first pass at common proxy determining logic

packages/node_modules/@node-red/nodes/core/network/10-mqtt.js

@@ -16,6 +16,7 @@
 
 module.exports = function(RED) {
     "use strict";
+    const { getProxyForUrl } = require('./lib/proxyHelper');
     var mqtt = require("mqtt");
     var isUtf8 = require('is-utf8');
     var HttpsProxyAgent = require('https-proxy-agent');
@@ -592,17 +593,8 @@ module.exports = function(RED) {
                     // Only for ws or wss, check if proxy env var for additional configuration
                     if (node.brokerurl.indexOf("wss://") > -1 || node.brokerurl.indexOf("ws://") > -1) {
                         // check if proxy is set in env
-                        let prox, noprox, noproxy;
+                        const prox = getProxyForUrl(node.brokerurl, RED.settings.proxyOptions);
-                        if (process.env.http_proxy) { prox = process.env.http_proxy; }
+                        if (prox) {
-                        if (process.env.HTTP_PROXY) { prox = process.env.HTTP_PROXY; }
-                        if (process.env.no_proxy) { noprox = process.env.no_proxy.split(","); }
-                        if (process.env.NO_PROXY) { noprox = process.env.NO_PROXY.split(","); }
-                        if (noprox) {
-                            for (var i = 0; i < noprox.length; i += 1) {
-                                if (node.brokerurl.indexOf(noprox[i].trim()) !== -1) { noproxy = true; }
-                            }
-                        }
-                        if (prox && !noproxy) {
                             var parsedUrl = url.parse(node.brokerurl);
                             var proxyOpts = url.parse(prox);
                             // true for wss

packages/node_modules/@node-red/nodes/core/network/21-httprequest.js

@@ -16,6 +16,7 @@
 
 module.exports = function(RED) {
     "use strict";
+    const { getProxyForUrl, parseUrl } = require('./lib/proxyHelper');
     const got = require("got");
     const {CookieJar} = require("tough-cookie");
     const { HttpProxyAgent, HttpsProxyAgent } = require('hpagent');
@@ -86,19 +87,18 @@ in your Node-RED user directory (${RED.settings.userDir}).
         if (n.paytoqs === true || n.paytoqs === "query") { paytoqs = true; }
         else if (n.paytoqs === "body") { paytobody = true; }
 
-
+        let proxyConfig = n.proxy ? RED.nodes.getNode(n.proxy) || {} : null
-        var prox, noprox;
+        const getProxy = (url) => {
-        if (process.env.http_proxy) { prox = process.env.http_proxy; }
+            const proxyOptions = Object.assign({}, RED.settings.proxyOptions);
-        if (process.env.HTTP_PROXY) { prox = process.env.HTTP_PROXY; }
+            if (n.proxy && proxyConfig) {
-        if (process.env.no_proxy) { noprox = process.env.no_proxy.split(","); }
+                proxyOptions.env = {
-        if (process.env.NO_PROXY) { noprox = process.env.NO_PROXY.split(","); }
+                    no_proxy: (proxyConfig.noproxy || []).join(','),
-
+                    http_proxy: (proxyConfig.url)
-        var proxyConfig = null;
-        if (n.proxy) {
-            proxyConfig = RED.nodes.getNode(n.proxy);
-            prox = proxyConfig.url;
-            noprox = proxyConfig.noproxy;
                 }
+            }
+            return getProxyForUrl(url, proxyOptions)
+        }
+        let prox = getProxy(nodeUrl || '')
 
         let timingLog = false;
         if (RED.settings.hasOwnProperty("httpRequestTimingLog")) {
@@ -171,7 +171,11 @@ in your Node-RED user directory (${RED.settings.userDir}).
                     url = "http://"+url;
                 }
             }
-
+            // before any parameters are appended to the `url`, lets check see if the proxy needs a refresh
+            let proxyUrl = prox; // The proxyUrl determined for `nodeUrl`
+            if(url !== nodeUrl) {
+                proxyUrl = getProxy(url)
+            }
             // The Request module used in Node-RED 1.x was tolerant of query strings that
             // were partially encoded. For example - "?a=hello%20there&b=20%"
             // The GOT module doesn't like that.
@@ -507,27 +511,25 @@ in your Node-RED user directory (${RED.settings.userDir}).
                 opts.headers[clSet] = opts.headers['content-length'];
                 delete opts.headers['content-length'];
             }
-
+            if (!opts.headers.hasOwnProperty('user-agent')) {
-            var noproxy;
+                opts.headers['user-agent'] = 'Mozilla/5.0 (Node-RED)';
-            if (noprox) {
-                for (var i = 0; i < noprox.length; i += 1) {
-                    if (url.indexOf(noprox[i]) !== -1) { noproxy=true; }
             }
-            }
+            if (proxyUrl) {
-            if (prox && !noproxy) {
+                var match = proxyUrl.match(/^(https?:\/\/)?(.+)?:([0-9]+)?/i);
-                var match = prox.match(/^(https?:\/\/)?(.+)?:([0-9]+)?/i);
                 if (match) {
-                    let proxyAgent;
+                    const proxyURL = parseUrl(proxyUrl)
-                    let proxyURL = new URL(prox);
                     //set username/password to null to stop empty creds header
+                    /** @type {HttpProxyAgentOptions} */
                     let proxyOptions = {
-                        proxy: {
+                        proxy: proxyUrl,
-                            protocol: proxyURL.protocol,
+                        // proxy: {
-                            hostname: proxyURL.hostname,
+                        //     protocol: proxyURL.protocol,
-                            port: proxyURL.port,
+                        //     hostname: proxyURL.hostname,
-                            username: null,
+                        //     port: proxyURL.port,
-                            password: null
+                        //     username: null,
-                        },
+                        //     password: null
+                        // },
+                        scheduling: 'lifo',
                         maxFreeSockets: 256,
                         maxSockets: 256,
                         keepAlive: true
@@ -536,21 +538,23 @@ in your Node-RED user directory (${RED.settings.userDir}).
                         let proxyUsername = proxyConfig.credentials.username || '';
                         let proxyPassword = proxyConfig.credentials.password || '';
                         if (proxyUsername || proxyPassword) {
+                            proxyOptions.proxy = proxyURL
                             proxyOptions.proxy.username = proxyUsername;
                             proxyOptions.proxy.password = proxyPassword;
                         }
                     } else if (proxyURL.username || proxyURL.password){
-                        proxyOptions.proxy.username = proxyURL.username;
+                        proxyOptions.proxy = proxyURL
-                        proxyOptions.proxy.password = proxyURL.password;
+                        // proxyOptions.proxy.username = proxyURL.username;
+                        // proxyOptions.proxy.password = proxyURL.password;
                     }
                     //need both incase of http -> https redirect
                     opts.agent = {
                         http: new HttpProxyAgent(proxyOptions),
-                        https: new HttpsProxyAgent(proxyOptions)
+                        https: new HttpProxyAgent(proxyOptions)
                     };
 
