Preface

I wanted to build a Discord bot with TypeScript that had:

• A database
• A dashboard/website/domain
• An API for interactions & authentication with Discord

I previously created this same "hbd" bot that ran on nodejs runtime, built with the discord.js library.

client.login(process.env.BOT_TOKEN!).then(() => client.emit("time"));

While, the discord.js library offers a lot of essential utilities for interacting with discord, it doesn't quite fit for a bot that's going to be running through Nextjs/Vercel.

I wanted the bot to respond to interactions through edge runtime rather than running in an environment 24/7 waiting for interactions.

Now, bare with me... I am merely learning everything as I go along. 🤖

• Getting started
  • Interactions endpoint
• OAuth2
• Vercel postgres
• Prisma
• OAuth2 (continued)
  • Access token
  • Refresh token
• Encryption
• Cookies / JWT
• What's next?
• Final product

Getting started

• Copy all the Discord bot values (token, application ID, oauth token, public key, etc.) place them your environment variables locally and on Vercel.
• Clone the template repository
  • Either the initial one: jzxhuang/nextjs-discord-bot
  • Or the one I built that already has oauth2 (but I will discuss both): clxrityy/nextjs-discord-bot-with-oauth

Alright, as much as I'd like to take credit for the whole "discord bot with nextjs" implementation, my starting point was finding this extremely useful repository that had already put an interactions endpoint & command registration script into place.

jzxhuang/nextjs-discord-bot

Interactions endpoint

• Set your discord bot's interactions endpoint url to https://<VERCEL_URL>/api/interactions.

/api/interactions

• Set the the runtime to edge: ```ts

export const runtime = "edge";

