Implement Newsletter bulk delivery

Author: rossta

app/controllers/admin/newsletters_controller.rb

@@ -1,5 +1,5 @@
 class Admin::NewslettersController < ApplicationController
-  before_action :set_newsletter, only: %i[show edit update destroy]
+  before_action :set_newsletter, only: %i[show edit update destroy deliver]
 
   # GET /admin/newsletters
   def index
@@ -45,6 +45,21 @@ def destroy
     redirect_to admin_newsletter_url, notice: "Newsletter was successfully destroyed.", status: :see_other
   end
 
+  # PATCH /admin/newsletters/1/deliver
+  def deliver
+    @newsletter = Newsletter.find(params[:id])
+    recipients = deliver_live? ? User.subscribers : User.where(email: ApplicationMailer.test_recipients)
+    label = deliver_live? ? "LIVE" : "TEST"
+
+    if recipients.empty?
+      return redirect_to [:admin, @newsletter], alert: "No recipients found."
+    end
+
+    NewsletterNotifier.deliver_to(recipients, newsletter: @newsletter)
+
+    redirect_to [:admin, @newsletter], notice: "[#{label}] Newsletter was successfully delivered."
+  end
+
   private
 
   # Use callbacks to share common setup or constraints between actions.
@@ -56,4 +71,6 @@ def set_newsletter
   def newsletter_params
     params.fetch(:newsletter, {}).permit(:title, :content)
   end
+
+  def deliver_live? = params[:live] == "true"
 end

app/jobs/notifications/event_job.rb

@@ -2,6 +2,8 @@ class Notifications::EventJob < ApplicationJob
   queue_as :default
 
   def perform(event)
+    event.deliver_notifications_in_bulk
+
     # Enqueue individual deliveries
     event.notifications.each do |notification|
       notification.transaction do

app/mailers/application_mailer.rb

@@ -9,8 +9,8 @@ class ApplicationMailer < ActionMailer::Base
   default from: email_address_with_name(FROM_ADDRESS, FROM_NAME)
   layout "emails/mailer"
 
-  def self.test_recipient_email
-    Rails.configuration.settings.emails.test_recipient
+  def self.test_recipients
+    [Rails.configuration.settings.emails.test_recipient].compact
   end
 
   def support_email

app/mailers/emails/newsletter_mailer.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class Emails::NewsletterMailer < ApplicationMailer
+  NEWSLETTER_EMAIL = Rails.configuration.settings.emails.broadcast_from_address
+
+  default from: email_address_with_name(
+    Rails.configuration.settings.emails.broadcast_from_address,
+    "Ross from Joy of Rails"
+  )
+
+  def newsletter(newsletter:, user:, unsubscribe_token:)
+    @newsletter = newsletter
+    @user = user
+    @unsubscribe_token = unsubscribe_token
+
+    headers["MESSAGE-STREAM"] = "broadcast"
+
+    mail(to: user.email, subject: newsletter.title)
+  end
+end

app/models/notification_event.rb

@@ -14,6 +14,7 @@ def self.dump(data)
   end
 
   has_many :notifications, dependent: :delete_all
+  has_many :recipients, through: :notifications, source: :recipient, source_type: "User"
 
   accepts_nested_attributes_for :notifications
 
@@ -69,7 +70,11 @@ def recipient_attributes_for(recipient)
     }
   end
 
+  def deliver_notifications_in_bulk
+    # no op
+  end
+
   def deliver_notification(notification)
-    raise NotImplementedError, "Subclasses must implement #deliver_notification"
+    # no op
   end
 end

app/models/user.rb

@@ -8,7 +8,9 @@ class User < ApplicationRecord
 
   has_one :newsletter_subscription, as: :subscriber, dependent: :destroy
 
+  scope :confirmed, -> { where.not(confirmed_at: nil) }
   scope :recently_confirmed, -> { where("confirmed_at > ?", 2.weeks.ago) }
+  scope :subscribers, -> { confirmed.joins(:newsletter_subscription) }
 
   accepts_nested_attributes_for :email_exchanges, limit: 1
 

app/notifiers/newsletter_notifier.rb

@@ -0,0 +1,42 @@
+class NewsletterNotifier < NotificationEvent
+  def self.deliver_to(users, newsletter:, **)
+    new(params: {newsletter_id: newsletter.id}).deliver(users, **)
+  end
+
+  def deliver_notifications_in_bulk
+    newsletter = Newsletter.find(params[:newsletter_id])
+    messages = build_newsletter_messages(newsletter)
+
+    PostmarkClient.deliver_messages(messages)
+
+    newsletter.touch(:sent_at)
+  end
+
+  private
+
+  def postmark_client
+    @postmark_client ||= Postmark::ApiClient.new(Rails.configuration.settings.postmark_api_token)
+  end
+
+  def build_newsletter_messages(newsletter)
+    recipients.find_each.filter_map do |user|
+      if !user.confirmed?
+        log_skip(newsletter, user, "user not confirmed")
+        next
+      end
+
+      unsubscribe_token = user&.newsletter_subscription&.generate_token_for(:unsubscribe)
+
+      if !unsubscribe_token
+        log_skip(newsletter, user, "could not generate unsubscribe token")
+        next
+      end
+
+      Emails::NewsletterMailer.newsletter(newsletter:, user:, unsubscribe_token:)
+    end
+  end
+
+  def log_skip(newsletter, user, reason)
+    Rails.logger.info "#[#{self.class}] Skipping delivery of newsletter #{newsletter.id} for: #{user.class.name}##{user.id} — #{reason}"
+  end
+end

app/views/admin/newsletters/show.html.erb

@@ -1,5 +1,10 @@
 <%= render Pages::Header.new(title: "Admin: #{@newsletter.title}") %>
 <div class="section-content container py-gap">
+  <div class="flex gap-x-2">
+    <%= button_to "Send Test", deliver_admin_newsletter_path(@newsletter), class: "button secondary" %>
+    <%= button_to "Send Live", deliver_admin_newsletter_path(@newsletter, live: true), class: "button primary" %>
+  </div>
+
   <%= render @newsletter %>
 
   <div>

app/views/components/markdown/base.rb

@@ -86,6 +86,8 @@ def visit(node)
       html_block(node.to_html(options: @options))
     in :html_inline # This is a raw HTML inline element, so we skip here in safe mode
       html_inline(node.to_html(options: @options))
+    in :strikethrough
+      s { visit_children(node) }
     end
   end
 

app/views/emails/newsletter_mailer/newsletter.html.erb

@@ -0,0 +1 @@
+<%= render Markdown::Base.new(@newsletter.content.html_safe) %>