Rails ガイド

$ bin/rails generate mailer User
create  app/mailers/user_mailer.rb
invoke  erb
create    app/views/user_mailer
invoke  test_unit
create    test/mailers/user_mailer_test.rb
create    test/mailers/previews/user_mailer_preview.rb

# app/mailers/user_mailer.rb
class UserMailer < ApplicationMailer
end

# app/mailers/application_mailer.rb
class ApplicationMailer < ActionMailer::Base
  default from: "from@example.com"
  layout 'mailer'
end

# app/mailers/custom_mailer.rb
class CustomMailer < ApplicationMailer
end

class UserMailer < ApplicationMailer
  default from: "notifications@example.com"

  def welcome_email
    @user = params[:user]
    @url  = "http://example.com/login"
    mail(to: @user.email, subject: "私の素敵なサイトへようこそ")
  end
end

$ bin/rails generate mailer User welcome_email

<h1><%= @user.name %>様、example.comへようこそ。</h1>
<p>
  example.comへのサインアップが成功しました。
  ユーザー名は「<%= @user.login %>」です。<br>
</p>
<p>
  このサイトにログインするには、次のリンクをクリックしてください: <%= link_to 'login`, login_url %>
</p>
<p>本サイトにユーザー登録いただきありがとうございます。</p>

<%= @user.name %>様、example.comへようこそ。
===============================================

example.comへのサインアップが成功しました。ユーザー名は「<%= @user.login %>」です。

このサイトにログインするには、次のリンクをクリックしてください: <%= @url %>

本サイトにユーザー登録いただきありがとうございます。

$ bin/rails generate scaffold user name email login
$ bin/rails db:migrate

class UsersController < ApplicationController
  # ...

  def create
    @user = User.new(user_params)

    respond_to do |format|
      if @user.save
        # 保存後にUserMailerを使ってwelcomeメールを送信
        UserMailer.with(user: @user).welcome_email.deliver_later

        format.html { redirect_to user_url(@user), notice: "ユーザーが正常に作成されました" }
        format.json { render :show, status: :created, location: @user }
      else
        format.html { render :new, status: :unprocessable_entity }
        format.json { render json: @user.errors, status: :unprocessable_entity }
      end
    end
  end

  # ...
end

[ActiveJob] [ActionMailer::MailDeliveryJob] [ec4b3786-b9fc-4b5e-8153-9153095e1cbf] Delivered mail 6661f55087e34_1380c7eb86934d@Bhumis-MacBook-Pro.local.mail (19.9ms)
[ActiveJob] [ActionMailer::MailDeliveryJob] [ec4b3786-b9fc-4b5e-8153-9153095e1cbf] Date: Thu, 06 Jun 2024 12:43:44 -0500
From: notifications@example.com
To: test@gmail.com
Message-ID: <6661f55087e34_1380c7eb86934d@Bhumis-MacBook-Pro.local.mail>
Subject: Welcome to My Awesome Site
Mime-Version: 1.0
Content-Type: multipart/alternative;
 boundary="--==_mimepart_6661f55086194_1380c7eb869259";
 charset=UTF-8
Content-Transfer-Encoding: 7bit

----==_mimepart_6661f55086194_1380c7eb869259
Content-Type: text/plain;

...

----==_mimepart_6661f55086194_1380c7eb869259
Content-Type: text/html;

...

irb> user = User.first
irb> UserMailer.with(user: user).welcome_email.deliver_later

class SendWeeklySummary
  def run
    User.find_each do |user|
      UserMailer.with(user: user).weekly_summary.deliver_now
    end
  end
end

irb> UserMailer.with(user: user).weekly_summary
#<ActionMailer::MailDeliveryJob:0x00007f84cb0367c0
 @_halted_callback_hook_called=nil,
 @_scheduled_at_time=nil,
 @arguments=
  ["UserMailer",
   "welcome_email",
   "deliver_now",
   {:params=>
     {:user=>
       #<User:0x00007f84c9327198
        id: 1,
        name: "Bhumi",
        email: "hi@gmail.com",
        login: "Bhumi",
        created_at: Thu, 06 Jun 2024 17:43:44.424064000 UTC +00:00,
        updated_at: Thu, 06 Jun 2024 17:43:44.424064000 UTC +00:00>},
    :args=>[]}],
 @exception_executions={},
 @executions=0,
 @job_id="07747748-59cc-4e88-812a-0d677040cd5a",
 @priority=nil,

