cli: add --use-env-proxy

This does the same as NODE_USE_ENV_PROXY. When both are set,
like other options that can be configured from both sides,
the CLI flag takes precedence.

PR-URL: https://github.com/nodejs/node/pull/59151
Fixes: https://github.com/nodejs/node/issues/59100
Reviewed-By: Ilyas Shabi <ilyasshabi94@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

test/client-proxy/test-http-proxy-request.mjs

@@ -78,8 +78,6 @@ if (!common.isWindows) {
     REQUEST_URL: requestUrl,
     http_proxy: `http://localhost:${proxy.address().port}`,
     HTTP_PROXY: `http://localhost:${proxy2.address().port}`,
-  }, {
-    stdout: 'Hello world',
   });
   assert.deepStrictEqual(logs, expectedLogs);
   assert.strictEqual(stderr.trim(), '');

test/client-proxy/test-https-proxy-request.mjs

@@ -92,8 +92,6 @@ if (!common.isWindows) {
     https_proxy: `http://localhost:${proxy.address().port}`,
     HTTPS_PROXY: `http://localhost:${proxy2.address().port}`,
     NODE_EXTRA_CA_CERTS: fixtures.path('keys', 'fake-startcom-root-cert.pem'),
-  }, {
-    stdout: 'Hello world',
   });
   assert.deepStrictEqual(logs, expectedLogs);
   assert.strictEqual(stderr.trim(), '');

test/client-proxy/test-use-env-proxy-cli-http.mjs

@@ -0,0 +1,75 @@
+// This tests that --use-env-proxy works the same as NODE_USE_ENV_PROXY=1
+// for HTTP requests using the built-in http module and fetch API.
+
+import * as common from '../common/index.mjs';
+import assert from 'node:assert';
+import http from 'node:http';
+import { once } from 'events';
+import { createProxyServer, runProxiedRequest, checkProxiedFetch } from '../common/proxy-server.js';
+
+// Start a minimal proxy server.
+const { proxy, logs } = createProxyServer();
+proxy.listen(0);
+await once(proxy, 'listening');
+
+delete process.env.NODE_USE_ENV_PROXY; // Ensure the environment variable is not set.
+
+// Start a HTTP server to process the final request.
+const server = http.createServer(common.mustCall((req, res) => {
+  res.end('Hello world');
+}, 2));
+server.on('error', common.mustNotCall((err) => { console.error('Server error', err); }));
+server.listen(0);
+await once(server, 'listening');
+
+const serverHost = `localhost:${server.address().port}`;
+const requestUrl = `http://${serverHost}/test`;
+
+// Tests --use-env-proxy works with http builtins.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    REQUEST_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, ['--use-env-proxy']);
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+  assert.deepStrictEqual(logs, [{
+    method: 'GET',
+    url: requestUrl,
+    headers: {
+      'connection': 'keep-alive',
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  }]);
+}
+
+// Tests --use-env-proxy works with fetch and http.
+{
+  logs.splice(0, logs.length);
+  await checkProxiedFetch({
+    FETCH_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, {
+    stdout: 'Hello world',
+  }, ['--use-env-proxy']);
+
+  // FIXME(undici:4083): undici currently always tunnels the request over
+  // CONNECT if proxyTunnel is not explicitly set to false, but what we
+  // need is for it to be automatically false for HTTP requests to be
+  // consistent with curl.
+  assert.deepStrictEqual(logs, [{
+    method: 'CONNECT',
+    url: serverHost,
+    headers: {
+      'connection': 'close',
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  }]);
+}
+
+server.close();
+proxy.close();

test/client-proxy/test-use-env-proxy-cli-https.mjs

@@ -0,0 +1,81 @@
+// This tests that --use-env-proxy works the same as NODE_USE_ENV_PROXY=1
+// for HTTPS requests using the built-in https module and fetch API.
+
+import * as common from '../common/index.mjs';
+import fixtures from '../common/fixtures.js';
+import assert from 'node:assert';
+import { once } from 'events';
+import { createProxyServer, runProxiedRequest, checkProxiedFetch } from '../common/proxy-server.js';
+
+if (!common.hasCrypto) {
+  common.skip('missing crypto');
+}
+
+// https must be dynamically imported so that builds without crypto support
+// can skip it.
+const { default: https } = await import('node:https');
+
+// Start a minimal proxy server.
+const { proxy, logs } = createProxyServer();
+proxy.listen(0);
+await once(proxy, 'listening');
+
+delete process.env.NODE_USE_ENV_PROXY; // Ensure the environment variable is not set.
+// Start a HTTPS server to process the final request.
+const server = https.createServer({
+  cert: fixtures.readKey('agent8-cert.pem'),
+  key: fixtures.readKey('agent8-key.pem'),
+}, common.mustCall((req, res) => {
+  res.end('Hello world');
+}, 2));
+server.on('error', common.mustNotCall((err) => { console.error('Server error', err); }));
+server.listen(0);
+await once(server, 'listening');
+
+const serverHost = `localhost:${server.address().port}`;
+const requestUrl = `https://${serverHost}/test`;
+
+// Tests --use-env-proxy works with https builtins.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    REQUEST_URL: requestUrl,
+    HTTPS_PROXY: `http://localhost:${proxy.address().port}`,
+    NODE_EXTRA_CA_CERTS: fixtures.path('keys', 'fake-startcom-root-cert.pem'),
+  }, ['--use-env-proxy']);
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+  assert.deepStrictEqual(logs, [{
+    method: 'CONNECT',
+    url: serverHost,
+    headers: {
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  }]);
+}
+
+// Tests --use-env-proxy works with fetch and https.
+{
+  logs.splice(0, logs.length);
+  await checkProxiedFetch({
+    FETCH_URL: `https://${serverHost}/test`,
+    HTTPS_PROXY: `http://localhost:${proxy.address().port}`,
+    NODE_EXTRA_CA_CERTS: fixtures.path('keys', 'fake-startcom-root-cert.pem'),
+  }, {
+    stdout: 'Hello world',
+  }, ['--use-env-proxy']);
+  assert.deepStrictEqual(logs, [{
+    method: 'CONNECT',
+    url: serverHost,
+    headers: {
+      'connection': 'close',
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  }]);
+}
+
+server.close();
+proxy.close();

