node.js - 使用 AWS Lambda NodeJS 时无法返回结果

Question

我正在尝试在 AWS Lambda 上实现一个简单的 Node Js 函数来从 dynamoDB 查询数据。我将此 lambda 函数挂接到我的 API 网关，但当我访问 API url 时没有看到任何结果。

//Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region
AWS.config.update({region: 'us-east-1'});

// Create DynamoDB service object
var b = new AWS.DynamoDB({apiVersion: '2012-08-10'});

var params = {
   ExpressionAttributeNames: {
    "#devicetimestamp": "timestamp"
  },
  ExpressionAttributeValues: {
    ':unitID': {S: 'arena-MXHGMYzBBP5F6jztnLUdCL'},
    ':dtimestamp' : {S: '1582920096000'}
   },
 KeyConditionExpression: 'id = :unitID and #devicetimestamp > :dtimestamp',
 TableName: 'IoTdata2'
};

b.query(params, function(err, results) {
    if (err) {
        console.error("Unable to query. Error:", JSON.stringify(err, null, 2));
    } else {
        console.log("Query succeeded.");
        console.log(JSON.stringify(results));
    }
});

当我看到 console.log(JSON.stringify(results)); 的结果时，代码工作正常；当我使用事件处理程序时

//Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region
AWS.config.update({region: 'us-east-1'});

// Create DynamoDB service object
var b = new AWS.DynamoDB({apiVersion: '2012-08-10'});

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

var params = {
   ExpressionAttributeNames: {
    "#devicetimestamp": "timestamp"
  },
  ExpressionAttributeValues: {
    ':unitID': {S: 'arena-MXHGMYzBBP5F6jztnLUdCL'},
    ':dtimestamp' : {S: '1582920096000'}
   },
 KeyConditionExpression: 'id = :unitID and #devicetimestamp > :dtimestamp',
 TableName: 'IoTdata2'
};

b.query(params, function(err, results) {
    if (err) {
        console.error("Unable to query. Error:", JSON.stringify(err, null, 2));
        callback(err);
    } else {
        console.log("Query succeeded.");
        console.log(JSON.stringify(results));
       callback(null, results);
    }
});
};

```i don't see any response in API URL.I am new to nodeJS, Any suggestions will be greatly appreciated. Thanks

Answer 1

由于您要通过 API 网关，因此您需要满足来自 lambda 的特定响应契约，请尝试这样做:

const response = {
  statusCode: 200, // need a status code
  body: JSON.stringify(results) // and a string body
}

callback(null, response)

这里有更多信息:TUTORIAL: Build a Hello World API with Lambda Proxy Integration - Amazon API Gateway