使用AWS NodeJS Lambda读取AWS dynamoDB中的过滤数据

debugcn 发表于 Dev

斯蒂芬·格兰隆（StéphaneGRILLON）

我想将元素从DynamoDB获取到我的NodeJS AWS Lambda。我想由“所有者”列选择，但不起作用。我尝试对“ id”列使用相同的语法，但结果没问题。在dynamoDB中添加索引？在哪里？

'use strict';

var AWS = require('aws-sdk');
var documentClient = new AWS.DynamoDB.DocumentClient({'region': 'eu-west-1'}); 

exports.handler = function(event, context, callback) {
  
  console.log(JSON.stringify(event));

  const claims = event.requestContext.authorizer.claims;
  const username = claims['cognito:username'];
  
  var params = {
    TableName : "tp-exam",
      Key: {
        owner: username 
      }
  };
  
    documentClient.get(params, function(err, data){
      if (err) {
      console.log("Error", err);
      const errResponse = {
        statusCode: 500,
        headers: {
          "Access-Control-Allow-Origin": "*"
        },
        body: JSON.stringify({ Error: 500, device : "DynamoDB"})
      };
      callback(null, errResponse);
    } else {
      console.log("Success", data.Item);
      const response = {
        statusCode: 200,
        headers: {
          "Access-Control-Allow-Origin": "*"
        },
        body: JSON.stringify(data.Item)
      };
        callback(null, response);
    }
        
    });

};

我的错误是：

ValidationException: The provided key element does not match the schema
    at Request.extractError (/var/runtime/node_modules/aws-sdk/lib/protocol/json.js:52:27)
    at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:106:20)
    at Request.emit (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:78:10)
    at Request.emit (/var/runtime/node_modules/aws-sdk/lib/request.js:688:14)
    at Request.transition (/var/runtime/node_modules/aws-sdk/lib/request.js:22:10)
    at AcceptorStateMachine.runTo (/var/runtime/node_modules/aws-sdk/lib/state_machine.js:14:12)
    at /var/runtime/node_modules/aws-sdk/lib/state_machine.js:26:10
    at Request.<anonymous> (/var/runtime/node_modules/aws-sdk/lib/request.js:38:9)
    at Request.<anonymous> (/var/runtime/node_modules/aws-sdk/lib/request.js:690:12)
    at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:116:18) {
  code: 'ValidationException',
  time: 2021-03-01T21:46:40.263Z,
  requestId: 'C7UHG8354A92SGP2T4FRRFU4GFVV4KQNSO5AEMVJF66Q9ASUAAJG',
  statusCode: 400,
  retryable: false,
  retryDelay: 32.73628085995177
}

Balu vyamajala

我们需要一个全局二级索引来获取或查询备用键。

并使用GSI进行查询，我们需要使用查询api。

let docClient = new AWS.DynamoDB.DocumentClient();

documentClient.query(
  {
    TableName: "tp-exam",
    IndexName: "owner-index",
    KeyConditionExpression: "#owner_attr = :ownerVal",
    ExpressionAttributeValues: {
      ":ownerVal": "John",
    },
    ExpressionAttributeNames: {
      "#owner_attr": "owner",
    },
  },
  function (err, data) {
    console.log("err", err, "data", data);
  }
);

owner 是保留关键字，因此，我们需要使用ExpressAttributeNames替换为实际属性。

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