Question

我对承诺的理解并不完美所以我不确定哪种代码是处理错误和异常情况的正确方法。

请帮助我正确编写代码。

第一。尝试 - 抓住续集器的promise.reject

async function doGetAdminList(adminName) {

      let adminList;
      try {
        adminList = await sequelize.query(
          sqls.GET_ADMIN_LIST,
          { replacements: { adminName: adminName }, type: sequelize.QueryTypes.SELECT }
        );
      } catch (e) {
        return Promise.reject({status:500, message: "SQL Error" });
      }    

      if (!adminList || !Object.keys(adminList).length) {
        log.info('\nadminList not found :\n');
        return Promise.reject({status:400, message: 'adminList not found.' })
      } 

      return adminList;
    }

为此，我想知道try-catch是否可以捕获续集器的promise.catch（）。

第二。不要处理续集器的promise.reject

async function doGetAdminList(adminName) {
          let adminList;
          adminList = await sequelize.query(
              sqls.GET_ADMIN_LIST,
              { replacements: { adminName: adminName }, type: sequelize.QueryTypes.SELECT }
          );

          if (!adminList || !Object.keys(adminList).length) {
            log.info('\nadminList not found :\n');
            return Promise.reject({status:400, message: 'adminList not found.' })
          } 

          return adminList;
        }

为此，我想知道sequelizer的promise.reject（）是否可以传递调用函数并在promise.catch（）中捕获调用者。

以下续集使用功能将在快递功能下方使用。

adminController.js

const jwtAuth = require('../common/jwtAuth.js');

exports.getAdminList = function (req, res) {
  res.setHeader("Content-Type", "application/json; charset=utf-8");

  if (!req.body.adminName) {
    return res.status(400).json({ message: 'adminName is empty.' });
  }

  jwtAuth(req.headers.accesstoken)
  .then((decoded) => {
    worker = decoded.loginName;
    return doGetAdminList(adminName);
  })
  .then((adminList) => {
    log.info("getAdminList() finish");
    res.status(200).json(adminList);
  })
  .catch(e => {
    log.error(e);
    return res.status(e.status).json(e);
  });
};

jwtAuth.js也是承诺函数。

const jwt = require('jsonwebtoken');
module.exports = async function verifyJwt(token) {
  return await new Promise((resolve, reject) => {
    if (!token) {
      reject({status:401, message:'Empty token'});
      return;
    }

    jwt.verify(token,"dipa",function(err, decoded){
      if(err) {
        reject({status:401, message:'TokenExpiredError'});
      } else {
        resolve(decoded);
      }
    });
  }); 
}

Answer 1

无需使用＆＃39; async＆＃39;如果您的函数返回一个promise，因为async函数返回Promise。

我的意思是var somethink = await doSomethink()的结果不是承诺它是一个对象，而是因为你从async函数返回它，它返回为Promise.resolve(somethink )。

所以你的＆＃39; jwtAuth.js＆＃39;没有

就更好了

const jwt = require('jsonwebtoken');
module.exports = function verifyJwt(token) {
  return new Promise((resolve, reject) => {
    if (!token) {
      reject({status:401, message:'Empty token'});
      return;
    }

    jwt.verify(token,"dipa",function(err, decoded){
      if(err) {
        reject({status:401, message:'TokenExpiredError'});
      } else {
        resolve(decoded);
      }
    });
  }); 
}

同样适用于

function doGetAdminList(adminName) {

  let adminList;

  return sequelize.query(
    sqls.GET_ADMIN_LIST, {
      replacements: {
        adminName: adminName
      },
      type: sequelize.QueryTypes.SELECT
    }
  ).catch((e)=> {
    //here you catch you sequelize error which can be anything
    //you can either catch and throw a new Error
    log.info('\nadminList not found :\n');
    throw Error({
      status: 500,
      message: "SQL Error"
    })
  })

}

关于getAdminList和最后的catch。

如果jwtAuth或doGetAdminList引发错误.catch，则会收到错误。

如果在doGetAdminList .catch您sequelize.query sequelize error catch，则const jwtAuth = require('../common/jwtAuth.js'); exports.getAdminList = function (req, res) { res.setHeader("Content-Type", "application/json; charset=utf-8"); if (!req.body.adminName) { res.status(400).json({ message: 'adminName is empty.' }); } jwtAuth(req.headers.accesstoken) .then((decoded) => { worker = decoded.loginName; return doGetAdminList(adminName); }) .then((adminList) => { log.info("getAdminList() finish"); res.status(200).json(adminList); }) .catch(e => { //the message with mess "SQL Error" will travel here. log.error(e); res.status(e.status).json(e); }); };会在.catch(function(e) { log.info('\nadminList not found :\n'); throw e; })前往getAdminList。但是，如果您想处理错误并重新抛出，则可能出现错误。

async/await

添加，如果您不想更改错误，但是您想记录错误并将其重新抛出，可以重新抛出错误

exports.getAdminList = async function(req, res) {
  res.setHeader("Content-Type", "application/json; charset=utf-8");

  if (!req.body.adminName)
    res.status(400).json({message: 'adminName is empty.'});

  try {

    let decoded = await jwtAuth(req.headers.accesstoken)
    worker = decoded.loginName;

    let adminList = await doGetAdminList(req.body.adminName);
    log.info("getAdminList() finish");

    res.status(200).json(adminList);

  } catch (e) {
     //the message with mess "SQL Error" will travel here.
    log.error(e);
    res.status(e.status).json(e);
  }

};

此外，如果你想{ field: 'CustomerRef', value: '2083', operator: '=' }与try { timer1.Enabled = false; //Set interval and tick-handler from designer pauseTimer.Enabled = false; pauseTimer.Enabled = true; } catch (Exception ex) { Logging.LogFatal("Scroll event capture error: ", ex); }

一起做

try
{
    //Assume that this is the refreshtimer. In the Tick-eventhandler 
    //you reset interval to default refresh intervals
    timer1.Interval = 60000;
    timer1.Enabled = false;
    timer1.Enabled = true;

}
catch (Exception ex)
{
    Logging.LogFatal("Scroll event capture error: ", ex);
}

处理promise.reject到try-catch或promise.catch

1 个答案: