Track Opened Emails In Rails

article logo

Tracking opened emails is a technique that, if used responsibly, can provide utility to both you and your users.
Here a few use cases where it makes sense to me:

  • Appointment updates. If your appointment in a car dealership was rescheduled an email is sent. If the email is not read in the next couple of hours a repeat email can be sent or a CS agent may follow up with a call.
  • Uber-style fulfillment, where contractors are notified of lucrative jobs available to them. If nobody claims a job, a CS agent can go through users who are known not to have read the email.
  • Providing estimates to event organizers how many people are going to show up based a on number of opened emails.

In this article, we are going to implement such a system for transactional emails using Rails and Postmark (a service that sends emails). We are going to use the Postmark gem.

Usage

First of all, let's see how the code usage of the tool we are building is going to look like:

def new_blog_post(blog_post, subscriber)
    store_message(
      email_name: 'new_blog_post',
      entity: blog_post,
      user: subscriber
    )

    mail(
      to: subscriber.email,
      subject: "New Post: #{blog_post.title}",
      track_opens: 'true'
    )
end

all_emails = blog_post.sent_emails.count
opened_emails = blog_post.sent_emails.opened.count
open_rate = opened_emails.fdiv(all_emails)

What is a tracking pixel?

By adding track_opens: 'true' you are instructing Postmark to include a unique 1x1 image in the email. When a user opens that email the image gets loaded, which notifies the Postmark that the email was opened. It may not always work depending on an email client and user's settings.

Implementation

Setup

To track email status we are going to create records in a database table:

The next step is to define a callback that's going to be executed any time an email is sent, for that we need to add the following code to initializers:

Mailer

To pass these params from our mailer we need to define the store_message method.
With this code any time we successfully send an email we are also going to create a record in the sent_emails table.

Webhooks

The next step is to start accepting webhooks from Postmark.

Let's define a webhook for opening an email, then do a similar thing for bounced emails.

And controller code that's going to handle these webhooks:

Here's how these services are implemented:

That is all, use responsibly, and thank you for reading!

p.s. you can see the full example repo here.

Popular posts from this blog

HTTP server in Ruby 3 - Fibers & Ractors

Image
This is part #2. Head over to part #1 to learn about HTTP in Ruby. Motivation Historically Ruby's been lacking in the concurrency department. Ruby has "native" threads (prior to 1.9 there were only "green"), which means there can be multiple threads controlled by an OS, but only 1 thread can be executed at a time, this is managed via Global Interpreter Lock (GIL). However, native calls and I/O calls can be executed in parallel. During an I/O call, a thread gives up control and waits for a signal that the I/O has finished. This means I/O heavy applications can benefit from multiple threads. In this article we are going to explore different concurrency modes for our HTTP server: Single-threaded Multi-threaded Fibers Ractors Single-threaded Let's start simple and see how a single threaded HTTP server could look like ( full code ): def start socket = TCPServer.new(HOST, PORT) sock
Read more

Next.js: restrict pages to authenticated users

Image
Many websites have pages that need to be restricted to authenticated users, for example profile pages or dashboards. Next.js web framework comes with a lot of functionality built-in JS compilation, rendering code on server and caching. When it comes to most other aspecs, it's up to a programmer to build, including such needed functionality as restricting access to some pages only to authenticated users. In this article we are going to build just that: a function that augments a page object, that could be used like that: Here's the implementation in TypeScript: In order to make it work on server we are going to need one more utility function fetchWithCookies . When making HTTP request from inside a Web Browser, the browser automatically sends cookies with each requests and then stores new cookies if a response comes in with set-cookie header. On server-side we need to build this feature ourselves, because neither Next.js nor NodeJS make any a
Read more

Migration locks for TypeORM

Image
Schema migrations is a must-have functionality for any DB framework. TypeORM provides decent utilities for dealing with migrations, however having a decade of experience in Ruby on Rails I got really spoiled and take some features for granted. One of these features is locking a database while a migration going on so 2 processes running concurrently don't step on each other's toes. This is also important when you run migrations in Kubernetes before launching your app. I was really surprised to find out that this basic feature is not supported , so decided to implement it on my own. Implementation // typeormMigrationUtils.ts import { Connection, createConnection } from 'typeorm' import config from '../ormconfig' import CRC32 from 'crc-32' const MIGRATOR_SALT = 2053462845 async function withAdvisoryLock( connection: Connection, callback: () => Promise<void> ): Promise<boolean> { // generate a unique lock
Read more