Hacker News Slack Bot

Built With

1. Vercel Functions for cron processes & event subscriptions via webhooks
2. Vercel Cron Jobs for triggering cron processes.
3. Hacker News API for pulling data
4. Slack API for sending and unfurling messages
5. Upstash for key-value storage (Redis).

How It Works

1. Set up a Vercel cron job that pings our /api/cron endpoint once every 60 seconds.
2. Get the last checked HN post ID (lastCheckedId) and the list of keywords to check against from Upstash.
3. Get the latestPostId using HN API's maxitem endpoint. Then, perform checks against each post between lastCheckedId and latestPostId to see if they contain any of the delineated keywords.
4. For each positive post, send its link to Slack using the chat.postMessage method.
5. Listen to the link_shared event at our /api/event endpoint. Once an event occurs, send a POST request to Slack to unfurl the link using the chat.unfurl method.

One-Click Install

Here's a 60s video that walks you through the installation process, step-by-step.

You can click the button below to install the bot directly into your desired Slack workspace:

Once it's installed, create a channel to receive notifications in and start configuring the bot with the /configure command.

Deploy Your Own

You can also deploy your own version of this bot using Vercel and Upstash. Note that while this is in early-access, some of these processes might change.

Prefer a video tutorial instead? Watch this video.

Step 1: Create Slack App + Secure Env Vars

1. Navigate to api.slack.com/apps and click on "Create New App".
2. Select "From scratch" and input Hacker News Bot as the name of your app.
3. Voilà! You've just created your Slack app. Here, you'll receive 3 values that will be used for your Vercel deployment in the next step:
   • Client ID: This is your App's unique public-facing ID that will be the value for the NEXT_PUBLIC_SLACK_CLIENT_ID env var.
   • Signing Secret: This is the signing secret used to validate that requests are genuinely coming from Slack. It will be the value for the SLACK_SIGNING_SECRET env var.
   • Verification Token: This is the verification token used to validate that requests are genuinely coming from Slack. It will be the value for the SLACK_VERIFICATION_TOKEN env var.

Step 2: Create Upstash Account

Go to console.upstash.com and create an account. You'll need it for the next step.

Step 3: Deploy to Vercel

You can deploy your bot to Vercel with one-click:

Be sure to include all 5 of the env vars above in your deployment.

When the project finishes deploying, get your project's domain (e.g. https://slacker-eight.vercel.app/). You'll need it for the next step.

Step 4: Configuring Slack app

For your Slack app to be able to send/unfurl messages in your Slack workspace, we will need to configure a few things:

Step 4A: Configuring OAuth Scopes

1. From your Slack app home screen, select "OAuth & Permissions" from the sidebar (under "Features").

2. Scroll down to "Scopes", and add the following scopes under "Bot Token Scopes":

   • chat:write
   • chat:write.public
   • links:read
   • links:write

Step 4B: Configuring Event Subscriptions

1. Now, select "Event Subscriptions" from the sidebar (under "Features").
2. Toggle "Enable Events" to "ON".
3. For the "Request URL" field, input your Vercel project's domain and append /api/event to it. The final URL should look something like https://slacker-eight.vercel.app/api/event.
4. Scroll down to "Subscribe to bot events". Add the link_shared bot user event.
5. Do the same for `Subscribe to events on behalf of users".
6. Under "App unfurl domains", add news.ycombinator.com.
7. Click on "Save Changes".

Step 4C: Configure Slash Commands

Select "Slash Commands" from the sidebar (under "Features"). Create the following commmand with its respective Request URLs (based on your Vercel project's domain):

• Command: /configure
• Request URL: https://[YOUR_VERCEL_PROJECT_DOMAIN]/api/cmd/configure
• Short Description: Configure your HN Slack Bot

Step 4D: Enable Interactivity

1. Now, select "Interactivity & Shortcuts" from the sidebar (under "Features").
2. Toggle "Interactivity" to "ON".
3. For the "Request URL" field, input your Vercel project's domain and append /api/response to it. The final URL should look something like https://slacker-eight.vercel.app/api/response.
4. Click on "Save Changes".

Step 4E: Install App to Slack Workspace + Get OAuth token

1. Go to "Basic Information" (under "Settings").
2. Under "Install your app", click on "Install to Workspace".
3. You should receive a notification that your app has been installed in your Slack workspace.
4. Go back to "OAuth & Permissions". Copy the value of "Bot User OAuth Token".
5. Set it as the SLACK_OAUTH_TOKEN env var in your Vercel project. Here's a guide on how to do that.
6. Redeploy your Vercel project for the changes to take effect.
7. To verify that this worked, go to any channel on your Slack workspace and send a Hacker News link. The link should now unfurl and show a nice preview (like the one above).

Authors

This project was originally created by Steven Tey at Vercel, with contributions/feedback from:

• Guillermo Rauch (@rauchg) – Vercel
• Justin Ridgewell (@jridgewell) – Vercel
• Andrew Healey (@healeycodes) – Vercel
• Drew Bredvick (@dbredvick) – Vercel
• Lee Robinson (@leeerob) – Vercel
• Andreas Thomas (@chronarkdotdev) – Upstash

License

The MIT License.