Dynamodb alexa 查询不调用数据项

Question

我正在创建一项技能，我想调用 alexa 在特定日期和时间阅读不同的项目。我目前的 table 设置如下：日期|时间|状态

日期设置为主键，时间设置为排序键。我将日期和时间设置为 ASK 中的槽值，我可以看到这些值正在传递。我还确保我的日期和时间格式在 dynamodb 中是正确的。

我的问题是当我调用 alexa 并询问某个日期和时间的状态时，我无法让 alexa 以与该日期和时间对应的状态响应。

谁能帮我解决这个问题？或者告诉我哪里出错了，我会在下面插入我的代码。

const awsSDK = require('aws-sdk');
const updatedincident = 'updatedincident';
const docClient = new awsSDK.DynamoDB.DocumentClient();

var AWSregion = 'us-east-1';  // us-east-1
var AWS = require('aws-sdk');
var dbClient = new AWS.DynamoDB.DocumentClient();
AWS.config.update({
    region: "'us-east-1'"
});

let GetMachineStateIntent = (context, callback, dateSlot, timeSlot) => {    
  var params = {
    TableName: "updatedincident",
    KeyConditionExpression: 'date = :dVal and time < :tVal',
    ExpressionAttributeValues: {
       ':dVal': dateSlot,
       ':tVal': timeSlot
    },
    ScanIndexForward: false // gets values in reverse order by time 
  };
  dbClient.query(params, function (err, data) {
    if (err) {
       // failed to read from table for some reason..
       console.log('failed to load data item:\n' + JSON.stringify(err, null, 2));
       // let skill tell the user that it couldn't find the data 
       sendResponse(context, callback, {
          output: "the data could not be loaded from your database",
          endSession: false
       });
    } else {
       let dataItem = data.Items[0];           
       console.log('loaded data item:\n' + JSON.stringify(dataItem, null, 2));
       // assuming the item has an attribute called "state"..
       sendResponse(context, callback, {
          output: dataItem.state,
          endSession: false
       });
    }
  });
};


function sendResponse(context, callback, responseOptions) {
  if(typeof callback === 'undefined') {
    context.succeed(buildResponse(responseOptions));
  } else {
    callback(null, buildResponse(responseOptions));
  }
}

function buildResponse(options) {
  var alexaResponse = {
    version: "1.0",
    response: {
      outputSpeech: {
        "type": "SSML",
        "ssml": `<speak><prosody rate="slow">${options.output}</prosody></speak>`
      },
      shouldEndSession: options.endSession
    }
  };
  if (options.repromptText) {
    alexaResponse.response.reprompt = {
      outputSpeech: {
        "type": "SSML",
        "ssml": `<speak><prosody rate="slow">${options.reprompt}</prosody></speak>`
      }
    };
  }
  return alexaResponse;
}

exports.handler = (event, context, callback) => {
  try {
    var request = event.request;
    if (request.type === "LaunchRequest") {
      sendResponse(context, callback, {
        output: "welcome to my skill, I can tell you about the status of machines at different times. what data are you looking for?",
        endSession: false
      });
    } else if (request.type === "IntentRequest") {
      if (request.intent.name === "GetMachineStateIntent") {
        var dateSlot = request.intent.slots.Date != null 
             ? request.intent.slots.Date. value : null;
        var timeSlot = request.intent.slots.Time != null
             ? request.intent.slots.Time.value : null;
        // pass the slot values to the GetMachineStateIntent function
        GetMachineStateIntent(context, callback, dateSlot, timeSlot);
      } else if (request.intent.name === "AMAZON.StopIntent" || request.intent.name === "AMAZON.CancelIntent") {
        sendResponse(context, callback, {
          output: "ok. good bye!",
          endSession: true
        });
      }
      else if (request.intent.name === "AMAZON.HelpIntent") {
        sendResponse(context, callback, {
          output: "you can ask me about incidents that have happened or states of machines in the past",
          reprompt: "what can I help you with?",
          endSession: false
        });
      }
      else {
        sendResponse(context, callback, {
          output: "I don't know that one! please try again!",
          endSession: false
        });
      }
    }
    else if (request.type === "SessionEndedRequest") {
      sendResponse(context, callback, ""); // no response needed
    }
    else {
      // an unexpected request type received.. just say I don't know..
      sendResponse(context, callback, {
          output: "I don't know that one! please try again!",
          endSession: false
      });
    }
  } catch (e) {
    // handle the error by logging it and sending back an failure
    console.log('Unexpected error occurred in the skill handler!', e);
    if(typeof callback === 'undefined') {
       context.fail("Unexpected error");
    } else {
       callback("Unexpected error");
    }
  }
};

我目前使用上述代码得到的响应是

'the data could not be loaded from your database'

云表也告诉我这个

2018-05-16T09:29:06.635Z 93d4b6e6-58eb-11e8-b686-597d65771e90 failed to load data item:
{
    "message": "Invalid KeyConditionExpression: Attribute name is a reserved keyword; reserved keyword: date",
    "code": "ValidationException",
    "time": "2018-05-16T09:29:06.633Z",
    "requestId": "EQPQTAGO4QKH9SM5GSOA9O3DDFVV4KQNSO5AEMVJF66Q9ASUAAJG",
    "statusCode": 400,
    "retryable": false,
    "retryDelay": 35.56027710686527
}

Answer 1

在 GetMachineStateIntent 函数中，尝试像这样更改 params 结构：

var params = {
  TableName: "updatedincident",
  KeyConditionExpression: '#d = :dVal and #t < :tVal',
  ExpressionAttributeValues: {
     ':dVal': dateSlot,
     ':tVal': timeSlot
  },
  ExpressionAttributeNames: {
     '#d': 'date',
     '#t': 'time'
  },
  ScanIndexForward: false // gets values in reverse order by time 
};

看起来 date 这个词是保留关键字，所以它不能直接用在 date = :dVal 这样的表达式中，这就是为什么你必须给它一个属性名别名 (#d) 映射回实际的属性名称 (date).

Answer 2

在 DynamoDB 中，您必须使用两个键，即主键和主排序键。查询根据这两个键搜索请求的值。

试试我的代码：

'FindName': function() {

    var tableName = "CVRaman";
    var userName = "Prateek";
    var userId = "kapoor";

    const dynamodbParams = {
        TableName: tableName,
        Key: {
            userId: userId,
            userName: userName,
        },
        ProjectionExpression: 'userName', //Projection Expression is used to select only specific columns which we want to get
    };

    console.log("Attempting to find name", dynamodbParams);
    dynamoDb.get(dynamodbParams).promise()
        .then(data => {
            console.log('name found', dynamodbParams);
            console.log(data.Item.userName);
            var a = data.Item.userName;
            console.log(a);
            this.emit(':ask', 'Name as ' + a);

        })
        .catch(err => {
            console.log(err);
            this.emit(':tell', 'we have a problem');
        });
},

Dynamodb alexa 查询不调用数据项

Dynamodb alexa query not calling data item

node.js

amazon-web-services

amazon-dynamodb

alexa

alexa-skill