test/client-proxy/test-use-env-proxy-precedence.mjs

@@ -0,0 +1,117 @@
+// This tests the precedence and interaction between --use-env-proxy CLI flag
+// and NODE_USE_ENV_PROXY environment variable when both are set.
+
+import * as common from '../common/index.mjs';
+import assert from 'node:assert';
+import http from 'node:http';
+import { once } from 'events';
+import { createProxyServer, runProxiedRequest } from '../common/proxy-server.js';
+
+// Start a proxy server for testing
+const { proxy, logs } = createProxyServer();
+proxy.listen(0);
+await once(proxy, 'listening');
+
+// Start a HTTP server to process the final request
+const server = http.createServer(common.mustCall((req, res) => {
+  res.end('Hello world');
+}, 4));
+server.on('error', common.mustNotCall((err) => { console.error('Server error', err); }));
+server.listen(0);
+await once(server, 'listening');
+
+const serverHost = `localhost:${server.address().port}`;
+const requestUrl = `http://${serverHost}/test`;
+
+delete process.env.NODE_USE_ENV_PROXY; // Ensure the environment variable is not set.
+// NODE_USE_ENV_PROXY=1 and --use-env-proxy can be used at the same time.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    NODE_USE_ENV_PROXY: '1',
+    REQUEST_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, ['--use-env-proxy']);
+
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+
+  // Should use the proxy
+  assert.strictEqual(logs.length, 1);
+  assert.deepStrictEqual(logs[0], {
+    method: 'GET',
+    url: requestUrl,
+    headers: {
+      'connection': 'keep-alive',
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  });
+
+  logs.splice(0, logs.length);
+}
+
+// NODE_USE_ENV_PROXY=0 and --no-use-env-proxy can be used at the same time.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    NODE_USE_ENV_PROXY: '0',
+    REQUEST_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, ['--no-use-env-proxy']);
+
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+
+  // Should NOT use the proxy
+  assert.strictEqual(logs.length, 0);
+}
+
+// --use-env-proxy CLI flag takes precedence over NODE_USE_ENV_PROXY=0.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    NODE_USE_ENV_PROXY: '0',
+    REQUEST_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, ['--use-env-proxy']);
+
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+
+  // Should use the proxy because CLI flag takes precedence
+  assert.strictEqual(logs.length, 1);
+  assert.deepStrictEqual(logs[0], {
+    method: 'GET',
+    url: requestUrl,
+    headers: {
+      'connection': 'keep-alive',
+      'proxy-connection': 'keep-alive',
+      'host': serverHost,
+    },
+  });
+
+  logs.splice(0, logs.length);
+}
+
+// --no-use-env-proxy CLI flag disables the proxy even if NODE_USE_ENV_PROXY=1.
+{
+  const { code, signal, stderr, stdout } = await runProxiedRequest({
+    NODE_USE_ENV_PROXY: '1',
+    REQUEST_URL: requestUrl,
+    HTTP_PROXY: `http://localhost:${proxy.address().port}`,
+  }, ['--no-use-env-proxy']);
+
+  // Should NOT use the proxy because CLI flag takes precedence.
+  assert.strictEqual(stderr.trim(), '');
+  assert.match(stdout, /Hello world/);
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+  assert.strictEqual(logs.length, 0);
+}
+
+proxy.close();
+server.close();

test/common/proxy-server.js

@@ -142,11 +142,11 @@ function spawnPromisified(...args) {
   });
 }
 
-exports.checkProxiedFetch = async function(envExtension, expectation) {
+exports.checkProxiedFetch = async function(envExtension, expectation, cliArgsExtension = []) {
   const fixtures = require('./fixtures');
   const { code, signal, stdout, stderr } = await spawnPromisified(
     process.execPath,
-    [fixtures.path('fetch-and-log.mjs')], {
+    [...cliArgsExtension, fixtures.path('fetch-and-log.mjs')], {
       env: {
         ...process.env,
         ...envExtension,
@@ -166,11 +166,11 @@ exports.checkProxiedFetch = async function(envExtension, expectation) {
   });
 };
 
-exports.runProxiedRequest = async function(envExtension) {
+exports.runProxiedRequest = async function(envExtension, cliArgsExtension = []) {
   const fixtures = require('./fixtures');
   return spawnPromisified(
     process.execPath,
-    [fixtures.path('request-and-log.js')], {
+    [...cliArgsExtension, fixtures.path('request-and-log.js')], {
       env: {
         ...process.env,
         ...envExtension,