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discord-bot-cdk-construct
npm i discord-bot-cdk-construct
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discord-bot-cdk-construct

A CDK Construct for creating a serverless Discord bot. All you need to do is supply your code to handle the commands!

by Gerald McAlister

0.3.3 (see all)License:MITTypeScript:Built-In
npm i discord-bot-cdk-construct
Readme

discord-bot-cdk-construct

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A CDK Construct for creating a serverless Discord bot. All you need to do is supply your code to handle the commands!

Architecture Overview

This is the architecture for how this project is laid out server-side. The tools used to create these diagrams are:

The bot has a fairly straightforward setup:

The architecture diagram for the project.

The biggest confusion likely stems from the use of two Lambda functions instead of one. This is to ensure that the initial request can respond within Discord's 3 second time limit and return a proper response to the user.

Sample Usage

The usage is split into two parts: The AWS CDK stack that will be used, and a "commands" script that actually handles responding. It's recommended that you are familiar with CDK first before diving into using this.

Handling Commands

For handling commands, you just need to provide a Lambda function for sending response to Discord's Web APIs. As an example of how this can be done:

import {Context, Callback} from 'aws-lambda';
import { IDiscordEventRequest, IDiscordResponseData, getDiscordSecrets, sendFollowupMessage } from 'discord-bot-cdk-construct';

export async function handler(event: IDiscordEventRequest, context: Context,
  callback: Callback): Promise<string> {

  const discordSecret = await getDiscordSecrets();
  const endpointInfo = {
    authToken: discordSecret?.authToken,
    applicationId: discordSecret?.applicationId
  };
  const response = {
    tts: false,
    content: 'Hello world!',
    embeds: [],
    allowedMentions: [],
  };
  if (event.jsonBody.token && await sendFollowupMessage(endpointInfo, event.jsonBody.token, response)) {
    console.log('Responded successfully!');
  } else {
    console.log('Failed to send response!');
  }
  return '200';
}

Using the Construct

To create a stack to make use of the above script, you can create a stack like so:

import {Duration, Stack} from 'aws-cdk-lib';
import {Runtime} from 'aws-cdk-lib/aws-lambda';
import {NodejsFunction} from 'aws-cdk-lib/aws-lambda-nodejs';
import {DiscordBotConstruct} from 'discord-bot-cdk-construct';
import {Construct} from 'constructs';
import * as path from 'path';

/**
 * Creates a sample Discord bot endpoint that can be used.
 */
export class SampleDiscordBotStack extends Stack {
  /**
   * The constructor for building the stack.
   * @param {Construct} scope The Construct scope to create the stack in.
   * @param {string} id The ID of the stack to use.
   */
  constructor(scope: Construct, id: string) {
    super(scope, id);

    // Create the Commands Lambda.
    const discordCommandsLambda = new NodejsFunction(this, 'discord-commands-lambda', {
      runtime: Runtime.NODEJS_14_X,
      entry: path.join(__dirname, '../functions/DiscordCommands.ts'),
      handler: 'handler',
      timeout: Duration.seconds(60),
    });

    const discordBot = new DiscordBotConstruct(this, 'discord-bot-endpoint', {
      commandsLambdaFunction: discordCommandsLambda,
    });
  }
}

This can of course then be used in your CDK application like so:

import { App } from 'aws-cdk-lib';
import { SampleDiscordBotStack } from './stacks/sample-discord-bot-stack';

const app = new App();
const startAPIStack = new SampleDiscordBotStack(app, 'SampleDiscordBotStack');

Full Demo Project

A full example project utilzing this construct can be found here. Specifically, the start-api-stack.ts file uses the construct, with DiscordCommands.ts being the commands file (like shown above).

Packaging with JSII

In order to package everything with JSII, ensure you have the following installed:

  • Python3
  • Open JDK
  • Maven

See JSII's Prerequisites Documentation for more information.

Useful commands

  • npm run build compile typescript to js
  • npm run watch watch for changes and compile
  • npm run test perform the jest unit tests
  • npm run lint perform a lint check across the code
  • npm run fix-lint fix any lint issues automatically where possible
  • npm run package package all of the bindings for distribution

Downloads/wk

176

GitHub Stars

10

LAST COMMIT

5mos ago

MAINTAINERS

1

CONTRIBUTORS

3

OPEN ISSUES

2

OPEN PRs

0
VersionTagPublished
0.3.3
latest
5mos ago
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