feat: Customisable Email Templates (#1095)

Gemfile

@@ -8,7 +8,7 @@ gem 'rails'
 # Reduces boot times through caching; required in config/boot.rb
 gem 'bootsnap', require: false
 
-##-- rails helper gems --##
+##-- rails application helper gems --##
 gem 'acts-as-taggable-on'
 gem 'attr_extras'
 gem 'browser'
@@ -23,6 +23,12 @@ gem 'tzinfo-data'
 gem 'valid_email2'
 # compress javascript config.assets.js_compressor
 gem 'uglifier'
+##-- used for single column multiple binary flags in notification settings/feature flagging --##
+gem 'flag_shih_tzu'
+# Random name generator for user names
+gem 'haikunator'
+# Template parsing safetly
+gem 'liquid'
 
 ##-- for active storage --##
 gem 'aws-sdk-s3', require: false
@@ -67,8 +73,6 @@ gem 'twitty'
 gem 'koala'
 # slack client
 gem 'slack-ruby-client'
-# Random name generator
-gem 'haikunator'
 
 ##--- gems for debugging and error reporting ---##
 # static analysis
@@ -79,9 +83,6 @@ gem 'sentry-raven'
 ##-- background job processing --##
 gem 'sidekiq'
 
-##-- used for single column multiple binary flags in notification settings/feature flagging --##
-gem 'flag_shih_tzu'
-
 ##-- Push notification service --##
 gem 'fcm'
 gem 'webpush'

Gemfile.lock

@@ -275,6 +275,7 @@ GEM
       addressable (~> 2.7)
     letter_opener (1.7.0)
       launchy (~> 2.2)
+    liquid (4.0.3)
     listen (3.2.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -584,6 +585,7 @@ DEPENDENCIES
   kaminari
   koala
   letter_opener
+  liquid
   listen
   mini_magick
   mock_redis!

app/drops/account_drop.rb

@@ -0,0 +1,2 @@
+class AccountDrop < BaseDrop
+end

app/drops/base_drop.rb

@@ -0,0 +1,13 @@
+class BaseDrop < Liquid::Drop
+  def initialize(obj)
+    @obj = obj
+  end
+
+  def id
+    @obj.try(:id)
+  end
+
+  def name
+    @obj.try(:name)
+  end
+end

app/drops/conversation_drop.rb

@@ -0,0 +1,5 @@
+class ConversationDrop < BaseDrop
+  def display_id
+    @obj.try(:display_id)
+  end
+end

app/drops/inbox_drop.rb

@@ -0,0 +1,2 @@
+class InboxDrop < BaseDrop
+end

app/drops/user_drop.rb

@@ -0,0 +1,2 @@
+class UserDrop < BaseDrop
+end

app/mailers/agent_notifications/conversation_notifications_mailer.rb

@@ -1,14 +1,12 @@
 class AgentNotifications::ConversationNotificationsMailer < ApplicationMailer
-  default from: ENV.fetch('MAILER_SENDER_EMAIL', 'accounts@chatwoot.com')
-  layout 'mailer'
-
   def conversation_creation(conversation, agent)
     return unless smtp_config_set_or_development?
 
     @agent = agent
     @conversation = conversation
     subject = "#{@agent.available_name}, A new conversation [ID - #{@conversation.display_id}] has been created in #{@conversation.inbox&.name}."
-    mail(to: @agent.email, subject: subject)
+    @action_url = app_account_conversation_url(account_id: @conversation.account_id, id: @conversation.display_id)
+    send_mail_with_liquid(to: @agent.email, subject: subject) and return
   end
 
   def conversation_assignment(conversation, agent)
@@ -16,6 +14,18 @@ class AgentNotifications::ConversationNotificationsMailer < ApplicationMailer
 
     @agent = agent
     @conversation = conversation
-    mail(to: @agent.email, subject: "#{@agent.available_name}, A new conversation [ID - #{@conversation.display_id}] has been assigned to you.")
+    subject = "#{@agent.available_name}, A new conversation [ID - #{@conversation.display_id}] has been assigned to you."
+    @action_url = app_account_conversation_url(account_id: @conversation.account_id, id: @conversation.display_id)
+    send_mail_with_liquid(to: @agent.email, subject: subject) and return
+  end
+
+  private
+
+  def liquid_droppables
+    super.merge({
+                  user: @agent,
+                  conversation: @conversation,
+                  inbox: @conversation.inbox
+                })
   end
 end

app/mailers/application_mailer.rb

@@ -1,9 +1,13 @@
 class ApplicationMailer < ActionMailer::Base
-  default from: ENV.fetch('MAILER_SENDER_EMAIL', 'accounts@chatwoot.com')
+  include ActionView::Helpers::SanitizeHelper
-  layout 'mailer'
-  append_view_path Rails.root.join('app/views/mailers')
 
