我正在尝试使用 nodejs 从 mongodb 集合中检索数据，但我必须请求两次才能获得正确的信息

Question

This is my code: I have to request twice to get the data.这是我的代码：我必须请求两次才能获取数据。 Any problem?任何问题？ Thanks谢谢

var http = require('http');
var url = require('url');
var input = "";
const MongoClient = require('mongodb').MongoClient;
const url2 = "mongodb+srv://ramaty01:password@cluster0-hi4fv.mongodb.net/test?retryWrites=true&w=majority";

http.createServer(function(req, res){
  if (req.url === '/favicon.ico') {
    res.writeHead(200, {'Content-Type': 'image/x-icon'} );
    res.end();
    console.log('favicon requested');
    return;
  }
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.write(
    "<html><head><title> MongoDB and NodeJS</title></head>" + 
    "<body><h1> COMPANY STOCK STICKER</h1><form>" + 
      "<input type='radio' id='company' name='types' value='company' required>" +
      "<label for='company'>Company Name</label><br>" + 
      "<input type='radio' id='stock' name='types' value='stock'>" + 
      "<label for='stock'>Stock Ticker</label><br><br>" +
      "<label for='txt'>Input: </label>" +
      "<input type='text' id='txt' name='txt'><br><br>" +
      "<input type='submit' value='Submit'>" +
    "</form><div id='output'></div></body></html>"
  );
  var qobj = url.parse(req.url, true).query;

  //var items;
  mong(qobj);
  res.write(input);
  res.end()
  input= "";
}).listen(8080);

function mong(qobj){

MongoClient.connect(url2, { useUnifiedTopology: true }, function(err, db) {
    if(err) { console.log("Connection err: " + err); return; }
    var dbo = db.db("Company");
    var coll = dbo.collection('companies');
    var query;
    var inp = qobj.txt;
    if (qobj.types == "company") {
      query = { "company_name" : inp};
    } else if (qobj.types == "stock") {
      query = { "stock_ticker" : inp};
    }
    var s = coll.find(query,{projection: {"company_name":1, "stock_ticker":1, "_id":0}}).stream();

    s.on("data", function(item) {input = input + item.company_name + " " + item.stock_ticker;});
    s.on("end", function() {console.log("end of data");  db.close();});
  });
}

Answer 1

First of all, I recommend that you immediately change your monogdb atlas password, and that you be more careful next time you're posting anything with sensitive information online.首先，我建议您立即更改您的monogdb atlas 密码，并且下次您在网上发布任何包含敏感信息的内容时要更加小心。

With that being said, having worked with mongodb Atlas for sometime now, I've noticed that connection normally takes sometime, and that introduces some noticeable lag the fist time you fire up your server.话虽如此，在与 mongodb Atlas 合作一段时间后，我注意到连接通常需要一些时间，并且在您启动服务器时会引入一些明显的延迟。 That is probably what is happening, and since from your code I can't see evidence that your local server is waiting for this connection to happen before "serving" requests to your browser, there is no guarantee of the succession of events To test this hypothesis, I suggest you wait for sometime before accessing the local server.这可能是正在发生的事情，并且由于从您的代码中我看不到证据表明您的本地服务器正在等待此连接发生，然后再向您的浏览器“提供”请求，因此无法保证事件的连续性要测试这一点假设，我建议您在访问本地服务器之前等待一段时间。 This can be easily solved using an async function, or chaining a promise before starting your local server这可以使用异步 function 或在启动本地服务器之前链接 promise 轻松解决

我正在尝试使用 nodejs 从 mongodb 集合中检索数据，但我必须请求两次才能获得正确的信息

问题描述

1 个解决方案

解决方案1
1 2020-04-23 01:08:18

我正在尝试使用 nodejs 从 mongodb 集合中检索数据，但我必须请求两次才能获得正确的信息

问题描述

1 个解决方案

解决方案1 1 2020-04-23 01:08:18

解决方案1
1 2020-04-23 01:08:18