node js无法处理sns事件消息内容

Question

我正在尝试从节点 js lambda 项目中的 SNS 事件中的消息中获取内容

这里是处理消息的代码

exports.handler = (event, context, callback) => {

var message = event.Records[0].Sns.Message;
console.log('Message received from SNS:', message); 

message.Events.forEach(element => {
    console.log(element);

   });
};

示例事件：

{ 
 "Records": 
  [ 
    { 
     "EventSource": "aws:sns",
     "EventVersion": "1.0",
     "EventSubscriptionArn": "",
     "Sns": 
       { 
         "Type": "Notification",
         "MessageId": "bc86f105-c320",
         "TopicArn": "arn:aws:sns:ewerwrewrw",
         "Subject": "dwqweq23234",
         "Message": 
           {
           "Events":
             [
               {"EventTimestamp":"2018-03-16T10:51:22Z"},
               {"EventTimestamp":"2018-03-16T10:51:22Z"}
             ],
            "EventDocVersion":"2014-08-15"
           },
          "Timestamp": "2018-03-16T10:51:22.691Z",
          "SignatureVersion": "1",
          "Signature": "",
          "SigningCertUrl": "",
          "UnsubscribeUrl": "",
          "MessageAttributes": {} 
      } 
    } 
  ]
 }

这是我在 CloudWatch 日志中得到的：

Message received from SNS: { "Events": [ {"EventTimestamp":"2018-03-16T10:51:22Z"}, {"EventTimestamp":"2018-03-16T10:51:22Z"} ], "EventDocVersion":"2014-08-15" }

TypeError: Cannot read property 'forEach' of undefined at exports.handler

为什么我无法在事件中解析 'Events' 内部消息对象？

Answer 1

尝试 message["Events"].forEach 而不是 message.Events 可能会工作并检查天气属性存在 using.Actually message.Events 如果您在控制台中获得与您提到的相同的对象，这应该有效，但您至少可以通过检查属性来避免错误。 ----编辑----if(message && message.hasOwnProperty('Events'))

if(message && message.hasOwnProperty('Events')){
   message.Events.forEach(element => {
    console.log(element);

   });
}

我认为您收到的消息是空白的，请先尝试打印它，因为我在下面的浏览器中尝试正常工作：

var obj={ 
 "Records": 
  [ 
    { 
     "EventSource": "aws:sns",
     "EventVersion": "1.0",
     "EventSubscriptionArn": "",
     "Sns": 
       { 
         "Type": "Notification",
         "MessageId": "bc86f105-c320",
         "TopicArn": "arn:aws:sns:ewerwrewrw",
         "Subject": "dwqweq23234",
         "Message": 
           {
           "Events":
             [
               {"EventTimestamp":"2018-03-16T10:51:22Z"},
               {"EventTimestamp":"2018-03-16T10:51:22Z"}
             ],
            "EventDocVersion":"2014-08-15"
           },
          "Timestamp": "2018-03-16T10:51:22.691Z",
          "SignatureVersion": "1",
          "Signature": "",
          "SigningCertUrl": "",
          "UnsubscribeUrl": "",
          "MessageAttributes": {} 
      } 
    } 
  ]
 };
var fun1 = function(event, context, callback){

var message = event.Records[0].Sns.Message;
console.log('Message received from SNS:', message); 
console.log("starting")
message["Events"].forEach(element => {
    console.log(element);

   });
};
fun1(obj,'',function(){console.log("uu")})

Answer 2

在我修复后工作：

var message = event.Records[0].Sns.Message;

var msgJson = JSON.parse(message);

msgJson["Events"].forEach(element => { .....

node js无法处理sns事件消息内容

node js can't process sns event message content

javascript

node.js

amazon-sns

aws-lambda