-  # helpers
+  default from: ENV.fetch('MAILER_SENDER_EMAIL', 'accounts@chatwoot.com')
+  before_action { ensure_current_account(params.try(:[], :account)) }
+  layout 'mailer/base'
+  # Fetch template from Database if available
+  # Order: Account Specific > Installation Specific > Fallback to file
+  prepend_view_path ::EmailTemplate.resolver
+  append_view_path Rails.root.join('app/views/mailers')
   helper :frontend_urls
   helper do
     def global_config
@@ -14,4 +18,36 @@ class ApplicationMailer < ActionMailer::Base
   def smtp_config_set_or_development?
     ENV.fetch('SMTP_ADDRESS', nil).present? || Rails.env.development?
   end
+
+  private
+
+  def send_mail_with_liquid(*args)
+    mail(*args) do |format|
+      # explored sending a multipart email containg both text type and html
+      # parsing the html with nokogiri will remove the links as well
+      # might also remove tags like b,li etc. so lets rethink about this later
+      # format.text { Nokogiri::HTML(render(layout: false)).text }
+      format.html { render }
+    end
+  end
+
+  def liquid_droppables
+    # Merge additional objects into this in your mailer
+    # liquid template handler converts these objects into drop objects
+    {
+      account: Current.account
+    }
+  end
+
+  def liquid_locals
+    # expose variables you want to be exposed in liquid
+    {
+      global_config: GlobalConfig.get('INSTALLATION_NAME', 'BRAND_URL'),
+      action_url: @action_url
+    }
+  end
+
+  def ensure_current_account(account)
+    Current.account = account if account.present?
+  end
 end

app/mailers/conversation_reply_mailer.rb

@@ -105,6 +105,6 @@ class ConversationReplyMailer < ApplicationMailer
   def choose_layout
     return false if action_name == 'reply_without_summary'
 
-    'mailer'
+    'mailer/base'
   end
 end

app/models/application_record.rb

@@ -1,3 +1,10 @@
 class ApplicationRecord < ActiveRecord::Base
   self.abstract_class = true
+  DROPPABLES = %w[Account Channel Conversation Inbox User].freeze
+
+  def to_drop
+    return unless DROPPABLES.include?(self.class.name)
+
+    "#{self.class.name}Drop".constantize.new(self)
+  end
 end

app/models/conversation.rb

@@ -52,8 +52,10 @@ class Conversation < ApplicationRecord
 
   before_create :set_display_id, unless: :display_id?
   before_create :set_bot_conversation
-  after_create :notify_conversation_creation
+  after_create_commit :notify_conversation_creation
   after_save :run_round_robin
+  # wanted to change this to after_update commit. But it ended up creating a loop
+  # reinvestigate in future and identity the implications
   after_update :notify_status_change, :create_activity
 
   acts_as_taggable_on :labels

app/models/email_template.rb

@@ -0,0 +1,28 @@
+# == Schema Information
+#
+# Table name: email_templates
+#
+#  id            :bigint           not null, primary key
+#  body          :text             not null
+#  locale        :integer          default("en"), not null
+#  name          :string           not null
+#  template_type :integer          default("content")
+#  created_at    :datetime         not null
+#  updated_at    :datetime         not null
+#  account_id    :integer
+#
+# Indexes
+#
+#  index_email_templates_on_name_and_account_id  (name,account_id) UNIQUE
+#
+class EmailTemplate < ApplicationRecord
+  enum locale: LANGUAGES_CONFIG.map { |key, val| [val[:iso_639_1_code], key] }.to_h
+  enum template_type: { layout: 0, content: 1 }
+  belongs_to :account, optional: true
+
+  validates :name, uniqueness: { scope: :account }
+
+  def self.resolver(options = {})
+    ::EmailTemplates::DbResolverService.using self, options
+  end
+end

