Serverless AWS Twilio Dictionary

A serverless dictionary hosted on AWS with Twilio account integration that enables SMS communication.

Usage

After installation, you can interact with the dictionary using the following syntax:

[command] word [definition]

There are four commands (see list below). If omitted, the command defaults to read. The word is the dictionary key and one must be provided with all dictionary interactions. The definition part is used when creating or updating the meaning of different words.

Command	Abbreviation	Comment
create	c	Creates a new entry in the dictionary
read	r	Reads an entry from dictionary (default command)
update	u	Updates a dictionary entry
delete	d	Deletes a dictionary entry

Examples:

create TLA Three Letter Acronym

Adds the entry TLA with the definition Three Letter Acronym to the dictionary

r TLA

or just

TLA

reads the value of the TLA entry

Architecture

The phone sends an SMS message to the Twilio platform which in turn performs a HTTP request to the serverless dictionary in the AWS cloud. The HTTP response from the serverless dictionary is then translated back to text by the Twilio platform before it sends it back to the phone as another SMS message. Consequently, the Twilio platform is responsible for phone the phone interaction and the AWS part is responsible for the providing HTTP communication, application logic and storage. Consequently, the AWS parrts consists of a HTTP API that forwards the request to a Lambda function, which in turns communicate with a DynamoDB table.

AWS Installation

Prerequisites

• An AWS account
• AWS CLI installed and configured
• Node.js version 12.x (see .nvmrc) if you are using nvm

Step by Step

1. Clone the project
2. Install the dependencies: $ npm install
3. Compile the AWS CDK TypeScript to JavaScript: npm run build
4. Synthesize and deploy the infrastructure to AWS CloudFormation: npx cdk deploy
5. Take note of the ServerlessDictionaryStack.PublicDomainName output value as this will be used later
6. Verify that the serverless dictionary was deployed successfully by executing the post.sh script, e.g.

   ./post.sh "create TLA Three Letter Acronym"

Twilio Integration

1. Go to the https://www.twilio.com and create an account
2. Get a Twilio Phone Number
3. In the phone number's configuration options, find the Messaging part
   1. Find the A Message Comes In section
   2. Change the value to Webhook
   3. Configure the value of ServerlessDictionaryStack.PublicDomainName as mentioned earlier as webhook URL. Hint, if you forgot to copy it, you can find it in the outputs of your CloudFormation stack in the AWS Console Please see details at Configure a Webhook URL.

AWS CDK

The project infrastructure is based on the AWS CDK. The cdk.json file tells the CDK Toolkit how to execute your app. For more information, execute the npx cdk help.

AWS CDK Commands

• npm run build compile typescript to js
• npm run watch watch for changes and compile
• npm run test perform the jest unit tests
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk synth emits the synthesized CloudFormation template