- The interaction is [**verified**](https://discord.com/developers/docs/interactions/receiving-and-responding#receiving-an-interaction) to be [received & responded](https://discord.com/developers/docs/interactions/receiving-and-responding#security-and-authorization) to within the route using some [logic](https://github.com/clxrityy/nextjs-discord-bot-with-oauth/blob/main/src/discord/verify-incoming-request.ts) implemented by the template creator that I haven't bothered to understand.
- The interaction data is parsed into a custom type so that it can be interacted with regardless of it's sub-command(s)/option(s) structure:
```ts


export interface InteractionData {
    id: string;
    name: string;
    options?: InteractionSubcommand<InteractionOption>[] | InteractionOption[] | InteractionSubcommandGroup<InteractionSubcommand<InteractionOption>>[];
}

The last bit of the interactions endpoint structure (that I'm not entirely proud of) is that I'm using switch cases between every command name within the route to execute an external function/handler that generates the response for that specific command. But, this could be more efficient/easier-to-read in the future

import { commands } from "@/data/commands";

const { name } = interaction.data;
// ...
switch (name) {
    case commands.ping.name:

        embed = {
             title: "Pong!",
             color: Colors.BLURPLE
        }

        return NextResponse.json({
               type: InteractionResponseType.ChannelMessageWithSource,
               data: {
                    embeds: [JSON.parse(JSON.stringify(embed))]
               }
        });
// ...
}

OAuth2

Authentication endpoint

That template had everything necessary to lift this project off the ground, use interactions, and display UI elements based on the bot's data.
However, I wanted to create another template I could use that implemented authentication with Discord so that there can be an interactive dashboard.

I will go over the whole process, but you can see in-depth everything I changed about the initial template in this pull request:

With oauth2 #4

clxrityy posted on Jun 10, 2024

nextjs-discord-bot (with oauth2)

• Production URL: https://nextjs-discord-bot-with-oauth.vercel.app/

Overview

Accessing the designated root url (/) will require authentication with Discord. Upon authorizing, the user will be redirected back to the root url (with additional user details displayed)

ex.

---

Replication

OAuth2 URLs

• Generate your own OAuth2 redirect URI with every additional scope needed (discord.com/applications/CLIENT_ID/oauth2)

  • The path should be /api/auth/discord/redirect

    

• Add these urls (development and production) to config.ts:

  export const CONFIG = {
    REDIRECT_URI:
      process.env.NODE_ENV === "development"
        ? "http://localhost:3000/api/auth/discord/redirect"
        : "https://yourdomain.com/api/auth/discord/redirect", // REPLACE WITH YOUR DOMAIN
    OAUTH2_INVITE_URL: process.env.NODE_ENV === "development" ? "" : "", // (copy the generated url)
    ROOT_URL: process.env.NODE_ENV === "development" ? "http://localhost:3000" : "", // REPLACE WITH YOUR DOMAIN
  }

Discord endpoints

• After making a POST request to Discord's oauth token endpoint (discord.com/api/v10/oauth2/token)
  • The access_token from the data given is used to receive the Discord user's details by making a GET request to the discord.com/api/v10users/@me endpoint:

    export async function getUserDetails(accessToken: string) {
      return await axios.get<OAuth2UserResponse>(CONFIG.OAUTH2_USER, {
        headers: {
          Authorization: `Bearer ${accessToken}`,
        },
      })
    }

---

Vercel Postgres / Prisma

I've implemented a prisma table which will store the encrypted access & refresh token from the user data. This can be used later, but for now has minimal impact on the application.

Getting Started with Vercel Postgres

Prisma is used to store the User model:

model User {
  id           String @id @default(uuid())
  userId       String @unique
  accessToken  String @unique
  refreshToken String @unique
}

Quickstart

Create a postgres database on your vercel dashboard

• This will automatically generate the necessary environment variables for the database.

Retreive the environment variables locally:

vercel env pull .env.development.local

Generate the prisma client:

npx prisma generate

Create the table(s) in your database based on your prisma schema:

npx prisma db push

• The build script within package.json has been altered to support the prisma database in production:

  "build": "prisma generate && next build"

---

Encryption

crypto-js is used to encrypt the access_token & refresh_token before storing into the User model.

import CryptoJS from 'crypto-js';

export const encryptToken = (token: string) => CryptoJS.AES.encrypt(token, process.env.ENCRYPTION_KEY);

• Add a custom ENCRYPTION_KEY environment variable (make sure to also add this to your vercel project environment variables)

Cookies & JWT

jsonwebtoken & cookie are used for signing & serializing the cookie for the user session.

• Add a custom JWT_SECRET environment variable (make sure to also add this to your vercel project environment variables)

import { CONFIG } from "@/config";
import { serialize } from "cookie";
import { sign } from "jsonwebtoken";
import { cookies } from "next/headers";

const token = sign(user.data, process.env.JWT_SECRET, {
    expiresIn: "24h"
});

cookies().set(CONFIG.cookieName, serialize(CONFIG.cookieName, token, {
    httpOnly: true,
    secure: process.env.NODE_ENV === "production",
    sameSite: "lax",
    path: "/"
}))

---

Updates

• The .env.local.example has been updated to include:

# discord.com/developers/applications/APP_ID/oauth2
DISCORD_CLIENT_SECRET=

# Encryption: a custom secret key for encrypting sensitive data
# This is used to encrypt the user's Discord token in the database
# If you don't set this, the app will use a default key
ENCRYPTION_KEY=

# JWT for cookies
# This is used to sign the JWT token for the user's session
# If you don't set this, the app will use a default key
JWT_SECRET=

# Prisma / Postgres
# These are used to connect to the database
# See here: https://vercel.com/docs/storage/vercel-postgres/quickstart
POSTGRES_DATABASE=
POSTGRES_HOST=
POSTGRES_PASSWORD=
POSTGRES_PRISMA_URL=
POSTGRES_URL=
POSTGRES_URL_NON_POOLING=
POSTGRES_URL_NO_SSL=

• An additional config.ts has been made to include necesssary authentication URLs

View on GitHub

/api/auth/discord/redirect

• Add your redirect URI to your Discord application: (should be found at https://discord.com/developers/applications/{APP_ID}/oauth2)
  • Development - http://localhost:3000/api/auth/discord/redirect
  • Production - https://VERCEL_URL/api/auth/discord/redirect

I know off the bat I'm gonna need to start implementing the database aspect of this application now; as I need a way to store user data (such as refresh tokens, user id, etc.)

... Let's take a brief intermission and talk about Prisma & Vercel Postgres

Vercel has this amazing feature, you can create a postgresql database directly through Vercel and connect it to any project(s) you want.

I'm not sponsored but I should be

Vercel Postgres

• pnpm add @vercel/postgres
• Install Vercel CLI
  • pnpm i -g vercel@latest
• Create a postgres database
• Get those environment variables loaded locally
  • vercel env pull .env.development.local

Prisma

• Install prisma
  • pnpm add -D prisma
  • pnpm add @prisma/client

• Since I'm going to be using prisma on the edge as well, I'm going to install Prisma Accelerate

  • pnpm add @prisma/extension-accelerate

• Initialize the prisma client

  • npx prisma init

You should now have prisma/schema.prisma in your root directory:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider  = "postgresql"
  url       = env("POSTGRES_URL")
  directUrl = env("POSTGRES_URL_NON_POOLING")
}

Make sure url & directUrl are set to your environment variable values

• Get your accelerate URL: console.prisma.io

src/lib/db.ts

import { PrismaClient } from "@prisma/client/edge";
import { withAccelerate } from '@prisma/extension-accelerate';

function makePrisma() {
    return new PrismaClient({
        datasources: {
            db: {
                url: process.env.ACCELERATE_URL!,
            }
        }
    }).$extends(withAccelerate());
}

const globalForPrisma = global as unknown as {
    prisma: ReturnType<typeof makePrisma>;
}

export const db = globalForPrisma.prisma ?? makePrisma();

if (process.env.NODE_ENV !== "production") {
    globalForPrisma.prisma = makePrisma();
}

Don't ask me why it's set up this way, or why this is the best way... just trust~

• Lastly, update your package.json to generate the prisma client upon build.
  • Adding --no-engine is recommended when using prisma accelerate. ```json

scripts: {
"build": "npx prisma generate --no-engine && next build",
},

---

### Back to OAuth2 

- Create your route (mine is `api/auth/discord/redirect/route.ts`)

This route is automatically going to give a `code` url parameter upon successful authentication with Discord (make sure the route is set as the REDIRECT_URI in your bot settings).

