javascript-node.js解决承诺并返回值

我使用Microsoft Bot框架提出了一个“简单的” PoC Bot.我以tutorial为基础进行扩展.

我有一些针对差异意图的基本功能(例如,问候语,再见等),其中一个具有更多逻辑(reqstatus).

简单的(即greeting.js)可以很好地返回答案,而复杂的则不能(reqstatus.js).在独立脚本中运行reqstatus.js的主要代码(不带第一个“ const getReqStatus =(entity)=> {”).

server.js(主)->参见“如果(意图){”中的调用…

const getFeelings = require('./intents/feelings.js')
const getGoodbyes = require('./intents/goodbyes.js')
const getGreetings = require('./intents/greetings.js')
const getHelp = require('./intents/help.js')
const getReqStatus = require('./intents/reqstatus.js')
... 
const bot = new builder.UniversalBot(connector)

// Intents based on deFinitions on recast
const INTENTS = {
  feelings: getFeelings,
  goodbyes: getGoodbyes,
  greetings: getGreetings,
  help: getHelp,
  reqstatus: getReqStatus,
}

// Event when Message received
bot.dialog('/', (session) => {
  recastClient.textRequest(session.message.text)
  .then(res => {
  const intent = res.intent()
  const entity = res.get('request_number')

  console.log(`UserName: ${session.message.user.name}`)
  console.log(`Msg: ${session.message.text}`)
  console.log(`Intent: ${intent.slug}`) 

  if (intent) {
    INTENTS[intent.slug](entity)
    .then(res => session.send(res)) 
    .catch(err => session.send(err))
  }
  })
  .catch(() => session.send('Sorry I didn\'t get that. '))
  })
  ...

greetings.js->返回字符串ok

const getGreetings = () => {
  const answers = ['Hi, my name is SuperBot. Nice to meet you!', ] 
  return Promise.resolve((answers))
  }
module.exports = getGreetings

reqstatus.js->不返回任何东西

const getReqStatus = (entity) => {
  var request = require('request');
  var request_number = entity.toLowerCase()
  var output = [];


  // Processing
  var lineReader = require('readline').createInterface({
  input: fs.createReadStream('netreqs.csv')
  }); 

  lineReader.on('line', function (line) {
  var jsonFromLine = {};
  var linesplit = line.split(';');
  jsonFromLine.req = linesplit[0];
  jsonFromLine.req_count = linesplit[1];
  jsonFromLine.req_type = linesplit[2];
  //...
  var req_lowever = jsonFromLine.req.toLowerCase()
  if (req_lowever == request_number) {
     output.push( `Your request ${jsonFromLine.req} was received`);    
  // simplified
  }
  });

  // Output
  lineReader.on('close', function (line) {
  if (output == '') {
    output.push( `I was not able to find a request like ${request_number}.`);
    }
  console.log(output); // list output 
  return Promise.resolve(output); 
   });
  }
module.exports = getReqStatus

我还尝试将getReqStatus放在函数中,但这也没有用.
经过大量的尝试和谷歌搜索,我仍然陷于困境,并想问这里的专家.非常感谢.

解决方法:

我认为问题在于您的getReqStatus并未真正返回任何内容.在示例getGreetings函数中,您实际上是在返回Promise.resolve(answers)作为该函数的返回值.

但是,在您的getReqStatus函数中,您只需设置一个监听器lineReader close事件：

lineReader.on('close', function (line) {
if (output == '') {
    output.push( `I was not able to find a request like ${request_number}.`);
}
    console.log(output); // list output 
    return Promise.resolve(output); 
});

您将在匿名回调函数内部返回一个已解决的Promise,该函数将作为第二个参数传递给lineReader.on().那不是getReqStatus函数本身的返回值,因此getReqStatus不会按预期返回任何内容.

正如您所说,该函数的代码可以作为独立代码正常运行,只是因为它正确设置了侦听器并执行了它必须要做的事情.但是,当包装在函数中时,该代码不会返回Promise.

您需要返回一个Promise,该Promise在close处理程序上包装lineReader.,例如：

function getReqStatus(){
//...code

return new Promise( function(resolve , reject ){
    lineReader.on('close', function (line) {
        if (output == '') {
            output.push( `I was not able to find a request like ${request_number}.`);
        }
        console.log(output); // list output
        return resolve(output);
        });
    });
}

我之所以这样说是因为我真的不知道这段代码是否可以工作,我对Microsoft Bot框架没有任何经验,也没有与readline模块一起使用.但是,即使这不能解决您的问题,我希望它可以帮助您稍微理解为什么您的函数不返回Promise以及如何解决它.

javascript-node.js解决承诺并返回值

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