在 nodejs 中发出 rl.close() 后，readline 不会停止行读取 [英] readline doesn't stop line reading after rl.close() emit in nodejs

问题描述

我有以下文件，我想逐行读取并在找到nameserver 8.8.8.8"后停止读取.

I have the following file I want to read line by line and stop reading it once I have found "nameserver 8.8.8.8".

nameserver 8.8.8.8
nameserver 45.65.85.3
nameserver 40.98.3.3

我正在使用 nodejs 和 readline 模块来这样做

I am using nodejs and the readline module to do so

const readline = require('readline');
const fs = require('fs');

function check_resolv_nameserver(){
  // flag indicates whether namerserver_line was found or not
  var nameserver_flag = false;

  const rl = readline.createInterface({
    input: fs.createReadStream('file_to_read.conf')
  });

  rl.on('line', (line) => {
    console.log(`Line from file: ${line}`);
    if (line === 'nameserver 8.8.8.8'){
      console.log('Found the right file. Reading lines should stop here.');
      nameserver_flag = true;
      rl.close();
    }
  });

  rl.on('close', function(){
    if (nameserver_flag === true){
      console.log('Found nameserver 8.8.8.8');
    }
    else {
      console.log('Could not find nameserver 8.8.8.8');
    }
  });
}

check_resolv_nameserver();

由于我在读取第一个匹配项后立即使用 rl.close() 发出关闭事件，因此我希望我的代码仅读取第一行，然后停止进一步读取.但是我的输出看起来像这样

Since I emit a close event with rl.close() as soon as I read the first match, I would expect my Code to read only the first line and then stop reading further. But instead my output looks like this

Line from file: nameserver 8.8.8.8
Found the right file. Reading lines should stop here.
Found nameserver 8.8.8.8
Line from file: nameserver 45.65.85.3
Line from file: nameserver 40.98.3.3

如何在第一场比赛后让 readline 停止并让我继续做其他事情?

How can I make readline stop after first match and let me proceed with a something else?

推荐答案

对于那些无法让 linereader 停止的人，请执行以下操作(在您的 readline 回调中):

for those of you who can't make the linereader stop, do this (in your readline callback):

lineReader.close()
lineReader.removeAllListeners()

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