attachments['filename.jpg'] = File.read('/path/to/filename.jpg')

encoded_content = SpecialEncode(File.read('/path/to/filename.jpg'))
attachments['filename.jpg'] = {
  mime_type: 'application/gzip',
  encoding: 'SpecialEncoding',
  content: encoded_content
}

def welcome
  attachments.inline['image.jpg'] = File.read('/path/to/image.jpg')
end

<p>こんにちは、リクエストいただいた写真は以下です:</p>

<%= image_tag attachments['image.jpg'].url %>

<p>こんにちは、以下の写真です。</p>

<%= image_tag attachments['image.jpg'].url, alt: 'My Photo', class: 'photos' %>

class UserMailer < ApplicationMailer
  default from: 'notifications@example.com'

  def welcome_email
    @user = params[:user]
    @url  = 'http://example.com/login'
    mail(to: @user.email,
         subject: '私の素敵なサイトへようこそ',
         template_path: 'notifications',
         template_name: 'hello')
  end
end

class UserMailer < ApplicationMailer
  default from: 'notifications@example.com'

  def welcome_email
    @user = params[:user]
    @url  = 'http://example.com/login'
    mail(to: @user.email,
         subject: '私の素敵なサイトへようこそ') do |format|
      format.html { render 'another_template' }
      format.text { render plain: 'hello' }
    end
  end
end

class UserMailer < ApplicationMailer
  prepend_view_path "custom/path/to/mailer/view"

  # "custom/path/to/mailer/view/welcome_email" テンプレートの読み出しを試みる
  def welcome_email
    # ...
  end
end

config.action_mailer.default_url_options = { host: 'example.com' }

<%= link_to 'ようこそ', welcome_path %>

<%= link_to 'ようこそ', welcome_url %>

<%= url_for(host: 'example.com',
            controller: 'welcome',
            action: 'greeting') %>

<%= user_url(@user, host: 'example.com') %>

config.action_mailer.asset_host = 'http://example.com'

<%= image_tag 'image.jpg' %>

<% cache do %>
  <%= @company.name %>
<% end %>

config.action_mailer.perform_caching = true

# app/views/layouts/mailer.html.erb
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <style>
      /* Email styles need to be inline */
    </style>
  </head>

  <body>
    <%= yield %>
  </body>
</html>

class UserMailer < ApplicationMailer
  layout 'awesome' # awesome.(html|text).erbをレイアウトとして使う
end

class UserMailer < ApplicationMailer
  def welcome_email
    mail(to: params[:user].email) do |format|
      format.html { render layout: 'my_layout' }
      format.text
    end
  end
end

class AdminMailer < ApplicationMailer
  default to: -> { Admin.pluck(:email) },
          from: 'notification@example.com'

  def new_registration(user)
    @user = user
    mail(subject: "New User Signup: #{@user.email}")
  end
end

def welcome_email
  @user = params[:user]
  mail(
    to: email_address_with_name(@user.email, @user.name),
    subject: '私の素敵なサイトへようこそ'
  )
end

class UserMailer < ApplicationMailer
  default from: email_address_with_name('notification@example.com', '会社からのお知らせの例')
end

class UserMailer < ApplicationMailer
  def welcome_email
    mail(to: params[:user].email,
         body: params[:email_body],
         content_type: "text/html",
         subject: "レンダリング完了")
  end
end

class UserMailer < ApplicationMailer
  def welcome_email
    @user = params[:user]
    @url  = user_url(@user)
    delivery_options = { user_name: params[:company].smtp_user,
                         password: params[:company].smtp_password,
                         address: params[:company].smtp_host }
    mail(to: @user.email,
         subject: "添付の利用規約を参照してください",
         delivery_method_options: delivery_options)
  end
end

