我们可以在node js中检查这段代码

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

let addresses = [];

for (var k in interfaces) {

    for (var k2 in interfaces[k]) {

        const address = interfaces[k][k2];

        if ( (address.family === 'IPv4' || address.family === 'IPv6')  && 
            !address.internal) {

            addresses.push(address.address);

        }
    }
}
console.log(addresses);

你可以保持DRY，只使用支持IPv4和IPv6的node-ipware。

安装:

npm install ipware

在你的app.js或中间件中:

var getIP = require('ipware')().get_ip;
app.use(function(req, res, next) {
    var ipInfo = getIP(req);
    console.log(ipInfo);
    // { clientIp: '127.0.0.1', clientIpRoutable: false }
    next();
});

它将尽最大努力获取用户的IP地址或返回127.0.0.1，以表明它无法确定用户的IP地址。查看README文件中的高级选项。

你可以像这样快速获取用户Ip

req.ip

在这个例子中，我们获取了用户的Ip，然后用req.ip把它发回给用户

app.get('/', (req, res)=> { 
    res.send({ ip : req.ip})
    
})

我使用这个ipv4格式

req.connection.remoteAddress.split(':').slice(-1)[0]

请求。headers['x-forwarded-for'] || request.connection.remoteAddress . headers['x-forwarded-for'

如果有x-forward -for报头，则使用它，否则使用. remoteaddress属性。

The x-forwarded-for header is added to requests that pass through load balancers (or other types of proxy) set up for HTTP or HTTPS (it's also possible to add this header to requests when balancing at a TCP level using proxy protocol). This is because the request.connection.remoteAddress the property will contain the private IP address of the load balancer rather than the public IP address of the client. By using an OR statement, in the order above, you check for the existence of an x-forwarded-for header and use it if it exists otherwise use the request.connection.remoteAddress.

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

请注意，有时您可以在req.headers['x-forwarded-for']中获得多个IP地址。此外，并不总是设置x-forward -for报头，这可能会抛出错误。

该字段的一般格式为:

x-forward -for: client, proxy1, proxy2, proxy3

其中的值是一个逗号+空格分隔的IP地址列表，最左边是原始客户端，每个传递请求的后续代理添加接收请求的IP地址。在本例中，请求通过proxy1、proxy2和proxy3传递。Proxy3显示为请求的远程地址。

这是Arnav Gupta提出的解决方案，Martin在下面的评论中为未设置x-forward -for的情况提出了修复建议:

var ip = (req.headers['x-forwarded-for'] || '').split(',').pop().trim() || 
         req.socket.remoteAddress

使用现代JS的建议:

仅在设置时处理x-forward -for，如果设置了，则取第一个地址 其他参数使用可选链接(?.)

const parseIp = (req) =>
    req.headers['x-forwarded-for']?.split(',').shift()
    || req.socket?.remoteAddress

console.log(parseIp(req))
// => 127.0.0.1