From f76eac56b9d7d4ae61010cddcca68682824b2239 Mon Sep 17 00:00:00 2001
From: Douwe Maan <douwe@gitlab.com>
Date: Tue, 18 Aug 2015 15:46:36 -0700
Subject: [PATCH] Reply by email POC

---
 .gitignore                                    |  1 +
 Gemfile                                       |  2 +
 Gemfile.lock                                  |  8 +++
 Procfile                                      |  3 +-
 app/mailers/emails/issues.rb                  |  8 +++
 app/mailers/emails/merge_requests.rb          | 11 +++-
 app/mailers/emails/notes.rb                   |  6 +++
 app/mailers/notify.rb                         | 54 ++++++++++++-------
 app/models/sent_notification.rb               | 29 ++++++++++
 app/workers/email_receiver_worker.rb          | 22 ++++++++
 config/gitlab.yml.example                     |  5 ++
 config/initializers/1_settings.rb             |  6 +++
 config/mail_room.yml.example                  | 14 +++++
 .../20150818213832_add_sent_notifications.rb  | 13 +++++
 db/schema.rb                                  | 13 ++++-
 lib/gitlab/email_receiver.rb                  | 50 +++++++++++++++++
 16 files changed, 224 insertions(+), 21 deletions(-)
 create mode 100644 app/models/sent_notification.rb
 create mode 100644 app/workers/email_receiver_worker.rb
 create mode 100644 config/mail_room.yml.example
 create mode 100644 db/migrate/20150818213832_add_sent_notifications.rb
 create mode 100644 lib/gitlab/email_receiver.rb

diff --git a/.gitignore b/.gitignore
index 3e30fb8cf77..8a68bb3e4f0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,7 @@ config/initializers/rack_attack.rb
 config/initializers/smtp_settings.rb
 config/resque.yml
 config/unicorn.rb
+config/mail_room.yml
 coverage/*
 db/*.sqlite3
 db/*.sqlite3-journal
diff --git a/Gemfile b/Gemfile
index 8f65a274baa..e3f76671f5b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -272,3 +272,5 @@ end
 gem "newrelic_rpm"
 
 gem 'octokit', '3.7.0'
+
+gem "mail_room", github: "DouweM/mail_room", branch: "sidekiq"
diff --git a/Gemfile.lock b/Gemfile.lock
index f0c661fa9c5..3aca2c8890b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,3 +1,10 @@
+GIT
+  remote: git://github.com/DouweM/mail_room.git
+  revision: e1795b807f492533ad40afcb80abf870f1baddb5
+  branch: sidekiq
+  specs:
+    mail_room (0.3.1)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -805,6 +812,7 @@ DEPENDENCIES
   jquery-ui-rails
   kaminari (~> 0.15.1)
   letter_opener
+  mail_room!
   minitest (~> 5.3.0)
   mousetrap-rails
   mysql2
diff --git a/Procfile b/Procfile
index 799b92729fa..51154f150d1 100644
--- a/Procfile
+++ b/Procfile
@@ -1,2 +1,3 @@
 web: bundle exec unicorn_rails -p ${PORT:="3000"} -E ${RAILS_ENV:="development"} -c ${UNICORN_CONFIG:="config/unicorn.rb"}
-worker: bundle exec sidekiq -q post_receive -q mailer -q archive_repo -q system_hook -q project_web_hook -q gitlab_shell -q common -q default
+worker: bundle exec sidekiq -q post_receive -q mailer -q archive_repo -q system_hook -q project_web_hook -q gitlab_shell -q incoming_email -q common -q default
+mail_room: bundle exec mail_room -c config/mail_room.yml
diff --git a/app/mailers/emails/issues.rb b/app/mailers/emails/issues.rb
index 687bac3aa31..c8b7775c328 100644
--- a/app/mailers/emails/issues.rb
+++ b/app/mailers/emails/issues.rb
@@ -8,6 +8,8 @@ module Emails
                       from: sender(@issue.author_id),
                       to: recipient(recipient_id),
                       subject: subject("#{@issue.title} (##{@issue.iid})"))
+
+      sent_notification!(@issue, recipient_id)
     end
 
     def reassigned_issue_email(recipient_id, issue_id, previous_assignee_id, updated_by_user_id)
@@ -19,6 +21,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@issue.title} (##{@issue.iid})"))
+
+      sent_notification!(@issue, recipient_id)
     end
 
