Bytesized

Bytesized • Resources, tutorials, and newsletters for software developers.

How to build a Discord notification bot for new Ghost members

In this blog post, we'll use Cloudflare Workers to deploy a serverless function for posting new subscriber notifications from Ghost to a Discord channel.

How to build a Discord notification bot for new Ghost members

This blog is powered by Ghost, a great open-source blogging platform. Recently, I moved the Bytesized newsletter (subscribe by clicking this link!) to using Ghost's built-in membership feature.

To know when someone new has subscribed to the site, I wanted to set up a notification bot in the Bytesized Discord server (in a private channel). Discord bots are pretty lightweight, and as long as you can make an HTTP POST request, it's a really simple way to build out notifications for your service (think Slack a few years ago, but free!).

Example Discord notifications using channel webhooks

Here's how I built my Ghost to Discord notification bot, using Cloudflare Workers as a webhook platform!

Setting up the Discord bot

Discord bots are essentially unique and authenticated URLs, with the information already preset to post to a specific channel. For my use-case, I created a new channel #newsletter-subs and made it available to just the Moderator role (so only I can read it).

Once you've created a new Discord channel (or picked the existing one you want to use), go to the channel settings by clicking the "Edit Channel" button on Discord's sidebar (the gear icon when you highlight over a channel). In the channel settings, select the "Integrations" page, and then the "View webhooks" button.

The integrations and webhooks UI in Discord's channel settings

You can create a new webhook by clicking the "New Webhook" button. This will give you a few options – first, the display settings for the webhook: the image and name that messages will post as, and the channel you want to post to.

When you're ready to use the webhook, select the "Copy Webhook URL" button, and a unique webhook URL will be saved to your clipboard. This should be kept secret! This URL is authenticated as your webhook and will allow anyone with access to it to post directly into your channel.

Setting up the Ghost webhook

Now we'll set up the Ghost webhook that will send data from your Ghost instance. Every time a new member joins your site, a special JSON payload with info about the member will be sent to a URL of your choice.

Webhooks in Ghost are part of integrations. To create an integration, navigate to the "Integrations" tab in your Ghost admin sidebar, and then select the (quite small) "Add custom integration" button.

Ghost's integrations page

Give your integration a name, and then in your new integration page, select "Add webhook". Call your webhook something like "New member', and then for the Event (the thing happening in your Ghost blog that this webhook should fire after), select "Member added".

You might think that your Target URL – where Ghost sends the data to – would be your Discord webhook URL. Instead of using that value, we'll deploy a serverless function using Cloudflare Workers. This function will take the data from Ghost, and format it into a Discord message fit for posting to your channel.

For now, you can put in a random URL of your choice, and once we've published our serverless function, we'll come back and fill in the right value.

Deploying a Cloudflare Workers function to translate Ghost data for Discord

Cloudflare Workers is a serverless platform built on Cloudflare's global network that makes it super easy to deploy and manage JavaScript functions. (Disclaimer: I work as the developer advocate for Workers!)

Workers is a great platform for this kind of translation work – taking JSON in, transforming it, and sending JSON out to somewhere else.

If you aren't familiar with Cloudflare Workers, it's worthwhile to spend 20-30 minutes diving through my Egghead.io course. I'll teach you how to set up your Cloudflare account, sign up for Workers, and deploy your first project with Wrangler, our command-line tool. Watch it for free below!

Introduction to Cloudflare Workers

Instead of making you write the code from scratch, I've set up an open-source project that transforms Ghost's JSON into a format ready for Discord. You can find it at signalnerve/ghost-member-discord-notifications:

signalnerve/ghost-member-discord-notifications
Cloudflare Workers webhook bridge for posting new member notifications from Ghost in Discord - signalnerve/ghost-member-discord-notifications

Here's how to deploy it yourself:

  1. Make sure you have wrangler, the Workers command-line tool, installed and authenticated. If you didn't go through the Egghead course linked above, you can also follow our Quick Start guide to get wrangler up and running.
  2. Clone the project locally to your computer: git clone [email protected]:signalnerve/ghost-member-discord-notifications.git
  3. Update the account_id value in wrangler.toml – to find that value, you can use wrangler whoami, or follow the instructions for finding it in our Quick Start.
  4. Publish your instance of the project using wrangler publish – note that it will deploy in the format <project>.<subdomain>.workers.dev, where <project> is your project's name in wrangler.toml (defaulted to ghost-to-discord), and <subdomain> is the custom subdomain you selected when signing up for your Workers account.
  5. Once published, you need to set up a few secrets – values that your Workers function will use while executing – using wrangler secret. Your PASSWORD secret will be a string password that the Worker will use to validate that a request is coming from Ghost, and DISCORD_URL will be the webhook URL that we copied from Discord back in the first section of this guide. See the "Configuration" section of the open-source project to learn how to set these values!

Setting the Ghost webhook URL and testing

Once you've published your Workers project, you'll see the URL of your serverless function in Wrangler's output.

Once you have that URL available, we can use it to build the final URL that we'll pass to Ghost's webhook configuration. Note that the serverless function I've pushed onto GitHub uses the path /member_added (just in case I want to handle more webhook types in the future), and that you'll also need to pass the key query parameter to authenticate with the Workers function. That means that the final URL will look like this (see the screenshot below for a live example, too):

https://<project>.<subdomain>.workers.dev/member_added?key=<password>

Back in Ghost's integration page, you can select your existing webhook and fill in the correct URL for your Workers function.

A custom webhook created in Ghost's admin UI

Now, to test your new function, just go to your blog's homepage and sign up with a new test email. You can also make sure that it's working on my end by joining the Bytesized newsletter, too 😁

When a new member subscribes, you should see a new message posted in your Discord channel – neat!

An example message posted in a Discord channel using the codebase in this tutorial

Discord message configuration

There's a lot of configuration you can do with Discord notifications that are out of scope for this article – like Slack, you can do things like embeds – more dynamic information presented as an attachment to a message, or simple things like customizing the name or image for the message as they get sent to Discord's API.

I've exposed a few of these inside of the Workers function I've open-sourced. In index.js, the config object contains a function called createBody, which can be used to define a custom Discord message object based on the values coming from Ghost:

createBody: ({ id, uuid, email, name, note, geolocation, subscribed, created_at, updated_at, avatar_image, labels }) => 
  JSON.stringify({
    avatar_url: avatar_image,
    content: `${name} (${email}) just subscribed to Bytesized!`
  })

Discohook is a great interactive playground for testing your message content before sending it to Discord, including testing embeds, custom content and avatars, and more. Of course, Discord's API documentation is a good reference as well – if you want to customize the output of this serverless function to your use-case, check out Discord's execute-webhook endpoint documentation to learn more about the available options.

Enjoying these posts? Subscribe for more

Subscribe to be notified of new content and support Bytesized! You'll be a part of the community helping keep this site independent and ad-free.

You've successfully subscribed to Bytesized
Great! Next, complete checkout for full access to Bytesized
Welcome back! You've successfully signed in
Success! Your account is fully activated, you now have access to all content.