                 } else {
-                    node.warn("Bad proxy url: "+ prox);
+                    node.warn("Bad proxy url: "+ proxyUrl);
                 }
             }
             if (tlsNode) {

packages/node_modules/@node-red/nodes/core/network/22-websocket.js

@@ -68,21 +68,9 @@ module.exports = function(RED) {
 
         function startconn() {    // Connect to remote endpoint
             node.tout = null;
-            var prox, noprox;
+            const prox = getProxyForUrl(node.brokerurl, RED.settings.proxyOptions);
-            if (process.env.http_proxy) { prox = process.env.http_proxy; }
+            let agent = undefined;
-            if (process.env.HTTP_PROXY) { prox = process.env.HTTP_PROXY; }
+            if (prox) {
-            if (process.env.no_proxy) { noprox = process.env.no_proxy.split(","); }
-            if (process.env.NO_PROXY) { noprox = process.env.NO_PROXY.split(","); }
-
-            var noproxy = false;
-            if (noprox) {
-                for (var i in noprox) {
-                    if (node.path.indexOf(noprox[i].trim()) !== -1) { noproxy=true; }
-                }
-            }
-
-            var agent = undefined;
-            if (prox && !noproxy) {
                 agent = new HttpsProxyAgent(prox);
             }
 

packages/node_modules/@node-red/nodes/core/network/lib/proxyHelper.js

@@ -0,0 +1,215 @@
+/*
+The MIT License
+
+Copyright (C) 2016-2018 Rob Wu <rob@robwu.nl>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+*/
+
+/* 
+This proxy helper is heavily based on the proxy helper from Rob Wu as detailed above.
+It has been modified to work with the Node-RED runtime environment.
+The license for the original code is reproduced above.
+*/
+
+
+/**
+ * Parse a URL into its components.
+ * @param {String} url The URL to parse
+ * @returns {URL}
+ */
+const parseUrl = (url) => {
+    let parsedUrl = {
+        protocol: null,
+        host: null,
+        port: null,
+        hostname: null,
+        query: null,
+        href: null
+    }
+    try {
+        if (!url) { return parsedUrl }
+        parsedUrl = new URL(url)
+    } catch (error) {
+        // dont throw error
+    }
+    return parsedUrl
+}
+
+const DEFAULT_PORTS = {
+    ftp: 21,
+    gopher: 70,
+    http: 80,
+    https: 443,
+    ws: 80,
+    wss: 443,
+    mqtt: 1880,
+    mqtts: 8883
+}
+
+/**
+ * @typedef {Object} ProxyOptions
+ * @property {string} mode - Legacy mode is for non-strict previous proxy determination logic (node-red < v3.1) (default 'legacy')
+ * @property {boolean} favourUpperCase - Favour UPPER_CASE *_PROXY env vars (default false)
+ * @property {boolean} lowerCaseOnly - Prevent UPPER_CASE *_PROXY env vars being used. (default false)
+ * @property {boolean} excludeNpm - Prevent npm_config_*_proxy env vars being used. (default false)
+ * @property {object} env - The environment object to use (default process.env)
+ */
+
+/**
+ * Get the proxy URL for a given URL.
+ * @param {string|URL} url - The URL, or the result from url.parse.
+ * @param {ProxyOptions} [options] - The options object (optional)
+ * @return {string} The URL of the proxy that should handle the request to the
+ *  given URL. If no proxy is set, this will be an empty string.
+ */
+function getProxyForUrl(url, options) {
+    url = url || ''
+    const defaultOptions = {
+        mode: 'legacy', // TODO: change to 'strict' in V4.x
+        lowerCaseOnly: false,
+        favourUpperCase: false,
+        excludeNpm: false,
+    }
+    options = Object.assign({}, defaultOptions, options)
+
+    //TODO: V4.x default: if mode is not set, default to strict mode
+    // if (options.mode === 'legacy') {
+    if (options.mode !== 'strict') {
+        return legacyGetProxyForUrl(url, options.env || process.env)
+    }
+   
+    const parsedUrl = typeof url === 'string' ? parseUrl(url) : url || {}
+    let proto = parsedUrl.protocol
+    let hostname = parsedUrl.host
+    let port = parsedUrl.port
+    if (typeof hostname !== 'string' || !hostname || typeof proto !== 'string') {
+        return ''  // Don't proxy URLs without a valid scheme or host.
