节点“req 未定义”

当我尝试启动以下脚本时：

var http = require("http");

http.createServer(function(request, response) {
  response.writeHead(200, {"Content-Type": "text/plain"});
  response.write("Hello World");
  response.end();
}).listen(8000);

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

console.log(ip)

我收到以下错误：

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
ReferenceError: req is not defined
    at Object.<anonymous> (/home/ubuntu/IPDeliverer/server.js:9:10)
    at Module._compile (module.js:441:26)
    at Object..js (module.js:459:10)
    at Module.load (module.js:348:32)
    at Function._load (module.js:308:12)
    at Array.0 (module.js:479:10)
    at EventEmitter._tickCallback (node.js:192:41)

我的第一个猜测是，缺少一些模块，所以我安装了以下模块，如下所示：

npm install req

然后我添加了以下行

var req = require("./node_modules/req/node_modules/request");

但它仍然不起作用。有什么建议 ？

您已将请求命名为request, not req，每个回调都有它自己的request，所以像这样检查回调之外的IP是没有意义的。使用request在回调中改为：

var http = require("http");

http.createServer(function(request, response) {
  response.writeHead(200, {"Content-Type": "text/plain"});
  response.write("Hello World");
  response.end();

  var ip = request.headers['x-forwarded-for'] || request.connection.remoteAddress;

  console.log(ip)
}).listen(8000);