Searching DynamoDB for non primary keys and integrating into Alexa Skills - amazon-web-services

Question

I am trying to search a non primary key using AWS Lambda and integrating it into the Alexa Skills Kit. I am very new to using DynamoDB and Alexa Skills Kit and I'm struggling to find any solutions to this online. The basic premise for what I am trying to do is querying the table yesno with two columns, id and message. Only looking through the message column to find a match with the text i specify in params.
Here is the Lambda code I am working with:
const AWSregion = 'eu-west-1';
const Alexa = require('alexa-sdk');
const AWS = require('aws-sdk');
//params for searching table
const params = {
TableName: 'yesno',
Key:{ "message": 'Ben Davies' }
};
AWS.config.update({
region: AWSregion
});
exports.handler = function(event, context, callback) {
var alexa = Alexa.handler(event, context);
// alexa.appId = 'amzn1.echo-sdk-ams.app.1234';
// alexa.dynamoDBTableName = 'YourTableName'; // creates new table for session.attributes
alexa.registerHandlers(handlers);
alexa.execute();
};
const handlers = {
'LaunchRequest': function () {
this.response.speak('welcome to magic answers. ask me a yes or no question.').listen('try again');
this.emit(':responseReady');
},
'MyIntent': function () {
var MyQuestion = this.event.request.intent.slots.MyQuestion.value;
console.log('MyQuestion : ' + MyQuestion);
readDynamoItem(params, myResult=>{
var say = MyQuestion;
say = myResult;
say = 'you asked, ' + MyQuestion + '. I found a reckord for: ' + myResult;
this.response.speak(say).listen('try again');
this.emit(':responseReady');
});
},
'AMAZON.HelpIntent': function () {
this.response.speak('ask me a yes or no question.').listen('try again');
this.emit(':responseReady');
},
'AMAZON.CancelIntent': function () {
this.response.speak('Goodbye!');
this.emit(':responseReady');
},
'AMAZON.StopIntent': function () {
this.response.speak('Goodbye!');
this.emit(':responseReady');
}
};
// END of Intent Handlers {} ========================================================================================
// Helper Function =================================================================================================
function readDynamoItem(params, callback) {
var AWS = require('aws-sdk');
AWS.config.update({region: AWSregion});
var dynamodb = new AWS.DynamoDB();
console.log('reading item from DynamoDB table');
dynamodb.query(params, function (err, data) {
if (err) console.log(err, err.stack); // an error occurred
else{
console.log(data); // successful response
callback(data.Item.message);
}
});
}
I know I am probably doing this completely wrong but there isn't much online for integrating DynamoDB with an Alexa Skill and the only thing i was able to find was searching by ID. This doesn't work for what i want to do without pulling all the items from the table into a map or a list, and seeing as I want to create a big database it seems quite inefficient.
On the Alexa side of things I am receiving the following service request when testing the code:
{
"session": {
"new": true,
"sessionId": "SessionId.f9558462-6db8-4bf5-84aa-22ee0920ae95",
"application": {
"applicationId": "amzn1.ask.skill.9f280bf7-d506-4d58-95e8-b9e93a66a420"
},
"attributes": {},
"user": {
"userId": "amzn1.ask.account.AF5IJBMLKNE32GEFQ5VFGVK2P4YQOLVUSA5YPY7RNEMDPKSVCBRCPWC3OBHXEXAHROBTT7FGIYA7HJW2PMEGXWHF6SQHRX3VA372OHPZZJ33K7S4K7D6V3PXYB6I72YFIQBHMJ4QGJW3NS3E2ZFY5YFSBOEFW6V2E75YAZMRQCU7MNYPJUMJSUISSUA2WF2RA3CIIDCSEY35TWI"
}
},
"request": {
"type": "IntentRequest",
"requestId": "EdwRequestId.7310073b-981a-41f8-9fa5-03d1b28c5aba",
"intent": {
"name": "MyIntent",
"slots": {
"MyQuestion": {
"name": "MyQuestion",
"value": "erere"
}
}
},
"locale": "en-US",
"timestamp": "2018-01-25T14:18:40Z"
},
"context": {
"AudioPlayer": {
"playerActivity": "IDLE"
},
"System": {
"application": {
"applicationId": "amzn1.ask.skill.9f280bf7-d506-4d58-95e8-b9e93a66a420"
},
"user": {
"userId": "amzn1.ask.account.AF5IJBMLKNE32GEFQ5VFGVK2P4YQOLVUSA5YPY7RNEMDPKSVCBRCPWC3OBHXEXAHROBTT7FGIYA7HJW2PMEGXWHF6SQHRX3VA372OHPZZJ33K7S4K7D6V3PXYB6I72YFIQBHMJ4QGJW3NS3E2ZFY5YFSBOEFW6V2E75YAZMRQCU7MNYPJUMJSUISSUA2WF2RA3CIIDCSEY35TWI"
},
"device": {
"supportedInterfaces": {}
}
}
},
"version": "1.0"
}
And I am receiving a service response error simply saying 'The response is invalid'
Any help with this would be greatly appreciated

Answer 1

I would like to help you in dynamo db part.
In order to access non primary key columns in dynamodb you should perform scan operation.
For your table (yesno), id is a primary key and message is an additional column.
Snippet to access non primary key column [Message]
var dynamodb = new AWS.DynamoDB();
var params = {
TableName: 'yesno',
FilterExpression: 'message = :value',
ExpressionAttributeValues: {
':value': {"S": "Ben Davies"}
}
};
dynamodb.scan(params, function(err, data) {
if (err) // an error occurred
else console.log(data); // successful response
});
Snippet to access primary key column [Id]
var docClient = new AWS.DynamoDB.DocumentClient();
//Get item by key
var params = {
TableName: 'sis_org_template',
Key: { "id": "1"}
};
docClient.get(params, function(err, data) {
if (err) // an error occurred
else console.log(data); // successful response
});