+    }
+
+    proto = proto.split(':', 1)[0]
+    // Stripping ports in this way instead of using parsedUrl.hostname to make
+    // sure that the brackets around IPv6 addresses are kept.
+    hostname = hostname.replace(/:\d*$/, '')
+    port = parseInt(port) || DEFAULT_PORTS[proto] || 0
+    if (!shouldProxy(hostname, port, options)) {
+        return ''  // Don't proxy URLs that match NO_PROXY.
+    }
+
+    let proxy =
+        getEnv('npm_config_' + proto + '_proxy', options) ||
+        getEnv(proto + '_proxy', options) ||
+        getEnv('npm_config_proxy', options) ||
+        getEnv('all_proxy', options)
+    if (proxy && proxy.indexOf('://') === -1) {
+        // Missing scheme in proxy, default to the requested URL's scheme.
+        proxy = proto + '://' + proxy
+    }
+    return proxy
+}
+
+/**
+ * Get the proxy URL for a given URL.
+ * For node-red < v3.1 or compatibility mode
+ * @param {string} url The URL to check for proxying
+ * @param {object} [env] The environment object to use (default process.env)
+ * @returns 
+ */
+function legacyGetProxyForUrl(url, env) {
+    env = env || process.env
+    let prox, noprox;
+    if (env.http_proxy) { prox = env.http_proxy; }
+    if (env.HTTP_PROXY) { prox = env.HTTP_PROXY; }
+    if (env.no_proxy) { noprox = env.no_proxy.split(","); }
+    if (env.NO_PROXY) { noprox = env.NO_PROXY.split(","); }
+
+    let noproxy = false;
+    if (noprox) {
+        for (let i in noprox) {
+            if (url.indexOf(noprox[i].trim()) !== -1) { noproxy=true; }
+        }
+    }
+    if (prox && !noproxy) {
+        return prox
+    }
+    return ""
+}
+
+/**
+ * Determines whether a given URL should be proxied.
+ *
+ * @param {string} hostname - The host name of the URL.
+ * @param {number} port - The effective port of the URL.
+ * @returns {boolean} Whether the given URL should be proxied.
+ * @private
+ */
+function shouldProxy(hostname, port, options) {
+    const NO_PROXY =
+        (getEnv('npm_config_no_proxy', options) || getEnv('no_proxy', options)).toLowerCase()
+    if (!NO_PROXY) {
+        return true  // Always proxy if NO_PROXY is not set.
+    }
+    if (NO_PROXY === '*') {
+        return false  // Never proxy if wildcard is set.
+    }
+
+    return NO_PROXY.split(/[,\s]/).every(function (proxy) {
+        if (!proxy) {
+            return true  // Skip zero-length hosts.
+        }
+        const parsedProxy = proxy.match(/^(.+):(\d+)$/)
+        let parsedProxyHostname = parsedProxy ? parsedProxy[1] : proxy
+        const parsedProxyPort = parsedProxy ? parseInt(parsedProxy[2]) : 0
+        if (parsedProxyPort && parsedProxyPort !== port) {
+            return true  // Skip if ports don't match.
+        }
+
+        if (!/^[.*]/.test(parsedProxyHostname)) {
+            // No wildcards, so stop proxying if there is an exact match.
+            return hostname !== parsedProxyHostname
+        }
+
+        if (parsedProxyHostname.charAt(0) === '*') {
+            // Remove leading wildcard.
+            parsedProxyHostname = parsedProxyHostname.slice(1)
+        }
+        // Stop proxying if the hostname ends with the no_proxy host.
+        return !hostname.endsWith(parsedProxyHostname)
+    })
+}
+
+/**
+ * Get the value for an environment constiable.
+ *
+ * @param {string} key - The name of the environment constiable.
+ * @param {ProxyOptions} options - The name of the environment constiable.
+ * @return {string} The value of the environment constiable.
+ * @private
+ */
+function getEnv(key, options) {
+    const env = (options && options.env) || process.env
+    if (options && options.excludeNpm === true) {
+        if (key.startsWith('npm_config_')) {
+            return ''
+        }
+    }
+    if (options && options.lowerCaseOnly === true) {
+        return env[key.toLowerCase()] || ''
+    } else if (options && options.favourUpperCase === true) {
+        return env[key.toUpperCase()] ||  env[key.toLowerCase()] || ''
+    }
+    return env[key.toLowerCase()] || env[key.toUpperCase()] || ''
+}
+
+module.exports = {
+    getProxyForUrl,
+    parseUrl
+}

