Mailers

Amber V2 includes Amber::Mailer::Base, MIME generation, attachments, an in-memory delivery adapter, and SMTP delivery. Generate an ECR-backed mailer with the standalone CLI.

Run from: the application root.

amber generate mailer Digest --actions=weekly

The generator writes src/mailers/digest_mailer.cr, an ECR template under src/views/digest_mailer/, and a mailer spec. The generated class implements the required HTML and text bodies.

File: src/mailers/digest_mailer.cr — edit the generated class in place.

class DigestMailer < Amber::Mailer::Base
  def initialize(@user_name : String, @user_email : String)
  end

  def html_body : String?
    ECR.render("src/views/digest_mailer/weekly.ecr")
  end

  def text_body : String?
    "Hello, #{@user_name}!"
  end
end

File: src/views/digest_mailer/weekly.ecr — edit the generated HTML body and escape user-provided values.

<h1>Hello, <%= HTML.escape(@user_name) %>!</h1>

Delivery configuration

The memory adapter is the default and is appropriate for tests. Configure SMTP at application startup before delivering production mail.

File: config/application.cr — append this configuration after require "amber".

Amber::Mailer::Configuration.configure do |config|
  config.adapter = :smtp
  config.smtp_host = ENV["SMTP_HOST"]
  config.smtp_port = ENV.fetch("SMTP_PORT", "587").to_i
  config.smtp_username = ENV["SMTP_USERNAME"]?
  config.smtp_password = ENV["SMTP_PASSWORD"]?
  config.use_tls = true
  config.default_from = ENV.fetch("MAIL_FROM", "[email protected]")
  config.helo_domain = ENV.fetch("SMTP_HELO_DOMAIN", "localhost")
end

Do not commit SMTP credentials.

Build and deliver

File: the controller action or job that owns delivery, for example src/jobs/digest_delivery_job.cr — build the message before calling .deliver.

result = DigestMailer.new("Alice", "[email protected]")
  .to("[email protected]")
  .subject("Your weekly digest")
  .deliver

raise result.error.to_s unless result.is_successful

Use .from, .cc, .bcc, .reply_to, .header, .attach, or .attach_file before .deliver when the message needs them. The Quartz-Mailer and Slang examples on the V1 page do not describe Amber V2's mailer API.