Substack subscription serverless function

1
import { NowRequest, NowResponse } from '@now/node';
2
import axios from 'axios';
3

4
/**
5
 * This pulls the subscription URL defined as an environment variable
6
 */
7
const { SUBSCRIPTION_URL: subscriptionURL } = process.env;
8

9
/**
10
 * Queries the substack API
11
 * Sends the email to the substack subscribe API for the publication specified in the url option
12
 * @param {string} url the URL of the publication
13
 * @param {string} email the email that needs to be added as a subscriber to the newsletter
14
 */
15
export const subscribe = async (url: string, email: string) => {
16
  try {
17
    const res = await axios.post(`${url}/api/v1/free`, {
18
      first_url: `${url}/subscribe`,
19
      first_referrer: '',
20
      current_url: `${url}/subscribe`,
21
      current_referrer: '',
22
      referral_code: '',
23
      source: 'subscribe_page',
24
      email,
25
    });
26
    console.log(`${res.status} subscribed ${email} to ${subscriptionURL}`);
27
  } catch (error) {
28
    throw new Error(error);
29
  }
30
};
31

32
/**
33
 * The handler of serverless function
34
 * @param {NowRequest} req
35
 * @param {NowResponse} res
36
 */
37
const handler = async (
38
  req: NowRequest,
39
  res: NowResponse
40
): Promise<NowResponse> => {
41
  const { email } = req.body;
42

43
  try {
44
    await subscribe(subscriptionURL, email);
45
  } catch (error) {
46
    return res.status(500).json({ error });
47
  }
48

49
  return res.status(200).json({ response: 'subscribed!' });
50
};
51

52
export default handler;