     def closed_issue_email(recipient_id, issue_id, updated_by_user_id)
@@ -30,6 +34,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@issue.title} (##{@issue.iid})"))
+
+      sent_notification!(@issue, recipient_id)
     end
 
     def issue_status_changed_email(recipient_id, issue_id, status, updated_by_user_id)
@@ -42,6 +48,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@issue.title} (##{@issue.iid})"))
+
+      sent_notification!(@issue, recipient_id)
     end
   end
 end
diff --git a/app/mailers/emails/merge_requests.rb b/app/mailers/emails/merge_requests.rb
index 512a8f7ea6b..7a685c04ebc 100644
--- a/app/mailers/emails/merge_requests.rb
+++ b/app/mailers/emails/merge_requests.rb
@@ -10,6 +10,8 @@ module Emails
                       from: sender(@merge_request.author_id),
                       to: recipient(recipient_id),
                       subject: subject("#{@merge_request.title} (##{@merge_request.iid})"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
 
     def reassigned_merge_request_email(recipient_id, merge_request_id, previous_assignee_id, updated_by_user_id)
@@ -23,6 +25,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@merge_request.title} (##{@merge_request.iid})"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
 
     def closed_merge_request_email(recipient_id, merge_request_id, updated_by_user_id)
@@ -36,6 +40,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@merge_request.title} (##{@merge_request.iid})"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
 
     def merged_merge_request_email(recipient_id, merge_request_id, updated_by_user_id)
@@ -48,6 +54,8 @@ module Emails
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@merge_request.title} (##{@merge_request.iid})"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
 
     def merge_request_status_email(recipient_id, merge_request_id, status, updated_by_user_id)
@@ -58,11 +66,12 @@ module Emails
       @target_url = namespace_project_merge_request_url(@project.namespace,
                                                         @project,
                                                         @merge_request)
-      set_reference("merge_request_#{merge_request_id}")
       mail_answer_thread(@merge_request,
                          from: sender(updated_by_user_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@merge_request.title} (##{@merge_request.iid}) #{@mr_status}"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
   end
 
diff --git a/app/mailers/emails/notes.rb b/app/mailers/emails/notes.rb
index ff251209e01..2612074a5ff 100644
--- a/app/mailers/emails/notes.rb
+++ b/app/mailers/emails/notes.rb
@@ -11,6 +11,8 @@ module Emails
                          from: sender(@note.author_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@commit.title} (#{@commit.short_id})"))
+
+      sent_notification!(@commit, recipient_id)
     end
 
     def note_issue_email(recipient_id, note_id)
@@ -24,6 +26,8 @@ module Emails
                          from: sender(@note.author_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@issue.title} (##{@issue.iid})"))
+
+      sent_notification!(@issue, recipient_id)
     end
 
     def note_merge_request_email(recipient_id, note_id)
@@ -38,6 +42,8 @@ module Emails
                          from: sender(@note.author_id),
                          to: recipient(recipient_id),
                          subject: subject("#{@merge_request.title} (##{@merge_request.iid})"))
+
+      sent_notification!(@merge_request, recipient_id)
     end
   end
 end
diff --git a/app/mailers/notify.rb b/app/mailers/notify.rb
index 79fb48b00d3..44df3d6407d 100644
--- a/app/mailers/notify.rb
+++ b/app/mailers/notify.rb
@@ -46,6 +46,17 @@ class Notify < ActionMailer::Base
     allowed_domains
   end
 
+  def sent_notification!(noteable, recipient_id)
+    return unless reply_key
+
+    SentNotification.create(
+      project: noteable.project,
+      noteable: noteable,
+      recipient_id: recipient_id,
+      reply_key: reply_key
+    )
+  end
+
   private
 
   # The default email address to send emails from
@@ -85,14 +96,6 @@ class Notify < ActionMailer::Base
     @current_user.notification_email
   end
 