app/services/email_templates/db_resolver_service.rb

@@ -0,0 +1,87 @@
+# Code is heavily inspired by panaromic gem
+# https://github.com/andreapavoni/panoramic
+# We will try to find layouts and content from database
+# layout will be rendered with erb and other content in html format
+# Further processing in liquid is implemented in mailers
+
+# Note: rails resolver looks for templates in cache first
+# which we don't want to happen here
+# so we are overriding find_all method in action view resolver
+# If anything breaks - look into rails : actionview/lib/action_view/template/resolver.rb
+
+class ::EmailTemplates::DbResolverService < ActionView::Resolver
+  require 'singleton'
+  include Singleton
+
+  # Instantiate Resolver by passing a model.
+  def self.using(model, options = {})
+    class_variable_set(:@@model, model)
+    class_variable_set(:@@resolver_options, options)
+    instance
+  end
+
+  # Since rails picks up files from cache. lets override the method
+  # Normalizes the arguments and passes it on to find_templates.
+  # rubocop:disable Metrics/ParameterLists
+  def find_all(name, prefix = nil, partial = false, details = {}, key = nil, locals = [])
+    locals = locals.map(&:to_s).sort!.freeze
+    _find_all(name, prefix, partial, details, key, locals)
+  end
+  # rubocop:enable Metrics/ParameterLists
+
+  # the function has to accept(name, prefix, partial, _details, _locals = [])
+  # _details contain local info which we can leverage in future
+  # cause of codeclimate issue with 4 args, relying on (*args)
+  def find_templates(name, prefix, partial, *_args)
+    @template_name = name
+    @template_type = prefix.include?('layout') ? 'layout' : 'content'
+    @db_template = find_db_template
+
+    return [] if @db_template.blank?
+
+    path = build_path(prefix)
+    handler = ActionView::Template.registered_template_handler(:liquid)
+
+    template_details = {
+      format: Mime['html'].to_sym,
+      updated_at: @db_template.updated_at,
+      virtual_path: virtual_path(path, partial)
+    }
+
+    [ActionView::Template.new(@db_template.body, "DB Template - #{@db_template.id}", handler, template_details)]
+  end
+
+  private
+
+  def find_db_template
+    find_account_template || find_installation_template
+  end
+
+  def find_account_template
+    return unless Current.account
+
+    @@model.find_by(name: @template_name, template_type: @template_type, account: Current.account)
+  end
+
+  def find_installation_template
+    @@model.find_by(name: @template_name, template_type: @template_type, account: nil)
+  end
+
+  # Build path with eventual prefix
+  def build_path(prefix)
+    prefix.present? ? "#{prefix}/#{@template_name}" : @template_name
+  end
+
+  # returns a path depending if its a partial or template
+  # params path: path/to/file.ext  partial: true/false
+  # the function appends _to make the file name _file.ext if partial: true
+  def virtual_path(path, partial)
+    return path unless partial
+
+    if (index = path.rindex('/'))
+      path.insert(index + 1, '_')
+    else
+      "_#{path}"
+    end
+  end
+end

app/services/notification/email_notification_service.rb

@@ -8,7 +8,7 @@ class Notification::EmailNotificationService
 
     # TODO : Clean up whatever happening over here
     # Segregate the mailers properly
-    AgentNotifications::ConversationNotificationsMailer.public_send(notification
+    AgentNotifications::ConversationNotificationsMailer.with(account: notification.account).public_send(notification
       .notification_type.to_s, notification.primary_actor, notification.user).deliver_now
   end
 

app/views/layouts/mailer/base.liquid

@@ -81,7 +81,7 @@
                             <td class="content-wrap" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0; padding: 20px;" valign="top">
                                 <meta itemprop="name" content="Confirm Email" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;" />
                                 <table width="100%" cellpadding="0" cellspacing="0" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
-                                    <%= yield %>
+                                    {{ content_for_layout }}
                                 </table>
                             </td>
                         </tr>
@@ -89,16 +89,16 @@
                     <div class="footer" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; width: 100%; clear: both; color: #999; margin: 0; padding: 20px;">
                         <table width="100%" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
                             <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
-                                <% if global_config['BRAND_NAME'].present? %>
+                                {% if global_config['BRAND_NAME'] %}
                                     <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
                                         <td class="content-block" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0; padding: 0 0 20px;" valign="top">
                                             Powered by
-                                            <a href="<%= global_config['BRAND_URL'] %>" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; color: #999; text-align: center; margin: 0; padding: 0 0 20px;" align="center" valign="top">
+                                            <a href="{{ global_config['BRAND_URL'] }}" style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; color: #999; text-align: center; margin: 0; padding: 0 0 20px;" align="center" valign="top">
-                                                <%= global_config['BRAND_NAME'] %>
+                                                {{ global_config['BRAND_NAME'] }}
                                             </a>
                                         </td>
                                     </tr>
-                                <% end %>
+                                {% endif %}
                             </tr>
                         </table>
                     </div>

app/views/mailers/agent_notifications/conversation_notifications_mailer/conversation_assignment.html.erb

