以交互方式从控制台读取价值

Question

我想用一些控制台扩展来创建一个简单的服务器http服务器.我找到了从命令行数据中读取的代码段.

  var i = rl.createInterface(process.stdin, process.stdout, null);
  i.question('Write your name: ', function(answer) {
    console.log('Nice to meet you> ' + answer);
    i.close();
    process.stdin.destroy();

  });

好好反复问问题,我不能简单地使用while(done) { }循环？如果服务器在提问时接收输出也很好,它会破坏该行.

Answer 1

你不能做一个"while(done)"循环,因为这需要阻塞输入,node.js不喜欢这样做.

而是设置每次输入内容时调用的回调:

var stdin = process.openStdin();

stdin.addListener("data", function(d) {
    // note:  d is an object, and when converted to a string it will
    // end with a linefeed.  so we (rather crudely) account for that  
    // with toString() and then trim() 
    console.log("you entered: [" + 
        d.toString().trim() + "]");
  });

Answer 2

我为此目的使用了另一个API ..

var readline = require('readline');
var rl = readline.createInterface(process.stdin, process.stdout);
rl.setPrompt('guess> ');
rl.prompt();
rl.on('line', function(line) {
    if (line === "right") rl.close();
    rl.prompt();
}).on('close',function(){
    process.exit(0);
});

这允许循环提示直到答案为止right.它也提供了很好的小控制台.你可以找到详细信息@ http://nodejs.org/api/readline.html#readline_example_tiny_cli

Answer 3

自12'以来,Readline API发生了很大的变化.该文档显示了从标准流中捕获用户输入的有用示例:

const readline = require('readline');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

rl.question('What do you think of Node.js? ', (answer) => {
  console.log('Thank you for your valuable feedback:', answer);
  rl.close();
});

更多信息在这里.

Answer 4

请使用readline-sync,这样您就可以使用同步控制台而无需回调.甚至可以使用密码:

var favFood = read.question('What is your favorite food? ', {
  hideEchoBack: true // The typed text on screen is hidden by `*` (default). 
});

Answer 5

我相信这值得一个现代的async-await答案,假设使用node> = 7.x.

答案仍然使用,ReadLine::question但包装它,以便while (done) {}可能,这是OP明确要求的东西.

var cl = readln.createInterface( process.stdin, process.stdout );
var question = function(q) {
    return new Promise( (res, rej) => {
        cl.question( q, answer => {
            res(answer);
        })
    });
};

然后是一个示例用法

(async function main() {
    var answer;
    while ( answer != 'yes' ) {
        answer = await question('Are you sure? ');
    }
    console.log( 'finally you are sure!');
})();

导致以下对话

Are you sure? no
Are you sure? no
Are you sure? yes
finally you are sure!

Answer 6

@rob answer大多数时候都会工作,但是它可能不会像你期望的那样长时间输入.

这就是你应该使用的:

const stdin = process.openStdin();
let content = '';

stdin.addListener('data', d => {
  content += d.toString();
});

stdin.addListener('end', () => {
  console.info(`Input: ${content}`);
});

解释为什么此解决方案有效:

addListener('data') 就像一个缓冲区,回调将在它满或/和它的输入结束时被调用.

长输入怎么样？单个'data'回调是不够的,因此您将在两个或更多部分中分配输入.这通常不方便.

addListener('end')当stdin阅读器完成阅读我们的输入后会通知我们.由于我们一直存储以前的数据,现在我们可以一起阅读和处理它们.

Answer 7

我建议使用Inquirer，因为它提供了常见的交互式命令行用户界面的集合。

const inquirer = require('inquirer');

const questions = [{
  type: 'input',
  name: 'name',
  message: "What's your name?",
}];

const answers = await inquirer.prompt(questions);
console.log(answers);

Answer 8

这是一个例子：

const stdin = process.openStdin()

process.stdout.write('Enter name: ')

stdin.addListener('data', text => {
  const name = text.toString().trim()
  console.log('Your name is: ' + name)

  stdin.pause() // stop reading
})

输出：

Enter name: bob
Your name is: bob