-  # Set the References header field
-  #
-  # local_part - The local part of the referenced message ID
-  #
-  def set_reference(local_part)
-    headers["References"] = "<#{local_part}@#{Gitlab.config.gitlab.host}>"
-  end
-
   # Formats arguments into a String suitable for use as an email subject
   #
   # extra - Extra Strings to be inserted into the subject
@@ -130,10 +133,23 @@ class Notify < ActionMailer::Base
   # with headers suitable for grouping by thread in email clients.
   #
   # See: mail_answer_thread
-  def mail_new_thread(model, headers = {}, &block)
+  def mail_new_thread(model, headers = {})
+    if @project
+      headers['X-GitLab-Project'] = @project.name 
+      headers['X-GitLab-Project-Id'] = @project.id
+      headers['X-GitLab-Project-Path'] = @project.path_with_namespace
+    end
+
+    headers["X-GitLab-#{model.class.name}-ID"] = model.id
+
     headers['Message-ID'] = message_id(model)
-    headers['X-GitLab-Project'] = "#{@project.name} | " if @project
-    mail(headers, &block)
+
+    if reply_key
+      headers['X-GitLab-Reply-Key'] = reply_key
+      headers['Reply-To'] = Gitlab.config.reply_by_email.address.gsub('%{reply_key}', reply_key)
+    end
+
+    mail(headers)
   end
 
   # Send an email that responds to an existing conversation thread,
@@ -144,19 +160,21 @@ class Notify < ActionMailer::Base
   #  * have a subject that begin by 'Re: '
   #  * have a 'In-Reply-To' or 'References' header that references the original 'Message-ID'
   #
-  def mail_answer_thread(model, headers = {}, &block)
+  def mail_answer_thread(model, headers = {})
+    headers['Message-ID'] = SecureRandom.hex
     headers['In-Reply-To'] = message_id(model)
     headers['References'] = message_id(model)
-    headers['X-GitLab-Project'] = "#{@project.name} | " if @project
 
-    if headers[:subject]
-      headers[:subject].prepend('Re: ')
-    end
-
-    mail(headers, &block)
+    mail_new_thread(model, headers)
   end
 
   def can?
     Ability.abilities.allowed?(user, action, subject)
   end
+
+  def reply_key
+    return nil unless Gitlab.config.reply_by_email.enabled
+
+    @reply_key ||= SecureRandom.hex(16)
+  end
 end
diff --git a/app/models/sent_notification.rb b/app/models/sent_notification.rb
new file mode 100644
index 00000000000..a3d24669b52
--- /dev/null
+++ b/app/models/sent_notification.rb
@@ -0,0 +1,29 @@
+class SentNotification < ActiveRecord::Base
+  belongs_to :project
+  belongs_to :noteable, polymorphic: true
+  belongs_to :recipient, class_name: "User"
+
+  validate :project, :recipient, :reply_key, presence: true
+  validate :reply_key, uniqueness: true
+
+  validates :noteable_id, presence: true, if: ->(n) { n.noteable_type.present? && n.noteable_type != 'Commit' }
+  validates :commit_id, presence: true, if: ->(n) { n.noteable_type == 'Commit' }
+
+  def self.for(reply_key)
+    find_by(reply_key: reply_key)
+  end
+
+  def for_commit?
+    noteable_type == "Commit"
+  end
+
+  def noteable
+    if for_commit?
+      project.commit(commit_id)
+    else
+      super
+    end
+  rescue
+    nil
+  end
+end
diff --git a/app/workers/email_receiver_worker.rb b/app/workers/email_receiver_worker.rb
new file mode 100644
index 00000000000..e44a430f6bc
--- /dev/null
+++ b/app/workers/email_receiver_worker.rb
@@ -0,0 +1,22 @@
+class EmailReceiverWorker
+  include Sidekiq::Worker
+
+  sidekiq_options queue: :incoming_email
+
+  def perform(raw)
+    return unless Gitlab.config.reply_by_email.enabled
+
+    # begin
+      Gitlab::EmailReceiver.new(raw).process
+    # rescue => e
+    #   handle_failure(raw, e)
+    # end
+  end
+
+  private
+
+  def handle_failure(raw, e)
+    # TODO: Handle better.
+    Rails.logger.warn("Email can not be processed: #{e}\n\n#{raw}")
+  end
+end
diff --git a/config/gitlab.yml.example b/config/gitlab.yml.example
index 56770335ddc..e78429b29a3 100644
--- a/config/gitlab.yml.example
+++ b/config/gitlab.yml.example
@@ -94,6 +94,11 @@ production: &base
     # The default is 'tmp/repositories' relative to the root of the Rails app.
     # repository_downloads_path: tmp/repositories
 
