var ip = req.headers['x-forwarded-for'] || req.socket.remoteAddress 

对于Linux和macOS，如果你想通过同步方式获取你的IP地址，试试这个:

var ips = require('child_process').execSync("ifconfig | grep inet | grep -v inet6 | awk '{gsub(/addr:/,\"\");print $2}'").toString().trim().split("\n");
console.log(ips);

结果会是这样的:

['192.168.3.2', '192.168.2.1']

这是我的变体，允许以可移植的方式获得IPv4和IPv6地址:

/**
 * Collects information about the local IPv4/IPv6 addresses of
 * every network interface on the local computer.
 * Returns an object with the network interface name as the first-level key and
 * "IPv4" or "IPv6" as the second-level key.
 * For example you can use getLocalIPs().eth0.IPv6 to get the IPv6 address
 * (as string) of eth0
 */
getLocalIPs = function () {
    var addrInfo, ifaceDetails, _len;
    var localIPInfo = {};
    //Get the network interfaces
    var networkInterfaces = require('os').networkInterfaces();
    //Iterate over the network interfaces
    for (var ifaceName in networkInterfaces) {
        ifaceDetails = networkInterfaces[ifaceName];
        //Iterate over all interface details
        for (var _i = 0, _len = ifaceDetails.length; _i < _len; _i++) {
            addrInfo = ifaceDetails[_i];
            if (addrInfo.family === 'IPv4') {
                //Extract the IPv4 address
                if (!localIPInfo[ifaceName]) {
                    localIPInfo[ifaceName] = {};
                }
                localIPInfo[ifaceName].IPv4 = addrInfo.address;
            } else if (addrInfo.family === 'IPv6') {
                //Extract the IPv6 address
                if (!localIPInfo[ifaceName]) {
                    localIPInfo[ifaceName] = {};
                }
                localIPInfo[ifaceName].IPv6 = addrInfo.address;
            }
        }
    }
    return localIPInfo;
};

下面是同一个函数的CoffeeScript版本:

getLocalIPs = () =>
    ###
    Collects information about the local IPv4/IPv6 addresses of
      every network interface on the local computer.
    Returns an object with the network interface name as the first-level key and
      "IPv4" or "IPv6" as the second-level key.
    For example you can use getLocalIPs().eth0.IPv6 to get the IPv6 address
      (as string) of eth0
    ###
    networkInterfaces = require('os').networkInterfaces();
    localIPInfo = {}
    for ifaceName, ifaceDetails of networkInterfaces
        for addrInfo in ifaceDetails
            if addrInfo.family=='IPv4'
                if !localIPInfo[ifaceName]
                    localIPInfo[ifaceName] = {}
                localIPInfo[ifaceName].IPv4 = addrInfo.address
            else if addrInfo.family=='IPv6'
                if !localIPInfo[ifaceName]
                    localIPInfo[ifaceName] = {}
                localIPInfo[ifaceName].IPv6 = addrInfo.address
    return localIPInfo

console.log(getLocalIPs())的示例输出

{ lo: { IPv4: '127.0.0.1', IPv6: '::1' },
  wlan0: { IPv4: '192.168.178.21', IPv6: 'fe80::aa1a:2eee:feba:1c39' },
  tap0: { IPv4: '10.1.1.7', IPv6: 'fe80::ddf1:a9a1:1242:bc9b' } }

这里有一个可能是最干净、最简单的答案，没有依赖关系，而且适用于所有平台。

const { lookup } = require('dns').promises;
const { hostname } = require('os');

async function getMyIPAddress(options) {
  return (await lookup(hostname(), options))
    .address;
}

类似于其他答案，但更简洁:

'use strict';

const interfaces = require('os').networkInterfaces();

const addresses = Object.keys(interfaces)
  .reduce((results, name) => results.concat(interfaces[name]), [])
  .filter((iface) => iface.family === 'IPv4' && !iface.internal)
  .map((iface) => iface.address);

根据注释，以下是当前版本Node.js的工作原理:

var os = require('os');
var _ = require('lodash');

var ip = _.chain(os.networkInterfaces())
  .values()
  .flatten()
  .filter(function(val) {
    return (val.family == 'IPv4' && val.internal == false)
  })
  .pluck('address')
  .first()
  .value();

上面一个答案的注释缺少对values()的调用。看起来os.networkInterfaces()现在返回一个对象而不是数组。