It’s incredible how easy it is to send emails through a web application, there’s no wonder we get so much spam. Assuming we have a ruby app using Sinatra, Pony is one of the easiest ways to get started with your own spam empire.

Installation is, as always, trivial with ruby. Install the gem with gem install pony or add gem pony to your Gemfile and run bundle install.

I like to configure Pony in my application’s configure block. I could also add it to my config.ru, but I like to keep that file as tiny as posible to avoid having configuration code all over the place.

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# ...

require 'pony'
require 'sinatra/base'

class Application < Sinatra::Base
  configure do
    # ...

    Pony.options = {
      :via => :smtp,
      :via_options => {
        :address => 'smtp.sendgrid.net',
        :port => '587',
        :domain => 'myapp.com',
        :user_name => ENV['SENDGRID_USERNAME'],
        :password => ENV['SENDGRID_PASSWORD'],
        :authentication => :plain,
        :enable_starttls_auto => true
      }
    }
  end

  # ...
end

This block tells Pony to use the SendGrid server to send mail, use the “myapp.com” HELO domain, and dig up the username and password fields from my environment.

If you’re using Heroku to host your application, you can sign up for a SendGrid account through your Heroku app, which gives you instant access to your SendGrid account. The username and password field you need to fill in your environment are automatically populated in your Heroku config, which you can view by running heroku config for your application. The free account gets you up to 200 emails a day.

Since I might have multiple developers working in my source code and testing the email-sending functionality, I have all the developers sign up for their own free SendGrid account. This should help to alleviate some of the email volume from any particular account while developing. After signing up, it took my account nearly 4 hours to be “provisioned” (see: approved) by the SendGrid team. Once you’re approved you can start sending emails using your developer account credentials. I stick my username/password in my local .env file (another reason to make sure you’re not storing your environment on your server or in your git repo).

So let’s actually send an email. Let’s create a route that sends an email to verify a new user account; I’ll take some liberties by saying we have a User model defined already that generates a signup verification hash. I can tell pony to send a plaintext body through the body option and an HTML body through the html_body option.

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# ...
post '/signup' do
  user = User.create! params

  url = "#{request.base_url}/account/reset/#{user.generate_verification_hash}"
  Pony.mail(
    to: user.email,
    from: "MyApp Help Desk <noreply@myapp.com>",
    subject: "MyApp Account Verification",
    body: "A request has been made to verify your MyApp account (https://myapp.com)." +
          "If you made this request, go to " + url + ". If you did not make this request, ignore this email.",
    html_body: haml(
      :verify_account_email,
      layout: false,
      locals: {
        email: user.email,
        date: DateTime.now.strftime("%H:%M:%S%P %B %d, %Y"),
        ip: request.ip,
        url: url
      }
    )
  )
end

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%p
  Hello!
%p
  An account verification has been requested for your new <a href="https://myapp.com">MyApp</a> account.

%ul
  %li
    Username: #{locals[:email]}
  %li
    Time: #{locals[:date]}
  %li
    IP address: #{locals[:ip]}

%p
  If you made this request, click the link below or copy-paste the following URL into your browser to verify your account:

%p
  %a{href: "#{locals[:url]}", alt: "Verify", title: "Click to verify account"}
    #{locals[:url]}

%p
  If you did not request this new account, please ignore this email.

%p
  Sincerely,
  %br
  Team MyApp

%p
  This email account is not monitored and will not receive replies. For more information, contact <a href="mailto:connect@myapp.com">connect@myapp.com</a>.

When you have a user hit this route, an email will be sent to the user with the given subject, to, from, and body fields using the configuration parameters given in the previous configure block. Fast, easy, and, best of all, no sendmail configuration.