test/nodes/core/network/lib/proxyHelper_spec.js

@@ -0,0 +1,648 @@
+const should = require("should");
+
+/*****
+
+Issues with the current *_proxy implementation in Node-RED:
+    * no_proxy should not be case-sensitive
+        * i.e. if no_proxy contains "example.com", then "example.com" and "EXAMPLE.COM" should both be excluded
+    * no_proxy with protocols that have a default port are not considered
+        * i.e. if no_proxy contains "example.com:443", then "https://example.com" should be excluded
+        * i.e. if no_proxy contains "example.com:80", then "http://example.com" should be excluded
+        * i.e. if no_proxy contains "example.com:1880", then "mqtt://example.com" should be excluded
+    * Does not consider NPM proxy configuration at all
+        * i.e. if npm_config_proxy is set, then it should be used
+        * i.e. if npm_config_https_proxy is set, then it should be used
+        * i.e. if npm_config_http_proxy is set, then it should be used
+        * i.e. if npm_config_no_proxy is set, then it should be used
+    * Doesn't consider https_proxy or HTTPS_PROXY
+        * i.e. if https_proxy is set, then it should be used
+        * i.e. if HTTPS_PROXY is set, then it should be used
+        * i.e. incorrectly uses HTTP_PROXY 'http://http-proxy' when the url is 'https://example'
+    * Incorrectly prioritises HTTP_PROXY over http_proxy. HTTP_PROXY is not always supported or recommended
+        * i.e. if HTTP_PROXY and http_proxy are both set, then http_proxy should be used
+        * Use lowercase form. HTTP_PROXY is not always supported or recommended
+    * doesn't consider all_proxy or ALL_PROXY
+        * i.e. if all_proxy is set, then it should be used
+        * i.e. if ALL_PROXY is set, then it should be used
+        * 
+        * 
+This implementation is based on the following sources:
+    * https://about.gitlab.com/blog/2021/01/27/we-need-to-talk-no-proxy/ (GitLab)
+    * https://www.npmjs.com/package/proxy-from-env (MIT License)
+
+This implementation proposal follows the following rules:
+    * Support the following PROTOCOL_proxys
+        * i.e. http_proxy, https_proxy, mqtt_proxy, ws_proxy, wss_proxy, mqtt_proxy, mqtts_proxy
+    * Support all_proxy
+        * i.e. if all_proxy is set, then all URLs will be proxied
+    * Use comma-separated hostname[:port] values for no_proxy.
+        * no_proxy should contain a comma-separated list of domain extensions proxy should not be used for
+        * Each value may include optional whitespace.
+        * port is optional and is inferred if the protocol has a default port (supports http, https, mqtt, ws, wss, mqtt, mqtts)
+        * Use * to match all hosts
+    * Support .example (host suffix)
+    * Support sub.example (host sub domain)
+    * Upper case forms of *_PROXY are supported but not recommended
+    * Lower case forms of *_proxy will take precedence over upper case forms
+    * Does not perform DNS lookups or use regular expressions
+    * Does not perform validation on the *_proxy urls
+    * Does not support CIDR block matching
+    * Support IPv6 matching
+******/
+
+/* eslint max-statements:0 */
+'use strict';
+
+const assert = require('assert');
+
+const { getProxyForUrl } = require("nr-test-utils").require('@node-red/nodes/core/network/lib/proxyHelper')
+
+/**
+ * Defines a test case that checks whether getProxyForUrl(input) === expected.
+ * @param {object} env - The environment variables to use for the test
+ * @param {*} expected - The expected result
+ * @param {*} input - The input to test
+ * @param {import('../../../../../packages/node_modules/@node-red/nodes/core/network/lib/proxyHelper').ProxyOptions} options - The options to use for getProxyForUrl
+ */
+function testProxyUrl(env, expected, input, options) {
+    assert(typeof env === 'object' && env !== null);
+    // Copy object to make sure that the in param does not get modified between
+    // the call of this function and the use of it below.
+    env = JSON.parse(JSON.stringify(env));
+
+    var title = 'getProxyForUrl(' + JSON.stringify(input) + ')' +
+        ' === ' + JSON.stringify(expected);
+
+    // Save call stack for later use.
+    var stack = {};
+    Error.captureStackTrace(stack, testProxyUrl);
+    // Only use the last stack frame because that shows where this function is
+    // called, and that is sufficient for our purpose. No need to flood the logs
+    // with an uninteresting stack trace.
+    stack = stack.stack.split('\n', 2)[1];
+
+    it(title, function () {
+        var actual;
+        // runWithEnv(env, function () {
+        //     actual = getProxyForUrl(input, options);
+        // });
+        options = options || {};
+        options.env = options.env || env || process.env;
+        options.mode = options.mode || 'strict';
+        actual = getProxyForUrl(input, options);
+        if (expected === actual) {
+            return;  // Good!
+        }
+        try {
+            assert.strictEqual(expected, actual); // Create a formatted error message.
+            // Should not happen because previously we determined expected !== actual.
+            throw new Error('assert.strictEqual passed. This is impossible!');
+        } catch (e) {
+            // Use the original stack trace, so we can see a helpful line number.
+            e.stack = e.message + stack;
+            throw e;
+        }
+    });
+}
+
+describe('Proxy Helper', function () {
+    describe('No proxy variables', function () {
+        const env = {};
+        testProxyUrl(env, '', 'http://example.com');
+        testProxyUrl(env, '', 'https://example.com');
