1  'use strict';
  2  
  3  var parseUrl = require('url').parse;
  4  
  5  var DEFAULT_PORTS = {
  6    ftp: 21,
  7    gopher: 70,
  8    http: 80,
  9    https: 443,
 10    ws: 80,
 11    wss: 443,
 12  };
 13  
 14  var stringEndsWith = String.prototype.endsWith || function(s) {
 15    return s.length <= this.length &&
 16      this.indexOf(s, this.length - s.length) !== -1;
 17  };
 18  
 19  /**
 20   * @param {string|object} url - The URL, or the result from url.parse.
 21   * @return {string} The URL of the proxy that should handle the request to the
 22   *  given URL. If no proxy is set, this will be an empty string.
 23   */
 24  function getProxyForUrl(url) {
 25    var parsedUrl = typeof url === 'string' ? parseUrl(url) : url || {};
 26    var proto = parsedUrl.protocol;
 27    var hostname = parsedUrl.host;
 28    var port = parsedUrl.port;
 29    if (typeof hostname !== 'string' || !hostname || typeof proto !== 'string') {
 30      return '';  // Don't proxy URLs without a valid scheme or host.
 31    }
 32  
 33    proto = proto.split(':', 1)[0];
 34    // Stripping ports in this way instead of using parsedUrl.hostname to make
 35    // sure that the brackets around IPv6 addresses are kept.
 36    hostname = hostname.replace(/:\d*$/, '');
 37    port = parseInt(port) || DEFAULT_PORTS[proto] || 0;
 38    if (!shouldProxy(hostname, port)) {
 39      return '';  // Don't proxy URLs that match NO_PROXY.
 40    }
 41  
 42    var proxy =
 43      getEnv('npm_config_' + proto + '_proxy') ||
 44      getEnv(proto + '_proxy') ||
 45      getEnv('npm_config_proxy') ||
 46      getEnv('all_proxy');
 47    if (proxy && proxy.indexOf('://') === -1) {
 48      // Missing scheme in proxy, default to the requested URL's scheme.
 49      proxy = proto + '://' + proxy;
 50    }
 51    return proxy;
 52  }
 53  
 54  /**
 55   * Determines whether a given URL should be proxied.
 56   *
 57   * @param {string} hostname - The host name of the URL.
 58   * @param {number} port - The effective port of the URL.
 59   * @returns {boolean} Whether the given URL should be proxied.
 60   * @private
 61   */
 62  function shouldProxy(hostname, port) {
 63    var NO_PROXY =
 64      (getEnv('npm_config_no_proxy') || getEnv('no_proxy')).toLowerCase();
 65    if (!NO_PROXY) {
 66      return true;  // Always proxy if NO_PROXY is not set.
 67    }
 68    if (NO_PROXY === '*') {
 69      return false;  // Never proxy if wildcard is set.
 70    }
 71  
 72    return NO_PROXY.split(/[,\s]/).every(function(proxy) {
 73      if (!proxy) {
 74        return true;  // Skip zero-length hosts.
 75      }
 76      var parsedProxy = proxy.match(/^(.+):(\d+)$/);
 77      var parsedProxyHostname = parsedProxy ? parsedProxy[1] : proxy;
 78      var parsedProxyPort = parsedProxy ? parseInt(parsedProxy[2]) : 0;
 79      if (parsedProxyPort && parsedProxyPort !== port) {
 80        return true;  // Skip if ports don't match.
 81      }
 82  
 83      if (!/^[.*]/.test(parsedProxyHostname)) {
 84        // No wildcards, so stop proxying if there is an exact match.
 85        return hostname !== parsedProxyHostname;
 86      }
 87  
 88      if (parsedProxyHostname.charAt(0) === '*') {
 89        // Remove leading wildcard.
 90        parsedProxyHostname = parsedProxyHostname.slice(1);
 91      }
 92      // Stop proxying if the hostname ends with the no_proxy host.
 93      return !stringEndsWith.call(hostname, parsedProxyHostname);
 94    });
 95  }
 96  
 97  /**
 98   * Get the value for an environment variable.
 99   *
100   * @param {string} key - The name of the environment variable.
101   * @return {string} The value of the environment variable.
102   * @private
103   */
104  function getEnv(key) {
105    return process.env[key.toLowerCase()] || process.env[key.toUpperCase()] || '';
106  }
107  
108  exports.getProxyForUrl = getProxyForUrl;