How do I make ActiveMailer always mail me? - ruby-on-rails

Question

I use ActiveMailer with a 3rd party mailing provider. To develop my app, I want to actually see the emails that come in, as a user would, in my email client.
So in development mode, instead of disabling email, I want my app to send the mails, but change the "to" field so that every email is sent to me. Is that possible?
Update: I want to test the full route my email takes: going through my ESP, arriving in my inbox, viewing it in gmail. I'm not looking to just test that an email is created.

Answer 1

I personally recommend letter_opener by Ryan Bates, however, if you actually want to deliver the mail instead of just viewing it in the browser, there are a number of plugins available that others have already listed. No one, however, has mentioned that you can very easily accomplish this using Interceptors.
Create a new initializer in your config/initializers directory in your Rails app:
# config/initializers/development_mail_interceptor.rb
class DevelopmentMailInterceptor
def self.delivering_email(message)
message.subject = "[#{message.to}] #{message.subject}"
message.to = "YOUR_EMAIL#gmail.com"
end
end
ActionMailer::Base.register_interceptor(DevelopmentMailInterceptor) if Rails.env.development?
This leverages the power of an interceptor on your app. It doesn't configure anything, but rather changes the envelope on the message, altering the to and subject fields. Replace YOUR_EMAIL with the correct value.
The self.delivering_email(message) method is invoked by ActionMailer. You are hooking into that method and override the message envelope.
Finally, you register that interceptor iff we are currently in the development environment.
Be sure to restart your server, and all your mail (in Development) will actually be sent to your email.

Answer 2

Save yourself some trouble and run MailCatcher. MailCatcher is a simple SMTP server that just grabs outbound email and gives it to you in a simple web interface. Install MailCatcher, add this to your environments/development.rb:
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { :host => 'localhost', :port => 1025 }
Start MailCatcher when you start your Rails server (or use Foreman or something similar to deal with it), and then go to http://localhost:1080/ to see the email that your application is sending out.

Answer 3

You may consider checking out something like MockSMTP (OS X); instead of modifying your "to" fields, you instead set the mail server for dev mode to the "fake" SMTP server created by the app, and from then on ALL emails (sent to anyone) go instead to the app.
I've never used it myself, but I remember seeing that the devs at 37signals use it.
On other operating systems, you may consider one of the following projects:
letter_opener by Ryan Bates - popup a new browser window when an email is sent
MailCatcher (mentioned by mu is too short) - runs a fake SMTP server and a web-based interface for viewing mail sent to it
mailtrap - similar to MockSMTP, has both a mock SMTP server and also a separate viewer program

Answer 4

As much as I like this answer, I went with a different option.
Use the mail_safe gem! As well as providing the functionality from sethvargo's answer, it doesn't require any work other than adding the gem, and it automatically figures out who to email from their .gitconfig.
One important note that I rarely saw mentioned when researching this is that you must use deliver, not deliver!. The latter doesnt call interceptors (though apparently it still calls observers, if that's helpful).