+        testProxyUrl(env, '', 'ftp://example.com');
+    });
+
+    describe('Invalid URLs', function () {
+        const env = {};
+        env.ALL_PROXY = 'http://unexpected.proxy';
+        testProxyUrl(env, '', 'bogus');
+        testProxyUrl(env, '', '//example.com');
+        testProxyUrl(env, '', '://example.com');
+        testProxyUrl(env, '', '://');
+        testProxyUrl(env, '', '/path');
+        testProxyUrl(env, '', '');
+        testProxyUrl(env, '', 'ws:');
+        testProxyUrl(env, '', 'wss:');
+        testProxyUrl(env, '', 'mqtt:');
+        testProxyUrl(env, '', 'mqtts:');
+        testProxyUrl(env, '', 'http:');
+        testProxyUrl(env, '', 'http:/');
+        testProxyUrl(env, '', 'http://');
+        testProxyUrl(env, '', 'prototype://');
+        testProxyUrl(env, '', 'hasOwnProperty://');
+        testProxyUrl(env, '', '__proto__://');
+        testProxyUrl(env, '', undefined);
+        testProxyUrl(env, '', null);
+        testProxyUrl(env, '', {});
+        testProxyUrl(env, '', { host: 'x', protocol: 1 });
+        testProxyUrl(env, '', { host: 1, protocol: 'x' });
+    });
+    describe('Proxy options', function () {
+        describe('allowUpperCase:false should prevent *_PROXY being returned', function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://upper-case-proxy';
+            env.HTTPS_PROXY = 'https://upper-case-proxy';
+            testProxyUrl(env, '', 'http://example', { lowerCaseOnly: true });
+            testProxyUrl(env, '', 'https://example', { lowerCaseOnly: true });
+            testProxyUrl(env, 'http://upper-case-proxy', 'http://example'); //returns lower case due to precedence
+            testProxyUrl(env, 'https://upper-case-proxy', 'https://example'); //returns lower case due to precedence
+        });
+
+        describe('favourLowerCase:false should cause *_PROXY to being used before *_proxy', function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://upper-case-proxy';
+            env.http_proxy = 'http://lower-case-proxy';
+            testProxyUrl(env, 'http://upper-case-proxy', 'http://example', { favourUpperCase: true });
+            testProxyUrl(env, 'http://lower-case-proxy', 'http://example'); // lowercase takes precedence by default
+        });
+
+        describe('includeNpm:false should not return npm_config_*_proxy env vars', function () {
+            const env = {};
+            env.npm_config_http_proxy = 'http://npm-proxy';
+            testProxyUrl(env, '', 'http://example', { excludeNpm: true });
+            testProxyUrl(env, 'http://npm-proxy', 'http://example'); // lowercase takes precedence by default
+        });
+
+        describe('legacyMode:true should process urls proxy in node-red < v3.1 compatibility mode', function () {
+            const env = {};
+            // legacy mode does not consider npm_config_*_proxy
+            env.npm_config_http_proxy = 'http://npm-proxy';
+            testProxyUrl(env, '', 'http://example/1', { mode: 'legacy' });
+            testProxyUrl(env, 'http://npm-proxy', 'http://example/1');
+
+            // legacy mode does not consider all_proxy
+            env.all_proxy = 'http://all-proxy';
+            testProxyUrl(env, '', 'http://example/2', { mode: 'legacy' });
+            testProxyUrl(env, 'http://npm-proxy', 'http://example/2');
+
+            // legacy mode does not consider *_proxy
+            env.npm_config_http_proxy = null;
+            env.http_proxy = 'http://http-proxy';
+            env.no_proxy = 'example';
+            testProxyUrl(env, '', 'http://example/3a', { mode: 'legacy' });
+            testProxyUrl(env, '', 'http://example/3b');
+
+            // legacy mode does not consider protocol_proxy for https urls and uses http_proxy
+            env.https_proxy = 'https://https-proxy';
+            env.no_proxy = '';
+            testProxyUrl(env, 'http://http-proxy', 'https://example/4', { mode: 'legacy' });
+            testProxyUrl(env, 'https://https-proxy', 'https://example/4');
+
+            // legacy mode favours UPPER_CASE over lower_case
+            env.HTTP_PROXY = 'http://http-proxy-upper';
+            env.no_proxy = '';
+            testProxyUrl(env, 'http://http-proxy-upper', 'http://example/5', { mode: 'legacy' });
+            testProxyUrl(env, 'http://http-proxy', 'http://example/5');
+        });
+    });
+
+    describe('http_proxy and HTTP_PROXY', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://http-proxy';
+
+        testProxyUrl(env, '', 'https://example');
+        testProxyUrl(env, 'http://http-proxy', 'http://example');
+        testProxyUrl(env, 'http://http-proxy', new URL('http://example'));
+
+        // eslint-disable-next-line camelcase
+        env.http_proxy = 'http://priority';
+        testProxyUrl(env, 'http://priority', 'http://example');
+    });
+
+    describe('http_proxy with non-sensical value', function () {
+        const env = {};
+        // Crazy values should be passed as-is. It is the responsibility of the
+        // one who launches the application that the value makes sense.
+        // TODO: Should we be stricter and perform validation?
+        env.HTTP_PROXY = 'Crazy \n!() { ::// }';
+        testProxyUrl(env, 'Crazy \n!() { ::// }', 'http://wow');
+
+        // The implementation assumes that the HTTP_PROXY environment variable is
+        // somewhat reasonable, and if the scheme is missing, it is added.
+        // Garbage in, garbage out some would say...
+        env.HTTP_PROXY = 'crazy without colon slash slash';
+        testProxyUrl(env, 'http://crazy without colon slash slash', 'http://wow');
+    });
+
+    describe('https_proxy and HTTPS_PROXY', function () {
