amazon-dynamodb - 错误 InvalidParameterType : Expected params. 项目 ['pid'] 成为 DynamoDB 中的结构

Question

注意:所有这些都发生在 DynamoDB 的本地实例上。

这是我用来从 DynamoDB Shell 创建表的代码:

var params = {
    TableName: "TABLE-NAME",
    KeySchema: [
        { AttributeName: "pid", 
          KeyType: "HASH"
        }
    ],
    AttributeDefinitions: [
        { AttributeName: "pid",
          AttributeType: "S"
        }
    ],
    ProvisionedThroughput: {
        ReadCapacityUnits: 1,
        WriteCapacityUnits: 1
    }
};


dynamodb.createTable(params, function(err, data) {
    if (err)
        console.log(JSON.stringify(err, null, 2));
    else
        console.log(JSON.stringify(data, null, 2));
});

这是被调用以将元素添加到数据库中的函数(在 node.js 中):

function(request, response) {
  params = {
    TableName: 'TABLE-NAME',
    Item: {
      pid: 'abc123'
    }
  };
  console.log(params);
  dynamodb.putItem(params, function(err, data) {
    if (err)
      console.log(JSON.stringify(err, null, 2));
    else
      console.log(JSON.stringify(data, null, 2));
  });
}

我得到的输出是:

{ TableName: 'TABLE-NAME',
  Item: { pid: 'abc123' } }   // THIS IS PARAMS
{
  "message": "There were 7 validation errors:\n* InvalidParameterType: Expected params.Item['pid'] to be a structure\n* UnexpectedParameter: Unexpected key '0' found in params.Item['pid']\n* UnexpectedParameter: Unexpected key '1' found in params.Item['pid']\n* UnexpectedParameter: Unexpected key '2' found in params.Item['pid']\n* UnexpectedParameter: Unexpected key '3' found in params.Item['pid']\n* UnexpectedParameter: Unexpected key '4' found in params.Item['pid']\n* UnexpectedParameter: Unexpected key '5' found in params.Item['pid']",
  "code": "MultipleValidationErrors",
  "errors": [
    {
      "message": "Expected params.Item['pid'] to be a structure",
      "code": "InvalidParameterType",
      "time": "2015-11-26T15:51:33.932Z"
    },
    {
      "message": "Unexpected key '0' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.933Z"
    },
    {
      "message": "Unexpected key '1' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.933Z"
    },
    {
      "message": "Unexpected key '2' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.933Z"
    },
    {
      "message": "Unexpected key '3' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.933Z"
    },
    {
      "message": "Unexpected key '4' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.934Z"
    },
    {
      "message": "Unexpected key '5' found in params.Item['pid']",
      "code": "UnexpectedParameter",
      "time": "2015-11-26T15:51:33.934Z"
    }
  ],
  "time": "2015-11-26T15:51:33.944Z"
}

我不明白为什么或如何获取键 0、1、2、3、4 和 5，而它们在上一行打印时不存在。

另外，如何修复错误 Expected params.Item['pid'] to be a structure ?我已将其声明为字符串并尝试存储字符串!

其他注意事项:
当我在 shell 上运行它时，我在函数中使用的相同代码工作得很好。我还包括了 aws-sdk 并根据需要对其进行了配置:

var AWS = require('aws-sdk');
AWS.config.region = 'us-east-1';
AWS.config.endpoint = 'http://localhost:8000/'
var dynamodb = new AWS.DynamoDB();

Answer 1

putItem() AWS.DynamoDB 上的方法类(class)期待 params.Item要格式化为 AttributeValue 表示的对象。这意味着你必须改变这个:

params = {
  TableName: 'TABLE-NAME',
  Item: {
    pid: 'abc123'
  }
};

进入这个:

params = {
  TableName: 'TABLE-NAME',
  Item: {
    pid: {
      S: 'abc123'
    }
  }
};

如果你想使用原生 javascript 对象，你应该使用 AWS.DynamoDB.DocumentClient 类，它会自动将 Javascript 类型编码到 DynamoDB AttributeValues 上，如下所示:

字符串 -> S

号码 -> N

bool 值 -> bool 值

空 -> 空

数组 -> L

对象 -> M

缓冲区、文件、Blob、ArrayBuffer、DataView 和 JavaScript 类型数组 -> B

它提供了 put() 方法，委托(delegate)给 AWS.DynamoDB.putItem() .