```ts


export async function GET(req: Request) {
    const urlParams = new URL(req.url).searchParams;

    const code = urlParams.get("code");
}

You need this code to generate an access token and a refresh token.

Access token

Consider the access token as an item (such as a token) that authorizes the client (authorized website user) to interact with the API server (being Discord in this instance) on behalf of that same user.

Refresh token

Access tokens can only be available for so long (for security purposes), and the refresh token allows users to literally refresh their access token without doing the entire log in process again.

• Set up a query string that says "hey, here's the code, can I have the access and refresh tokens"

const scope = ["identify"].join(" ");

const OAUTH_QS = new URLSearchParams({
    client_id: process.env.CLIENT_ID!,
    redirect_uri: CONFIG.URLS.REDIRECT_URI,
    response_type: "code",
    scope
}).toString();

const OAUTH_URL = `https://discord.com/api/oauth2/authorize?${OAUTH_QS}`;

• Build the OAuth2 request payload (the body of the upcoming request)

export type OAuthTokenExchangeRequestParams = {
    client_id: string;
    client_secret: string;
    grant_type: string;
    code: string;
    redirect_uri: string;
    scope: string;
}

const buildOAuth2RequestPayload = (data: OAuthTokenExchangeRequestParams) => new URLSearchParams(data).toString();

const body = buildOAuth2RequestPayload({
    client_id: process.env.CLIENT_ID!,
    client_secret: process.env.CLIENT_SECRET!,
    grant_type: "authorization_code",
    code,
    redirect_uri: CONFIG.URLS.REDIRECT_URI,
    scope
}).toString();

• Now we should be able to access the access_token and refresh_token by deconstructing the data from the POST request to the OAUTH_URL.