+        const env = {};
+        // Assert that there is no fall back to http_proxy
+        env.HTTP_PROXY = 'http://unexpected.proxy';
+        testProxyUrl(env, '', 'https://example');
+
+        env.HTTPS_PROXY = 'http://https-proxy';
+        testProxyUrl(env, 'http://https-proxy', 'https://example');
+
+        // eslint-disable-next-line camelcase
+        env.https_proxy = 'http://priority';
+        testProxyUrl(env, 'http://priority', 'https://example');
+    });
+
+    describe('ftp_proxy', function () {
+        const env = {};
+        // Something else than http_proxy / https, as a sanity check.
+        env.FTP_PROXY = 'http://ftp-proxy';
+
+        testProxyUrl(env, 'http://ftp-proxy', 'ftp://example');
+        testProxyUrl(env, '', 'ftps://example');
+    });
+
+    describe('ws_proxy', function () {
+        const env = {};
+        // Something else than http_proxy / https, as a sanity check.
+        env.ws_proxy = 'ws://ws-proxy';
+
+        testProxyUrl(env, 'ws://ws-proxy', 'ws://example1');
+        testProxyUrl(env, '', 'wss://example2');
+    });
+
+    describe('mqtt_proxy', function () {
+        const env = {};
+        // Something else than http_proxy / https, as a sanity check.
+        env.mqtt_proxy = 'mqtt://mqtt-proxy';
+        env.no_proxy = 'mqtt://mqtt-proxy';
+
+        testProxyUrl(env, 'mqtt://mqtt-proxy', 'mqtt://example1');
+        testProxyUrl(env, '', 'mqtts://example2');
+    });
+
+    describe('all_proxy', function () {
+        const env = {};
+        env.ALL_PROXY = 'http://catch-all';
+        testProxyUrl(env, 'http://catch-all', 'https://example');
+
+        // eslint-disable-next-line camelcase
+        env.all_proxy = 'http://priority';
+        testProxyUrl(env, 'http://priority', 'https://example');
+    });
+
+    describe('all_proxy without scheme', function () {
+        const env = {};
+        env.ALL_PROXY = 'noscheme';
+        testProxyUrl(env, 'http://noscheme', 'http://example');
+        testProxyUrl(env, 'https://noscheme', 'https://example');
+
+        // The module does not impose restrictions on the scheme.
+        testProxyUrl(env, 'bogus-scheme://noscheme', 'bogus-scheme://example');
+
+        // But the URL should still be valid.
+        testProxyUrl(env, '', 'bogus');
+    });
+
+    describe('no_proxy empty', function () {
+        const env = {};
+        env.HTTPS_PROXY = 'http://proxy';
+
+        // NO_PROXY set but empty.
+        env.NO_PROXY = '';
+        testProxyUrl(env, 'http://proxy', 'https://example1');
+
+        // No entries in NO_PROXY (comma).
+        env.NO_PROXY = ',';
+        testProxyUrl(env, 'http://proxy', 'https://example2');
+
+        // No entries in NO_PROXY (whitespace).
+        env.NO_PROXY = ' ';
+        testProxyUrl(env, 'http://proxy', 'https://example3');
+
+        // No entries in NO_PROXY (multiple whitespace / commas).
+        env.NO_PROXY = ',\t,,,\n,  ,\r';
+        testProxyUrl(env, 'http://proxy', 'https://example4');
+    });
+
+    describe('no_proxy=example (single host)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = 'example';
+        testProxyUrl(env, '', 'http://example');
+        testProxyUrl(env, '', 'http://example:80');
+        testProxyUrl(env, '', 'http://example:0');
+        testProxyUrl(env, '', 'http://example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://sub.example');
+        testProxyUrl(env, 'http://proxy', 'http://prefexample');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, 'http://proxy', 'http://a.b.example');
+        testProxyUrl(env, 'http://proxy', 'http://host/example');
+    });
+
+    describe('no_proxy=sub.example (subdomain)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = 'sub.example';
+        testProxyUrl(env, '', 'http://sub.example');
+        testProxyUrl(env, '', 'http://sub.example:80');
+        testProxyUrl(env, '', 'http://sub.example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://example');
+        testProxyUrl(env, 'http://proxy', 'http://example:80');
+        testProxyUrl(env, 'http://proxy', 'http://example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://bus.example');
+        testProxyUrl(env, 'http://proxy', 'http://bus.example:80');
+        testProxyUrl(env, 'http://proxy', 'http://bus.example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://prefexample');
+        testProxyUrl(env, 'http://proxy', 'http://a.b.example');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, 'http://proxy', 'http://host/example');
+    });
+
+    describe('no_proxy=example:80 (host + port)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = 'example:80';
+        testProxyUrl(env, '', 'http://example');
+        testProxyUrl(env, '', 'http://example:80');
+        testProxyUrl(env, '', 'http://example:0');
+        testProxyUrl(env, 'http://proxy', 'http://example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://sub.example');
+        testProxyUrl(env, 'http://proxy', 'http://prefexample');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, 'http://proxy', 'http://a.b.example');
+    });
+
+    describe('no_proxy=.example (host suffix)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = '.example';
+        testProxyUrl(env, 'http://proxy', 'http://example');
+        testProxyUrl(env, 'http://proxy', 'http://example:80');
+        testProxyUrl(env, 'http://proxy', 'http://example:1337');
+        testProxyUrl(env, '', 'http://sub.example');
+        testProxyUrl(env, '', 'http://sub.example:80');
