Handle incoming email with Griddler

Joel Oliveira


FYI: We have updated Griddler instructions in Griddler is Better Than Ever!

For all the likes, shares, tweets, pokes, follows, and friends, there’s a fundamental core to the internet that, no matter how hard some might hope, will never go away—email. Rails has built-in support for outgoing mail with ActionMailer, but nothing on the omakase menu handles incoming mail. To help with that, we extracted Griddler from Trajectory and are now happy to release it—hot off the… ahem… presses.

Griddler is a Rails engine that provides an endpoint for the SendGrid Parse API. It hands off a preprocessed email object to a class implemented by you. We’re happy to look at pull requests that interface with other email services.


To get Griddler integrated with your app, add Griddler to your Gemfile, and bundle away:

gem 'griddler'

Griddler automatically adds an endpoint to your routes table resembling the following:

post '/email_processor' => 'griddler/emails#create'

But you may copy, paste, and modify that anywhere else in your routes for the purposes of your application.

Once Sendgrid posts to your endpoint Griddler will take care of packaging up the important bits of that data and providing a nice Griddler::Email object for you. The contract we expect you to go in on with Griddler at this point is that you will implement a class called EmailProcessor, containing a class method called process, which we will be passing that packaged up instance of Griddler::Email into.

For example, in lib/email_processor.rb:

class EmailProcessor
  def self.process(email)
    # all of your application-specific code here - creating models,
    # processing reports, etc

The email object contains the following attributes:

  • to
  • from
  • subject
  • body
  • raw_body

Of those, to, from, and subject fall on the obvious side as to their purpose.

Let your users interact with your app via email

What isn’t entirely obvious (but very cool) is that Griddler helps you handle the email body by cleaning up replies and providing the important parts of an email before -- Reply ABOVE THIS LINE -- in the body attribute. Note that the reply delimiter is adjustable in the configuration. We keep raw_body around, as contains everything before Griddler scrubs it into body so that you may use the contents for other purposes.

There is much more information in the Griddler README explaining the details, configuration, testing, and other bits.

If you like it, let us know what you think! As always, you can find the code on GitHub. We look forward to hearing all of the ways you use Griddler!