Send emails with a Bootstrap template using Gmail

In this tutorial, we are going to use Rails ActionMailer and Gmail to send emails with bootstrap styling. This tutorial has 2 parts, first is setting up the ActionMailer and Gmail and the second part is setting up bootstrap email template.

Set up Mailer

Generate a mailer

rails g mailer sample_mailer

This will generate a ruby app/mailers/sample_mailer.rb file and a directory app/views/sample_mailer for SampleMailer's view files.
The app/mailers/sample_mailer.rb file looks like

class SampleMailer < ApplicationMailer
  default from: "from@example.com"
end

Change the from@example.com with the Gmail account email which you want to use for sending emails, and then write a method that will construct the email. We've named the method welcome_email(which will construct a very dull welcome email for the sake of this tutorial).

class SampleMailer < ActionMailer::Base
  default from: "your_email_here@gmail.com"

  def welcome_email(welcome_message, name, email_to, subject)
    @message = welcome_message
    @name = name
    make_bootstrap_mail(to: email_to, subject: subject)
  end
end

Gmail configuration

Write the following config in your /config/environments/production.rb or /config/environments/development.rb (whichever you're going to use for sending the emails, of course you can use both; in that case put the config in both the files)

config.action_mailer.delivery_method = :smtp
# SMTP settings for gmail
config.action_mailer.smtp_settings = {
  address: 'smtp.gmail.com',
  port: 587,
  user_name: ENV['GMAIL_USERNAME'],
  password: ENV['GMAIL_PASSWORD'],
  authentication: 'plain',
  enable_starttls_auto: true
}

Gmail username and password are sensitive data so we have stored them in the environment variables, for the rails development environment, you can set up environment variables by using the Dotenv gem or Figaro gem. Don't forget to restart server after setting up environment variables.

Enable Gmail's Less secure apps setting

Go to this settings link and enable less secure apps. Without enabling this setting Gmail won't let you send emails from your app.

Set up Bootstrap email template

Include the bootstrap-email gem

Add this to your Gemfile

gem 'bootstrap-email'

and then do

bundle install

Create bootstrap layout file

Create a file /app/views/layouts/bootstrap-mailer.html.erb and paste the following HTML into it. This file will act as a container file for the mailer views that you're going to render.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <%= stylesheet_link_tag "application-mailer", media: "all" %>
  </head>
  <body class="bg-light">
    <%= yield %>
  </body>
</html>

Tell mailer to use the Bootstrap email layout

Specifying this in the ApplicationMailer class configures the layout option for all the descendants of the ApplicationMailer class

# app/mailers/application_mailer.rb

class ApplicationMailer < ActionMailer::Base
  layout 'bootstrap-mailer'
end

Create stylesheet for bootstrap email template

Create a new stylesheet /app/assets/stylesheets/application-mailer.scss and import bootstrap-email. This is where your custom styles and overrides that you want to be inlined should live.

// /app/assets/stylesheets/application-mailer.scss

@import 'bootstrap-email';

Precompiling the stylesheet

Add this line in /config/initializers/asset.rb to compile your new SASS file.

Rails.application.config.assets.precompile += %w( application-mailer.scss )

Create the view file

Create the view file /app/views/sample_mailer/welcome_email.html.erb. Any instance variables you had in the welcome_email method in the file app/views/products_mailer/sample_email.html.erb can be used in this view file.
Let's use this as an example view file for sending the email.

<div class="card">
  <div class="card-header">
    Welcome
  </div>
  <div class="card-body">
    <h5 class="card-title">Welcome <%= name %></h5>
    <p class="card-text"><%= welcome_message %></p>
    <a href="#" class="btn btn-primary">Platform</a>
  </div>
</div>

And finally, send the email

To send the email, you need to do this in your application

welcome_message = "Hello your're welcome to our platform!"
name = current_user.name
email_to = current_user.email
subject = 'Welcome Email'

SampleMailer.welcome_email(welcome_message, name, email_to, subject).deliver if email_to

References

The resources used for creating this tutorial are listed below

Cover Image credits: Mathyas Kurmann on Unsplash

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