+        testProxyUrl(env, '', 'http://sub.example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://prefexample');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, '', 'http://a.b.example');
+    });
+
+    describe('no_proxy=*', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+        env.NO_PROXY = '*';
+        testProxyUrl(env, '', 'http://example.com');
+    });
+
+    describe('no_proxy=*.example (host suffix with *.)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = '*.example';
+        testProxyUrl(env, 'http://proxy', 'http://example');
+        testProxyUrl(env, 'http://proxy', 'http://example:80');
+        testProxyUrl(env, 'http://proxy', 'http://example:1337');
+        testProxyUrl(env, '', 'http://sub.example');
+        testProxyUrl(env, '', 'http://sub.example:80');
+        testProxyUrl(env, '', 'http://sub.example:1337');
+        testProxyUrl(env, 'http://proxy', 'http://prefexample');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, '', 'http://a.b.example');
+    });
+
+    describe('no_proxy=*example (substring suffix)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = '*example';
+        const t = getProxyForUrl('http://example', { env });
+        testProxyUrl(env, '', 'http://example');
+        testProxyUrl(env, '', 'http://example:80');
+        testProxyUrl(env, '', 'http://example:1337');
+        testProxyUrl(env, '', 'http://sub.example');
+        testProxyUrl(env, '', 'http://sub.example:80');
+        testProxyUrl(env, '', 'http://sub.example:1337');
+        testProxyUrl(env, '', 'http://prefexample');
+        testProxyUrl(env, '', 'http://a.b.example');
+        testProxyUrl(env, 'http://proxy', 'http://example.no');
+        testProxyUrl(env, 'http://proxy', 'http://host/example');
+    });
+
+    describe('no_proxy=.*example (arbitrary wildcards are NOT supported)',
+        function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://proxy';
+
+            env.NO_PROXY = '.*example';
+            testProxyUrl(env, 'http://proxy', 'http://example');
+            testProxyUrl(env, 'http://proxy', 'http://sub.example');
+            testProxyUrl(env, 'http://proxy', 'http://prefexample');
+            testProxyUrl(env, 'http://proxy', 'http://x.prefexample');
+            testProxyUrl(env, 'http://proxy', 'http://a.b.example');
+        });
+
+    describe('no_proxy=[::1],[::2]:80,10.0.0.1,10.0.0.2:80 (IP addresses)',
+        function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://proxy';
+
+            env.NO_PROXY = '[::1],[::2]:80,10.0.0.1,10.0.0.2:80';
+            testProxyUrl(env, '', 'http://[::1]/');
+            testProxyUrl(env, '', 'http://[::1]:80/');
+            testProxyUrl(env, '', 'http://[::1]:1337/');
+
+            testProxyUrl(env, '', 'http://[::2]/');
+            testProxyUrl(env, '', 'http://[::2]:80/');
+            testProxyUrl(env, 'http://proxy', 'http://[::2]:1337/');
+
+            testProxyUrl(env, '', 'http://10.0.0.1/');
+            testProxyUrl(env, '', 'http://10.0.0.1:80/');
+            testProxyUrl(env, '', 'http://10.0.0.1:1337/');
+
+            testProxyUrl(env, '', 'http://10.0.0.2/');
+            testProxyUrl(env, '', 'http://10.0.0.2:80/');
+            testProxyUrl(env, 'http://proxy', 'http://10.0.0.2:1337/');
+
+            testProxyUrl(env, 'http://proxy', 'http://10.0.0.3/');
+            testProxyUrl(env, 'http://proxy', 'http://10.0.0.3:80/');
+            testProxyUrl(env, 'http://proxy', 'http://10.0.0.3:1337/');
+        });
+
+    describe('no_proxy=127.0.0.1/32 (CIDR is NOT supported)', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = '127.0.0.1/32';
+        testProxyUrl(env, 'http://proxy', 'http://127.0.0.1');
+        testProxyUrl(env, 'http://proxy', 'http://127.0.0.1/32');
+    });
+
+    describe('no_proxy=127.0.0.1 does NOT match localhost', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+
+        env.NO_PROXY = '127.0.0.1';
+        testProxyUrl(env, '', 'http://127.0.0.1');
+        // We're not performing DNS queries, so this shouldn't match.
+        testProxyUrl(env, 'http://proxy', 'http://localhost');
+    });
+
+    describe('no_proxy with protocols that have a default port', function () {
+        const env = {};
+        env.MQTT_PROXY = 'http://mqtt';
+        env.MQTTS_PROXY = 'https://m_q_t_t_s_proxy';
+        env.WS_PROXY = 'http://ws';
+        env.WSS_PROXY = 'http://wss';
+        env.HTTP_PROXY = 'http://http';
+        env.HTTPS_PROXY = 'http://https';
+        env.GOPHER_PROXY = 'http://gopher';
+        env.FTP_PROXY = 'http://ftp';
+        env.ALL_PROXY = 'http://all';
+
+        env.NO_PROXY = 'xxx:21,xxx:70,xxx:80,xxx:443,xxx:1880,xxx:8880';
+
+        testProxyUrl(env, '', 'http://xxx');
+        testProxyUrl(env, '', 'http://xxx:80');
+        testProxyUrl(env, 'http://http', 'http://xxx:1337');
+
+        testProxyUrl(env, '', 'ws://xxx');
+        testProxyUrl(env, '', 'ws://xxx:80');
+        testProxyUrl(env, 'http://ws', 'ws://xxx:1337');
+
+        testProxyUrl(env, '', 'https://xxx');
+        testProxyUrl(env, '', 'https://xxx:443');
+        testProxyUrl(env, 'http://https', 'https://xxx:1337');
+
+        testProxyUrl(env, '', 'wss://xxx');
+        testProxyUrl(env, '', 'wss://xxx:443');
+        testProxyUrl(env, 'http://wss', 'wss://xxx:1337');
+
+        testProxyUrl(env, '', 'gopher://xxx');
+        testProxyUrl(env, '', 'gopher://xxx:70');
+        testProxyUrl(env, 'http://gopher', 'gopher://xxx:1337');
+
+        testProxyUrl(env, '', 'ftp://xxx');
+        testProxyUrl(env, '', 'ftp://xxx:21');
+        testProxyUrl(env, 'http://ftp', 'ftp://xxx:1337');
+
+        testProxyUrl(env, '', 'mqtt://xxx');
+        testProxyUrl(env, '', 'mqtt://xxx:1880');