@@ -1,10 +0,0 @@
-<p>Hi <%= @agent.available_name %>,</p>
-
-<p>Time to save the world. A new conversation has been assigned to you</p>
-
-<p>
-Click <%=
-  link_to 'here',
-  app_account_conversation_url(account_id: @conversation.account_id, id: @conversation.display_id)
-%> to get cracking.
-</p>

app/views/mailers/agent_notifications/conversation_notifications_mailer/conversation_assignment.liquid

@@ -0,0 +1,7 @@
+<p>Hi {{user.available_name}},</p>
+
+<p>Time to save the world. A new conversation has been assigned to you</p>
+
+<p>
+Click <a href="{{action_url}}">here</a> to get cracking.
+</p>

app/views/mailers/agent_notifications/conversation_notifications_mailer/conversation_creation.html.erb

@@ -1,10 +0,0 @@
-<p>Hi <%= @agent.available_name %>,</p>
-
-<p>Time to save the world. A new conversation has been created in <%= @conversation.inbox.name %></p>
-
-<p>
-Click <%=
-  link_to 'here',
-  app_account_conversation_url(account_id: @conversation.account_id, id: @conversation.display_id)
-%> to get cracking.
-</p>

app/views/mailers/agent_notifications/conversation_notifications_mailer/conversation_creation.liquid

@@ -0,0 +1,8 @@
+<p>Hi {{user.available_name}}</p>
+
+
+<p>Time to save the world. A new conversation has been created in {{ inbox.name }}</p>
+
+<p>
+Click <a href="{{ action_url }}">here</a> to get cracking.
+</p>

config/initializers/liquid_handler.rb

@@ -0,0 +1 @@
+ActionView::Template.register_template_handler :liquid, ActionView::Template::Handlers::Liquid

db/migrate/20200725131651_create_email_templates.rb

@@ -0,0 +1,13 @@
+class CreateEmailTemplates < ActiveRecord::Migration[6.0]
+  def change
+    create_table :email_templates do |t|
+      t.string :name, null: false
+      t.text :body, null: false
+      t.integer :account_id, null: true
+      t.integer :template_type, default: 1
+      t.integer :locale, default: 0, null: false
+      t.timestamps
+    end
+    add_index :email_templates, [:name, :account_id], unique: true
+  end
+end

db/schema.rb

@@ -231,6 +231,17 @@ ActiveRecord::Schema.define(version: 2020_08_02_170002) do
     t.index ["contact_inbox_id"], name: "index_conversations_on_contact_inbox_id"
   end
 
+  create_table "email_templates", force: :cascade do |t|
+    t.string "name", null: false
+    t.text "body", null: false
+    t.integer "account_id"
+    t.integer "template_type", default: 1
+    t.integer "locale", default: 0, null: false
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["name", "account_id"], name: "index_email_templates_on_name_and_account_id", unique: true
+  end
+
   create_table "events", force: :cascade do |t|
     t.string "name"
     t.float "value"