+  ## Reply by email
+  reply_by_email:
+    enabled: false
+    address: "replies+%{reply_key}@gitlab.example.com"
+
   ## Gravatar
   ## For Libravatar see: http://doc.gitlab.com/ce/customization/libravatar.html
   gravatar:
diff --git a/config/initializers/1_settings.rb b/config/initializers/1_settings.rb
index 026c1a5792c..9e83660e103 100644
--- a/config/initializers/1_settings.rb
+++ b/config/initializers/1_settings.rb
@@ -149,6 +149,12 @@ Settings.gitlab.default_projects_features['visibility_level']    = Settings.send
 Settings.gitlab['repository_downloads_path'] = File.absolute_path(Settings.gitlab['repository_downloads_path'] || 'tmp/repositories', Rails.root)
 Settings.gitlab['restricted_signup_domains'] ||= []
 
+#
+# Reply by email
+#
+Settings['reply_by_email'] ||= Settingslogic.new({})
+Settings.reply_by_email['enabled'] = false if Settings.gravatar['enabled'].nil?
+
 #
 # Gravatar
 #
diff --git a/config/mail_room.yml.example b/config/mail_room.yml.example
new file mode 100644
index 00000000000..a7a6a25362e
--- /dev/null
+++ b/config/mail_room.yml.example
@@ -0,0 +1,14 @@
+:mailboxes:
+  # -
+  #   :host: "imap.gmail.com"
+  #   :port: 993
+  #   :ssl: true
+  #   :email: "replies@gitlab.example.com"
+  #   :password: "password"
+  #   :name: "inbox"
+  #   :delivery_method: sidekiq
+  #   :delivery_options:
+  #     :redis_url: redis://localhost:6379
+  #     :namespace: resque:gitlab
+  #     :queue: incoming_email
+  #     :worker: EmailReceiverWorker
diff --git a/db/migrate/20150818213832_add_sent_notifications.rb b/db/migrate/20150818213832_add_sent_notifications.rb
new file mode 100644
index 00000000000..43e8d6a1a82
--- /dev/null
+++ b/db/migrate/20150818213832_add_sent_notifications.rb
@@ -0,0 +1,13 @@
+class AddSentNotifications < ActiveRecord::Migration
+  def change
+    create_table :sent_notifications do |t|
+      t.references :project
+      t.references :noteable, polymorphic: true
+      t.references :recipient
+      t.string :commit_id
+      t.string :reply_key, null: false
+    end
+
+    add_index :sent_notifications, :reply_key, unique: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 6e919f2883b..0827e810f18 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150806104937) do
+ActiveRecord::Schema.define(version: 20150818213832) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -404,6 +404,17 @@ ActiveRecord::Schema.define(version: 20150806104937) do
 
   add_index "protected_branches", ["project_id"], name: "index_protected_branches_on_project_id", using: :btree
 
+  create_table "sent_notifications", force: true do |t|
+    t.integer "project_id"
+    t.integer "noteable_id"
+    t.string  "noteable_type"
+    t.integer "recipient_id"
+    t.string  "commit_id"
+    t.string  "reply_key",     null: false
+  end
+
+  add_index "sent_notifications", ["reply_key"], name: "index_sent_notifications_on_reply_key", unique: true, using: :btree
+
   create_table "services", force: true do |t|
     t.string   "type"
     t.string   "title"
diff --git a/lib/gitlab/email_receiver.rb b/lib/gitlab/email_receiver.rb
new file mode 100644
index 00000000000..a9f67bb5da0
--- /dev/null
+++ b/lib/gitlab/email_receiver.rb
@@ -0,0 +1,50 @@
+module Gitlab
+  class EmailReceiver
+    def initialize(raw)
+      @raw = raw
+    end
+
+    def message
+      @message ||= Mail::Message.new(@raw)
+    end
+
+    def process
+      return unless message && sent_notification
+
+      Notes::CreateService.new(
+        sent_notification.project,
+        sent_notification.recipient,
+        note:           message.text_part.to_s,
+        noteable_type:  sent_notification.noteable_type,
+        noteable_id:    sent_notification.noteable_id,
+        commit_id:      sent_notification.commit_id
+      ).execute
+    end
+
+    private
+
+    def reply_key
+      address = Gitlab.config.reply_by_email.address
+      return nil unless address
+
+      regex = Regexp.escape(address)
+      regex = regex.gsub(Regexp.escape('%{reply_key}'), "(.*)")
+      regex = Regexp.new(regex)
+
+      address = message.to.find { |address| address =~ regex }
+      return nil unless address
+
+      match = address.match(regex)
+        
+      return nil unless match && match[1].present?
+
+      match[1]
+    end
+
+    def sent_notification
+      return nil unless reply_key
+      
+      SentNotification.for(reply_key)
+    end
+  end
+end