class InvitationsMailer < ApplicationMailer
  before_action :set_inviter_and_invitee
  before_action { @account = params[:inviter].account }

  default to:       -> { @invitee.email_address },
          from:     -> { common_address(@inviter) },
          reply_to: -> { @inviter.email_address_with_name }

  def account_invitation
    mail subject: "#{@inviter.name} をBasecampに招待いたします (#{@account.name})"
  end

  def project_invitation
    @project    = params[:project]
    @summarizer = ProjectInvitationSummarizer.new(@project.bucket)

    mail subject: "#{@inviter.name.familiar} をBasecampのプロジェクトに追加しました (#{@account.name})"
  end

  private
    def set_inviter_and_invitee
      @inviter = params[:inviter]
      @invitee = params[:invitee]
    end
end

class UserMailer < ApplicationMailer
  before_action { @business, @user = params[:business], params[:user] }

  after_action :set_delivery_options,
               :prevent_delivery_to_guests,
               :set_business_headers

  def feedback_message
  end

  def campaign_message
  end

  private
    def set_delivery_options
      # ここではメールのインスタンスや
      # @businessや@userインスタンス変数にアクセスできる
      if @business && @business.has_smtp_settings?
        mail.delivery_method.settings.merge!(@business.smtp_settings)
      end
    end

    def prevent_delivery_to_guests
      if @user && @user.guest?
        mail.perform_deliveries = false
      end
    end

    def set_business_headers
      if @business
        headers["X-SMTPAPI-CATEGORY"] = @business.code
      end
    end
end

class UserMailer < ApplicationMailer
  after_deliver :mark_delivered
  before_deliver :sandbox_staging
  after_deliver :observe_delivery

  def feedback_message
    @feedback = params[:feedback]
  end

  private
    def mark_delivered
      params[:feedback].touch(:delivered_at)
    end

    # インターセプタの代替
    def sandbox_staging
      message.to = ['sandbox@example.com'] if Rails.env.staging?
    end

    # コールバックは、同様のオブザーバーの例よりも多くのコンテキストを含む
    def observe_delivery
      EmailDelivery.log(message, self.class, action_name, params)
    end
end

<%= stylesheet_link_tag mailer.name.underscore %>
<h1><%= message.subject %></h1>

config.action_mailer.delivery_method = :sendmail
# デフォルトは以下:
# config.action_mailer.sendmail_settings = {
#   location: '/usr/sbin/sendmail',
#   arguments: %w[ -i ]
# }
config.action_mailer.perform_deliveries = true
config.action_mailer.raise_delivery_errors = true
config.action_mailer.default_options = { from: 'no-reply@example.com' }

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address:         'smtp.gmail.com',
  port:            587,
  domain:          'example.com',
  user_name:       Rails.application.credentials.dig(:smtp, :user_name),
  password:        Rails.application.credentials.dig(:smtp, :password),
  authentication:  'plain',
  enable_starttls: true,
  open_timeout:    5,
  read_timeout:    5 }

class UserMailerPreview < ActionMailer::Preview
  def welcome_email
    UserMailer.with(user: User.first).welcome_email
  end
end

config.action_mailer.preview_paths << "#{Rails.root}/lib/mailer_previews"

class NotifierMailer < ApplicationMailer
  rescue_from ActiveJob::DeserializationError do
    # ...
  end

  rescue_from "SomeThirdPartyService::ApiError" do
    # ...
  end

  def notify(recipient)
    mail(to: recipient, subject: "Notification")
  end
end

class SandboxEmailInterceptor
  def self.delivering_email(message)
    message.to = ['sandbox@example.com']
  end
end

Rails.application.configure do
  if Rails.env.staging?
    config.action_mailer.interceptors = %w[SandboxEmailInterceptor]
  end
end

class EmailDeliveryObserver
  def self.delivered_email(message)
    EmailDelivery.log(message)
  end
end

Rails.application.configure do
  config.action_mailer.observers = %w[EmailDeliveryObserver]
end