+        testProxyUrl(env, 'http://mqtt', 'mqtt://xxx:1337');
+
+        testProxyUrl(env, 'http://mqtt', 'mqtt://yyy');
+        testProxyUrl(env, 'http://mqtt', 'mqtt://yyy:1880');
+
+        testProxyUrl(env, 'http://all', 'unknown://xxx');
+        testProxyUrl(env, 'http://all', 'unknown://xxx:1234');
+    });
+
+    describe('no_proxy should not be case-sensitive', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+        env.NO_PROXY = 'XXX,YYY,ZzZ';
+
+        testProxyUrl(env, '', 'http://xxx');
+        testProxyUrl(env, '', 'http://XXX');
+        testProxyUrl(env, '', 'http://yyy');
+        testProxyUrl(env, '', 'http://YYY');
+        testProxyUrl(env, '', 'http://ZzZ');
+        testProxyUrl(env, '', 'http://zZz');
+    });
+
+    describe('no_proxy should accept space separated entries', function () {
+        const env = {};
+        env.HTTP_PROXY = 'http://proxy';
+        env.NO_PROXY = 'X X X,Y Y Y,Z z Z';
+
+        testProxyUrl(env, '', 'http://x x x');
+        testProxyUrl(env, '', 'http://X X X');
+        testProxyUrl(env, '', 'http://y y y');
+        testProxyUrl(env, '', 'http://Y Y Y');
+        testProxyUrl(env, '', 'http://Z z Z');
+        testProxyUrl(env, '', 'http://z Z z');
+    });
+
+    describe('NPM proxy configuration', function () {
+        describe('npm_config_http_proxy should work', function () {
+            const env = {};
+            // eslint-disable-next-line camelcase
+            env.npm_config_http_proxy = 'http://http-proxy';
+
+            testProxyUrl(env, '', 'https://example');
+            testProxyUrl(env, 'http://http-proxy', 'http://example');
+
+            // eslint-disable-next-line camelcase
+            env.npm_config_http_proxy = 'http://priority';
+            testProxyUrl(env, 'http://priority', 'http://example');
+        });
+        // eslint-disable-next-line max-len
+        describe('npm_config_http_proxy should take precedence over HTTP_PROXY and npm_config_proxy', function () {
+            const env = {};
+            // eslint-disable-next-line camelcase
+            env.npm_config_http_proxy = 'http://http-proxy';
+            // eslint-disable-next-line camelcase
+            env.npm_config_proxy = 'http://unexpected-proxy';
+            env.HTTP_PROXY = 'http://unexpected-proxy';
+
+            testProxyUrl(env, 'http://http-proxy', 'http://example');
+        });
+        describe('npm_config_https_proxy should work', function () {
+            const env = {};
+            // eslint-disable-next-line camelcase
+            env.npm_config_http_proxy = 'http://unexpected.proxy';
+            testProxyUrl(env, '', 'https://example');
+
+            // eslint-disable-next-line camelcase
+            env.npm_config_https_proxy = 'http://https-proxy';
+            testProxyUrl(env, 'http://https-proxy', 'https://example');
+
+            // eslint-disable-next-line camelcase
+            env.npm_config_https_proxy = 'http://priority';
+            testProxyUrl(env, 'http://priority', 'https://example');
+        });
+        // eslint-disable-next-line max-len
+        describe('npm_config_https_proxy should take precedence over HTTPS_PROXY and npm_config_proxy', function () {
+            const env = {};
+            // eslint-disable-next-line camelcase
+            env.npm_config_https_proxy = 'http://https-proxy';
+            // eslint-disable-next-line camelcase
+            env.npm_config_proxy = 'http://unexpected-proxy';
+            env.HTTPS_PROXY = 'http://unexpected-proxy';
+
+            testProxyUrl(env, 'http://https-proxy', 'https://example');
+        });
+        describe('npm_config_proxy should work', function () {
+            const env = {};
+            // eslint-disable-next-line camelcase
+            env.npm_config_proxy = 'http://http-proxy';
+            testProxyUrl(env, 'http://http-proxy', 'http://example');
+            testProxyUrl(env, 'http://http-proxy', 'https://example');
+
+            // eslint-disable-next-line camelcase
+            env.npm_config_proxy = 'http://priority';
+            testProxyUrl(env, 'http://priority', 'http://example');
+            testProxyUrl(env, 'http://priority', 'https://example');
+        });
+        // eslint-disable-next-line max-len
+        describe('HTTP_PROXY and HTTPS_PROXY should take precedence over npm_config_proxy', function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://http-proxy';
+            env.HTTPS_PROXY = 'http://https-proxy';
+            // eslint-disable-next-line camelcase
+            env.npm_config_proxy = 'http://unexpected-proxy';
+            testProxyUrl(env, 'http://http-proxy', 'http://example');
+            testProxyUrl(env, 'http://https-proxy', 'https://example');
+        });
+        describe('npm_config_no_proxy should work', function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://proxy';
+            // eslint-disable-next-line camelcase
+            env.npm_config_no_proxy = 'example';
+
+            testProxyUrl(env, '', 'http://example');
+            testProxyUrl(env, 'http://proxy', 'http://otherwebsite');
+        });
+        // eslint-disable-next-line max-len
+        describe('npm_config_no_proxy should take precedence over NO_PROXY', function () {
+            const env = {};
+            env.HTTP_PROXY = 'http://proxy';
+            env.NO_PROXY = 'otherwebsite';
+            // eslint-disable-next-line camelcase
+            env.npm_config_no_proxy = 'example';
+
+            testProxyUrl(env, '', 'http://example');
+            testProxyUrl(env, 'http://proxy', 'http://otherwebsite');
+        });
+    });
+});