const { data } = await axios.post<OAuth2CrendialsResponse>(CONFIG.URLS.OAUTH2_TOKEN, body, {
    headers: {
        "Content-Type": "application/x-www-form-urlencoded",
    }
});
const { access_token, refresh_token } = data;

I'm gonna wanna store these as encrypted values, along with some other user data, in a User model, and set up functions to update those values.

model User {
  id           String     @id @default(uuid())
  userId       String     @unique
  accessToken  String     @unique
  refreshToken String     @unique
}

• Get the user details using the access token

export async function getUserDetails(accessToken: string) {
    return await axios.get<OAuth2UserResponse>(`https://discord.com/api/v10/users/@me`, {
        headers: {
            Authorization: `Bearer ${accessToken}`
        }
    })
};

Encryption

In order to store the access_token & refresh_token, it's good practice to encrypt those values.

I'm using crypto-js.

• Add an ENCRYPTION_KEY environment variable locally and on Vercel.

import CryptoJS from 'crypto-js';

export const encryptToken = (token: string) => CryptoJS.AES.encrypt(token, process.env.ENCRYPTION_KEY!);
export const decryptToken = (encrypted: string) => CryptoJS.AES.decrypt(encrypted, process.env.ENCRYPTION_KEY!).toString(CryptoJS.enc.Utf8);

• Now you can store those values in the User model

import { db } from "@/lib/db";

await db.user.create({
    data: {
        userId,
        accessToken, // encrypted
        refreshToken, // encrypted
    }
});

Cookies / JWT

• Add a JWT_SECRET environment variable locally & on Vercel.

Cookies are bits of data the website sends to the client to recount information about the user's visit.

I'm going to be using jsonwebtoken, cookie, & the cookies() (from next/headers) to manage cookies.

Within this route (if the code exists, there's no error, and user data exists) I'm going to set a cookie, as users should only be directed to this route upon authentication.

• Sign the token ```ts

import { sign } from "jsonwebtoken";

const token = sign(user.data, process.env.JWT_SECRET!, { expiresIn: "72h" });

- Set the cookie
  - You can name this cookie whatever you want.
```ts


import { cookies } from "next/headers";
import { serialize } from "cookie";

cookies().set("cookie_name", serialize("cookie_name", token, {
    httpOnly: true,
    secure: process.env.NODE_ENV === "production", // secure when in production
    sameSite: "lax",
    path: "/"
}));

Then you can redirect the user to the application!

import { NextResponse } from 'next/server';
//...
return NextResponse.redirect(BASE_URL);

View the full route code

Check for a cookie to ensure a user is authenticated:

import { parse } from "cookie";
import { verify } from "jsonwebtoken";
import { cookies } from "next/headers";

export function parseUser(): OAuth2UserResponse | null {

    const cookie = cookies().get(CONFIG.VALUES.COOKIE_NAME);
    if (!cookie?.value) {
        return null;
    }

    const token = parse(cookie.value)[CONFIG.VALUES.COOKIE_NAME];
    if (!token) {
        return null;
    }
    try {
        const { iat, exp, ...user } = verify(token, process.env.JWT_SECRET) as OAuth2UserResponse & { iat: number, exp: number };

        return user;
    } catch (e) {
        console.log(`Error parsing user: ${e}`);
        return null;
    }
}

What's next?

With this, you have a fully authenticated Discord application with Nextjs!

Utilizing discord & user data, you can add on by...

• Add pages for guilds / user profiles
• Give guild admins the ability to alter specific guild configurations for the bot through the dashboard
• Display data about commands
  • Example commands page
• Add premium features
  • Integrate stripe for paid features only available to premium users
• Leaderboards / statistics
  • Guild with the most members, user who's used the most commands, etc...

The possibilities are endless, and your starting point to making something amazing is right here.

Final product

You can clone the template repository here.

• My bot (hbd) is hosted here: hbd.mjanglin.com
• 🔗 Invite
• Support server
• GitHub repo
• Source structure overview

Thanks for reading! Give this post a ❤️ if you found it helpful!
I'm open to comments/suggestions/ideas!