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Overview

Let’s set up a script that sends one of Paul Graham’s top essays to our inbox every Monday, Wednesday, and Friday.

Here’s how we’ll tackle it:

  1. Write the script to fetch a random essay from Paul Graham’s most popular essays
  2. Set up an email to be sent with the essay every Monday/Wednesday/Friday
  3. Configure the schedule so that it “remembers” which essays have already been sent through

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Fetching essay data

We’ll use the cheerio library to parse the essay page HTML. Here’s what that function might look like:

Here’s what the output of that might look like:

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Triggering an email with the essay

First, let’s define a helper function to pick a random essay:

Now, all we have to do is trigger the email.

Here we handle that in a NextJS API endpoint:

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Keeping track of alert history

When you create a job on a schedule, the scheduler will pass in some metadata into the body of each request. Included in the metadata is the schedule’s state, which can be accessed at req.body.$state and set or updated in the response.

Let’s modify the API handler to take advantage of $state:

export default async function handler(req, res) {
  // ...

  const exclude = req.body.$state?.sent || [];
  const essay = req.body.essay || getRandomEssay(exclude);

  // ...

  const email = await resend.sendEmail({...});

  return res.json({ email, $set: { sent: [...exclude, essay] } });
}

We can clean this up a bit by taking advantage of dynamic values in our job schedule configuration. When we set the request body for our job, we can write it like this:

{
  // Pass in `req.body.$state?.sent` as `req.body.exclude`
  "exclude": "$state.sent"
}

If we do this, we can change the line above from this:

const exclude = req.body.$state?.sent || [];

To this:

const exclude = req.body.exclude || [];

Now, assuming you’ve deployed your API endpoint to https://yourdomain.com/api/pg, you can create your scheduled job by running the following script in your terminal with your BOOPER_API_KEY set, and the url modified to the appropriate domain:

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