从 Node JS 连接 Redshift 时无法返回任何值

Posted 2023-03-30

【中文标题】从 Node JS 连接 Redshift 时无法返回任何值

【英文标题】：Can't return any value while connecting Redshift from Node JS

【发布时间】：2021-06-22 08:39:44

【问题描述】：

下面的代码连接到Redshift数据库却返回一个空响应，即使响应会显示在console.log中，为什么？

index.js

   
const config = 
  user: 'user',
  database: 'database',
  password: 'password',
  port: port,
  host: 'hostname',
;
var response = [];
console.log('Before Connection');
exports.handler =  function index(event, context, callback) 
  var redshiftClient = new Redshift(config, rawConnection:true);
    redshiftClient.connect(function(err)
    console.log('After Connection');
    if(err) throw err;
    else
      redshiftClient.query('SELECT * FROM customer', raw: true, function(err, data)
        if(err) throw err;
        else
            response = data;
            console.log(data);
            redshiftClient.close();
            return response;
            
        
         
      );
    
  );
 
  return response;
;

【参考方案1】：

我使用了 Promise 概念，它确实为我正确返回了响应。 示例 JSON "user_id": "1001"

var Redshift = require('node-redshift');
   
const config = 
  user: 'user',
  database: 'database',
  password: 'password',
  port: port,
  host: 'hostname',
;

// The values passed in to the options object will be the difference between a connection pool and raw connection
var redshiftClient = new Redshift(config, rawConnection:true);


exports.handler =  async (event) => 
return new Promise(function(resolve, reject)

redshiftClient.connect(function(err)
    if(err) throw err;
    else
      redshiftClient.parameterizedQuery('SELECT * FROM customer where user_id = $1', [event.user_id], raw: true, function(err, data)
        if(err) throw reject(err);
        else
          resolve(data);
          redshiftClient.close();
        
      );
    
  ); 
);

;