无法使用cheerio读取未定义（读取'statusCode'）Nodejs的属性

Question

我试图为这个有趣的请求获取网页的标题，cheerio 面临这个问题无法读取未定义的属性（读取'statusCode'）但是当我运行尝试使用 static 值单独运行时它可以工作

任何人都可以帮助确定我在代码中所做的错误吗？

这是我的代码

var request = require("request");
var cheerio = require("cheerio");

jsonData = [
  { Domain: "bar-n-ranch.com" },
  { Domain: "barcelona-enabled.com" },
  { Domain: "barefootamelia.com" },
  { Domain: "barmranch.com" },
  { Domain: "barnstablepatriot.com" },
  { Domain: "barrieapartmentrentalsonline.com" },
  { Domain: "basquehomes.com" },
  { Domain: "bassmaster.com" },
  { Domain: "basswoodresort.com" },
];

function fetchTitle(url, onComplete = null) {
  request(url, function (error, response, body) {
    var output = url; // default to URL

    if (!error && response.statusCode === 200) {
      var $ = cheerio.load(body);
      console.log(`URL = ${url}`);

      var title = $("head > title").text().trim();
      console.log(`Title = ${title}`);

      output = `[${title}] (${url})`;
    } else {
      console.log(`Error = ${error}, code = ${response.statusCode}`);
    }

    console.log(`output = ${output} \n\n`);

    if (onComplete) onComplete(output);
  });
}

jsonData.forEach(function (table) {
  var tableName = table.Domain;
  var URL = "http://" + tableName;
  fetchTitle(URL);
});

当传递像 fetchtitle("https://www.googlecom") 这样的值时，它可以工作，但是当我尝试循环 JSON 数据时出现错误

错误堆栈跟踪 ^

TypeError: Cannot read properties of undefined (reading 'statusCode')
    at Request._callback (C:\1\naveen\Project\Final\scrap example\test.js:29:56)
    at self.callback (C:\1\naveen\Project\Final\scrap example\node_modules\request\request.js:185:22)
    at Request.emit (node:events:390:28)
    at Request.onRequestError (C:\1\naveen\Project\Final\scrap example\node_modules\request\request.js:877:8)
    at ClientRequest.emit (node:events:390:28)
    at Socket.socketErrorListener (node:_http_client:447:9)
    at Socket.emit (node:events:390:28)
    at emitErrorNT (node:internal/streams/destroy:157:8)
    at emitErrorCloseNT (node:internal/streams/destroy:122:3)

非常感谢您提前

Answer 1

有时，当您在服务器上循环执行多个请求时，套接字可能会挂起（忙于其他请求）或服务器无法将请求排队，这可能导致请求没有响应。 对此的最佳解决方案是，在访问其属性之前，您必须首先检查来自请求的响应 object。

    if (!error && (response && response.statusCode) === 200) {
        var $ = cheerio.load(body);
        console.log(`URL = ${url}`);

        var title = $("head > title").text().trim();
        console.log(`Title = ${title}`);

        output = `[${title}] (${url})`;
    }
    else {
        console.log(`Error = ${error}, code = ${response && response.statusCode}`);
    }