Add Subscriber to Revue (https://getrevue.co) using Serverless (AWS Lambda)

addSubscriberToRevue.js

'use strict';

  /*
    Before creating your service,
    add your API key to serverless.yml file
    For example, a valid conf:
    
    service:
      name: revue
    provider:
      name: aws
      runtime: nodejs6.10
      profile: default
      environment:
        api_key: XXX_YOUR_API_KEY
    functions:
      addSubscriber:
        handler: addSubscriber.handler
        events:
          - http: POST addSubscriber
        cors: true    
 */

const request = require('request');

const url = 'https://www.getrevue.co/api/v2/subscribers';

module.exports.handler = (event, context, callback) => {
  const email = event.email;

  if (!process.env.api_key) {
    return callback(null, {
      statusCode: 400,
      body: JSON.stringify({
        message: `Please provide your Revue API key (https://www.getrevue.co/app/integrations)`,
        errorType: 'NO_API_KEY_PROVIDED',
      }),
    });
  }
  if (!email) {
    return callback(null, {
      statusCode: 400,
      body: JSON.stringify({
        message: `Please provide us with a valid email!`,
        errorType: 'NO_EMAIL_PROVIDED',
      }),
    });
  }
  return request.post({
    url,
    headers: {
      Authorization: `Token token="${process.env.api_key}"`,
    },
    formData: {
      email,
      // if you don't want double opt in
      // set `double_opt_in` option to false
    }
  }, (err, _, body) => {
    if (err) {
      return callback(null, {
        statusCode: 500,
        body: JSON.stringify({
          message: `An unexpected (and rare) error has occured. Please contact us`,
          errorType: 'UNEXPECTED',
        }),
      });
    }
    if (body && body.error && body.error.email) {
      return callback(null, {
        statusCode: 400,
        body: JSON.stringify({
          message: `${email} is already a subscriber`,
          errorType: 'EMAIL_EXISTS',
        }),
      });
    }
    return callback(null, {
      statusCode: 200,
      body: JSON.stringify({
        message: 'You\'re all set! Please check your emails for our confirmation link!',
      }),
    });
  });
};