lib/action_view/template/handlers/liquid.rb

@@ -0,0 +1,62 @@
+# Code inspired by
+# http://royvandermeij.com/blog/2011/09/21/create-a-liquid-handler-for-rails-3-dot-1/
+# https://github.com/chamnap/liquid-rails/blob/master/lib/liquid-rails/template_handler.rb
+
+class ActionView::Template::Handlers::Liquid
+  def self.call(template, _source)
+    "ActionView::Template::Handlers::Liquid.new(self).render(#{template.source.inspect}, local_assigns)"
+  end
+
+  def initialize(view)
+    @view       = view
+    @controller = @view.controller
+    @helper     = ActionController::Base.helpers
+  end
+
+  def render(template, local_assigns = {})
+    assigns = drops
+    assigns['content_for_layout'] = @view.content_for(:layout) if @view.content_for?(:layout)
+    assigns.merge!(local_assigns)
+    assigns.merge!(locals)
+
+    liquid = Liquid::Template.parse(template)
+    liquid.send(render_method, assigns.stringify_keys, filters: filters, registers: registers.stringify_keys)
+  end
+
+  def locals
+    if @controller.respond_to?(:liquid_locals, true)
+      @controller.send(:liquid_locals)
+    else
+      {}
+    end
+  end
+
+  def drops
+    droppables = @controller.send(:liquid_droppables) if @controller.respond_to?(:liquid_droppables, true)
+    droppables.update(droppables) { |_, obj| obj.try(:to_drop) || nil }
+  end
+
+  def filters
+    if @controller.respond_to?(:liquid_filters, true)
+      @controller.send(:liquid_filters)
+    else
+      []
+    end
+  end
+
+  def registers
+    if @controller.respond_to?(:liquid_registers, true)
+      @controller.send(:liquid_registers)
+    else
+      {}
+    end
+  end
+
+  def compilable?
+    false
+  end
+
+  def render_method
+    ::Rails.env.development? || ::Rails.env.test? ? :render! : :render
+  end
+end

spec/factories/email_template.rb

@@ -0,0 +1,5 @@
+FactoryBot.define do
+  factory :email_template do
+    name { 'MyString' }
+  end
+end

spec/lib/email_templates/db_resolver_service_spec.rb

@@ -0,0 +1,80 @@
+require 'rails_helper'
+
+describe ::EmailTemplates::DbResolverService do
+  subject(:resolver) { described_class.using(EmailTemplate, {}) }
+
+  describe '#find_templates' do
+    context 'when template does not exist in db' do
+      it 'return empty array' do
+        expect(resolver.find_templates('test', '', false, [])).to eq([])
+      end
+    end
+
+    context 'when installation template exist in db' do
+      it 'return installation template' do
+        email_template = create(:email_template, name: 'test', body: 'test')
+        handler = ActionView::Template.registered_template_handler(:liquid)
+        template_details = {
+          format: Mime['html'].to_sym,
+          updated_at: email_template.updated_at,
+          virtual_path: 'test'
+        }
+
+        expect(
+          resolver.find_templates('test', '', false, []).first.to_json
+        ).to eq(
+          ActionView::Template.new(
+            email_template.body,
+            "DB Template - #{email_template.id}", handler, template_details
+          ).to_json
+        )
+      end
+    end
+
+    context 'when account template exists in db' do
+      let(:account) { create(:account) }
+      let(:installation_template) { create(:email_template, name: 'test', body: 'test') }
+      let(:account_template) { create(:email_template, name: 'test', body: 'test2', account: account) }
+
+      it 'return account template for current account' do
+        Current.account = account
+        handler = ActionView::Template.registered_template_handler(:liquid)
+        template_details = {
+          format: Mime['html'].to_sym,
+          updated_at: account_template.updated_at,
+          virtual_path: 'test'
+        }
+
+        expect(
+          resolver.find_templates('test', '', false, []).first.to_json
+        ).to eq(
+          ActionView::Template.new(
+            account_template.body,
+            "DB Template - #{account_template.id}", handler, template_details
+          ).to_json
+        )
+        Current.account = nil
+      end
+
+      it 'return installation template when  current account dont have template' do
+        Current.account = create(:account)
+        handler = ActionView::Template.registered_template_handler(:liquid)
+        template_details = {
+          format: Mime['html'].to_sym,
+          updated_at: installation_template.updated_at,
+          virtual_path: 'test'
+        }
+
+        expect(
+          resolver.find_templates('test', '', false, []).first.to_json
+        ).to eq(
+          ActionView::Template.new(
+            installation_template.body,
+            "DB Template - #{installation_template.id}", handler, template_details
+          ).to_json
+        )
+        Current.account = nil
+      end
+    end
+  end
+end

spec/mailers/confirmation_instructions_spec.rb

@@ -31,6 +31,7 @@ RSpec.describe 'Confirmation Instructions', type: :mailer do
         expect(mail.body).to match(
           "#{CGI.escapeHTML(inviter_val.name)}, with #{CGI.escapeHTML(inviter_val.account.name)}, has invited you to try out Chatwoot!"
         )
+        Current.account = nil
       end
     end
   end