalAgent` to support
mutation.

3. According tests were added for both `http` and `https`, where in
both we create a server, set the default agent to a newly created
instance and make a request to that server. We then assert that the
given instance was actually used by inspecting its sockets property.

Fixes: https://github.com/nodejs/node/issues/23281

PR-URL: https://github.com/nodejs/node/pull/25170
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/http.js                                   | 16 ++++++--
 lib/https.js                                  |  2 +-
 .../test-http-client-override-global-agent.js | 26 +++++++++++++
 ...test-https-client-override-global-agent.js | 38 +++++++++++++++++++
 4 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 test/parallel/test-http-client-override-global-agent.js
 create mode 100644 test/parallel/test-https-client-override-global-agent.js

diff --git a/lib/http.js b/lib/http.js
index e3707ffa62b25d..5f2fe6dc68f571 100644
--- a/lib/http.js
+++ b/lib/http.js
@@ -21,7 +21,7 @@
 
 'use strict';
 
-const { Agent, globalAgent } = require('_http_agent');
+const httpAgent = require('_http_agent');
 const { ClientRequest } = require('_http_client');
 const { methods } = require('_http_common');
 const { IncomingMessage } = require('_http_incoming');
@@ -52,9 +52,8 @@ module.exports = {
   _connectionListener,
   METHODS: methods.slice().sort(),
   STATUS_CODES,
-  Agent,
+  Agent: httpAgent.Agent,
   ClientRequest,
-  globalAgent,
   IncomingMessage,
   OutgoingMessage,
   Server,
@@ -76,3 +75,14 @@ Object.defineProperty(module.exports, 'maxHeaderSize', {
     return maxHeaderSize;
   }
 });
+
+Object.defineProperty(module.exports, 'globalAgent', {
+  configurable: true,
+  enumerable: true,
+  get() {
+    return httpAgent.globalAgent;
+  },
+  set(value) {
+    httpAgent.globalAgent = value;
+  }
+});
diff --git a/lib/https.js b/lib/https.js
index 0854c3d440577a..06b37c2143da9d 100644
--- a/lib/https.js
+++ b/lib/https.js
@@ -294,7 +294,7 @@ function request(...args) {
     options = util._extend(options, args.shift());
   }
 
-  options._defaultAgent = globalAgent;
+  options._defaultAgent = module.exports.globalAgent;
   args.unshift(options);
 
   return new ClientRequest(...args);
diff --git a/test/parallel/test-http-client-override-global-agent.js b/test/parallel/test-http-client-override-global-agent.js
new file mode 100644
index 00000000000000..c36c9d26a8dd63
--- /dev/null
+++ b/test/parallel/test-http-client-override-global-agent.js
@@ -0,0 +1,26 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+const server = http.Server(common.mustCall((req, res) => {
+  res.writeHead(200);
+  res.end('Hello, World!');
+}));
+
+server.listen(0, common.mustCall(() => {
+  const agent = new http.Agent();
+  const name = agent.getName({ port: server.address().port });
+  http.globalAgent = agent;
+
+  makeRequest();
+  assert(agent.sockets.hasOwnProperty(name)); // agent has indeed been used
+}));
+
+function makeRequest() {
+  const req = http.get({
+    port: server.address().port
+  });
+  req.on('close', () =>
+    server.close());
+}
diff --git a/test/parallel/test-https-client-override-global-agent.js b/test/parallel/test-https-client-override-global-agent.js
new file mode 100644
index 00000000000000..12b5ae596bc837
--- /dev/null
+++ b/test/parallel/test-https-client-override-global-agent.js
@@ -0,0 +1,38 @@
+'use strict';
+const common = require('../common');
+const fixtures = require('../common/fixtures');
+const assert = require('assert');
+const https = require('https');
+
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+
+// Disable strict server certificate validation by the client
+process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
+
+const options = {
+  key: fixtures.readKey('agent1-key.pem'),
+  cert: fixtures.readKey('agent1-cert.pem')
+};
+
+const server = https.Server(options, common.mustCall((req, res) => {
+  res.writeHead(200);
+  res.end('Hello, World!');
+}));
+
+server.listen(0, common.mustCall(() => {
+  const agent = new https.Agent();
+  const name = agent.getName({ port: server.address().port });
+  https.globalAgent = agent;
+
+  makeRequest();
+  assert(agent.sockets.hasOwnProperty(name)); // agent has indeed been used
+}));
+
+function makeRequest() {
+  const req = https.get({
+    port: server.address().port
+  });
+  req.on('close', () =>
+    server.close());
+}