VotingAppUsingAWS-Services

Create a Dynamo DB table with candidate attribute. Create Lambda Function (NodeJS) Create a New Role Which is in files CastVote.js -> click on test Lamda Code -> CastVote.js

'use strict'; console.log('Loading function'); const doc = require('aws-sdk'); // const doc = require('dynamodb-doc'); const dynamo = new doc.DynamoDB.DocumentClient();

const castVote = (payload, callback) => {

if (typeof payload === "string"){
    payload = JSON.parse(payload);
}

var params = {
    Key: { 
        candidate: payload.vote
    },
    TableName: 'VoteTally',
        AttributeUpdates: {
            tally: {
                Action: 'ADD',
                Value: 1
            }
        }
};

console.log('Casting Vote:', JSON.stringify(params, null, 2));

dynamo.update(params, (err, data) => {
    if (err) console.log(err, err.stack); // an error occurred
    else     console.log(data);           // successful response
    
    callback(err, data);
});

}

exports.handler = (event, context, callback) => { console.log('Received event:', JSON.stringify(event, null, 2));

const done = (err, res) => callback(null, {
    statusCode: err ? '400' : '204',
    body: err ? err.message : JSON.stringify(res),
    headers: {
        'Content-Type': 'application/json',
    },
});

switch (event.httpMethod) {
    case 'POST':
        castVote(event.body, done);
        break;
    default:
        done(new Error(`Unsupported method "${event.httpMethod}"`));
}

};

Test->CastVote.js before moving forward

Copy the CastVote.json integrate with Dynamo DB(ADD Trigger) Api GateWay Create post method Add Lambda Function to it.
Add the above in content

{ "httpMethod": "POST", "body": { #foreach( $token in $input.path('$').split('&') ) #set( $keyVal = $token.split('=') ) #set( $keyValSize = $keyVal.size() ) #if( $keyValSize >= 1 ) #set( $key = $util.urlDecode($keyVal[0]) ) #if( $keyValSize >= 2 ) #set( $val = $util.urlDecode($keyVal[1]) ) #else #set( $val = '' ) #end "$key": "$val"#if($foreach.hasNext),#end #end #end } }

In Integration response Add 204 in default and remove 200.

Deploy API
Copy Invoke URL and add it in index.html

Add s3 files in bucket with default settings add bucket policy and enable static Website Hosting

Bucket Policy { "Version": "2012-10-17", "Statement": [ { "Sid": "PublicRead", "Effect": "Allow", "Principal": "", "Action": [ "s3:GetObject", "s3:GetObjectVersion" ], "Resource": "arn:aws:s3:::YourBucketName/" } ] } Go to S3 Bucket Properties -> static hosting ->Copy Url