Mail Interceptor

TOC

• Mail Interceptor
  • TOC
  • About
  • Usage
  • only_intercept
  • deliver_emails_to
  • forward_emails_to
  • ignore_bcc and ignore_cc
  • Custom Environment
  • Prefixing email with subject
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About

This gem intercepts and forwards email to a forwarding address in a non-production environment. This is to ensure that in staging or in development by mistake we do not deliver emails to the real people. However we need to test emails time to time.

Refer to https://github.com/bigbinary/wheel/blob/master/config/initializers/mail_interceptor.rb and you will notice that if an email ends with deliver@bigbinary.com then that emaill will be delivered.

So if Neeraj wants to test how the real email looks then he can use email neeraj+deliver@bigbinary.com and that email will be delivered. As long as an email ends with deliver@bigbinary.com then that email will not be intercepted.

If client wants to test something and the client expects an email to be delivered then we need to add client's email here. Say the client's email is michael@timbaktu.com. Change that line to deliver_emails_to: ["deliver@bigbinary.com", "timbaktu.com"]. Now all emails ending with timbaktu.com would be delivered. If you want only Michael should get email and other emails ending with "timbaktu.com" to be intercepted then change that line to deliver_emails_to: ["deliver@bigbinary.com", "michael@timbaktu.com"].

Usage

# There is no need to include this gem for production or for test environment
gem 'mail_interceptor', group: [:development, :staging]

# config/initializers/mail_interceptor.rb

options = { forward_emails_to: 'intercepted_emails@domain.com',
            deliver_emails_to: ["@wheel.com"] }

unless (Rails.env.test? || Rails.env.production?)
  interceptor = MailInterceptor::Interceptor.new(options)
  ActionMailer::Base.register_interceptor(interceptor)
end

Do not use this feature in test mode so that in tests you can test against provided recipients of the email.

only_intercept

Passing only_intercept is optional. If only_intercept is passed then only emails having the pattern mentioned in only_intercept will be intercepted. Rest of the emails will be delivered.

Let's say you want to only intercept emails ending with @bigbinary.com and forward the email. Here's how it can be accomplished.

MailInterceptor::Interceptor.new({ forward_emails_to: 'intercepted_emails@domain.com',
                                   only_intercept:  ["@bigbinary.com"] })

This will only intercept emails ending with @bigbinary.com and forward the emails. Every other email will be delivered.

Suppose you want to intercept only some emails and not deliver them. You can do that by only passing the only_intercept option like so:

MailInterceptor::Interceptor.new({ only_intercept: ["@bigbinary.com"] })

This will intercept emails ending with @bigbinary and not deliver them.

deliver_emails_to

Passing deliver_emails_to is optional. If no deliver_emails_to is passed then all emails will be intercepted and forwarded in non-production environment.

Let's say you want to actually deliver all emails having the pattern "@BigBinary.com". Here is how it can be accomplished.

MailInterceptor::Interceptor.new({ forward_emails_to: 'intercepted_emails@domain.com',
                                   deliver_emails_to: ["@bigbinary.com"] })

If you want the emails to be delivered only if the email address is qa@bigbinary.com then that can be done too.

MailInterceptor::Interceptor.new({ forward_emails_to: 'intercepted_emails@domain.com',
                                   deliver_emails_to: ["qa@bigbinary.com"] })

Now only qa@bigbinary.com will get its emails delivered and all other emails will be intercepted and forwarded.

The regular expression is matched without case sensitive. So you can mix lowercase and uppercase and it won't matter.

forward_emails_to

Passing forward_emails_to is optional. If no forward_emails_to is passed then all emails will be intercepted and only emails matching with deliver_emails_to will be delivered.

Blank options can be provided to intercept and not send any emails.

MailInterceptor::Interceptor.new({})

It can take a single email or an array of emails.

MailInterceptor::Interceptor.new({ forward_emails_to: 'intercepted_emails@bigbinary.com' })

It can also take an array of emails in which case emails are forwarded to each of those emails in the array.

MailInterceptor::Interceptor.new({ forward_emails_to: ['intercepted_emails@bigbinary.com',
                                                       'qa@bigbinary.com' })

ignore_bcc and ignore_cc

By default bcc and cc are ignored. You can pass :ignore_bcc or :ignore_cc options as false, if you don't want to ignore bcc or cc.

Custom Environment

By default all emails sent in non production environment are intercepted. However you can control this behavior by passing env as the key. It accepts any ruby objects which responds to intercept? method. If the result of that method is true then emails are intercepted otherwise emails are not intercepted.

Below is an example of how to pass a custom ruby object as value for env key.

Besides method intercept? method name is needed if you have provided subject_prefix. This name will be appended to the subject_prefix to produce something like [WHEEL STAGING] Forgot password. In this case STAGING came form name.

class MyEnv
  def name
    ENV["ENVIRONMENT_NAME"]
  end

  def intercept?
    ENV["INTERCEPT_MAIL"] == '1'
  end
end

MailInterceptor::Interceptor.new({ env: MyEnv.new,
                                   forward_emails_to: ['intercepted_emails@bigbinary.com',
                                   'qa@bigbinary.com' })

Prefixing email with subject

If you are looking for automatically prefix all delivered emails with the application name and Rails environment then we recommend using email_prefixer gem .

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