Handles unsubscribe from notifications via email

- allows unsubscription processing of email in format "reply+%{key}+unsubscribe@acme.com" (example)
- if config.address includes %{key} and replies are enabled every unsubscriable message will include mailto: link in its List-Unsubscribe header

6 files changed, 96 insertions, 44 deletions

diff --git a/lib/gitlab/email/handler.rb b/lib/gitlab/email/handler.rb
index bd3267e2a80..bd2f5d3615e 100644
--- a/lib/gitlab/email/handler.rb
+++ b/lib/gitlab/email/handler.rb
@@ -1,10 +1,11 @@
 require 'gitlab/email/handler/create_note_handler'
 require 'gitlab/email/handler/create_issue_handler'
+require 'gitlab/email/handler/unsubscribe_handler'
 
 module Gitlab
   module Email
     module Handler
-      HANDLERS = [CreateNoteHandler, CreateIssueHandler]
+      HANDLERS = [UnsubscribeHandler, CreateNoteHandler, CreateIssueHandler]
 
       def self.for(mail, mail_key)
         HANDLERS.find do |klass|
diff --git a/lib/gitlab/email/handler/base_handler.rb b/lib/gitlab/email/handler/base_handler.rb
index 7cccf465334..3f6ace0311a 100644
--- a/lib/gitlab/email/handler/base_handler.rb
+++ b/lib/gitlab/email/handler/base_handler.rb
@@ -9,52 +9,13 @@ module Gitlab
           @mail_key = mail_key
         end
 
-        def message
-          @message ||= process_message
-        end
-
-        def author
+        def can_execute?
           raise NotImplementedError
         end
 
-        def project
+        def execute
           raise NotImplementedError
         end
-
-        private
-
-        def validate_permission!(permission)
-          raise UserNotFoundError unless author
-          raise UserBlockedError if author.blocked?
-          raise ProjectNotFound unless author.can?(:read_project, project)
-          raise UserNotAuthorizedError unless author.can?(permission, project)
-        end
-
-        def process_message
-          message = ReplyParser.new(mail).execute.strip
-          add_attachments(message)
-        end
-
-        def add_attachments(reply)
-          attachments = Email::AttachmentUploader.new(mail).execute(project)
-
-          reply + attachments.map do |link|
-            "\n\n#{link[:markdown]}"
-          end.join
-        end
-
-        def verify_record!(record:, invalid_exception:, record_name:)
-          return if record.persisted?
-          return if record.errors.key?(:commands_only)
-
-          error_title = "The #{record_name} could not be created for the following reasons:"
-
-          msg = error_title + record.errors.full_messages.map do |error|
-            "\n\n- #{error}"
-          end.join
-
-          raise invalid_exception, msg
-        end
       end
     end
   end
diff --git a/lib/gitlab/email/handler/create_issue_handler.rb b/lib/gitlab/email/handler/create_issue_handler.rb
index 9f90a3ec2b2..127fae159d5 100644
--- a/lib/gitlab/email/handler/create_issue_handler.rb
+++ b/lib/gitlab/email/handler/create_issue_handler.rb
@@ -5,6 +5,7 @@ module Gitlab
   module Email
     module Handler
       class CreateIssueHandler < BaseHandler
+        include ReplyProcessing
         attr_reader :project_path, :incoming_email_token
 
         def initialize(mail, mail_key)
diff --git a/lib/gitlab/email/handler/create_note_handler.rb b/lib/gitlab/email/handler/create_note_handler.rb
index 447c7a6a6b9..d87ba427f4b 100644
--- a/lib/gitlab/email/handler/create_note_handler.rb
+++ b/lib/gitlab/email/handler/create_note_handler.rb
@@ -1,10 +1,13 @@
 
 require 'gitlab/email/handler/base_handler'
+require 'gitlab/email/handler/reply_processing'
 
 module Gitlab
   module Email
     module Handler
       class CreateNoteHandler < BaseHandler
+        include ReplyProcessing
+
         def can_handle?
           mail_key =~ /\A\w+\z/
         end
@@ -24,6 +27,8 @@ module Gitlab
             record_name: 'comment')
         end
 
+        private
+
         def author
           sent_notification.recipient
         end
@@ -36,8 +41,6 @@ module Gitlab
           @sent_notification ||= SentNotification.for(mail_key)
         end
 
-        private
-
         def create_note
           Notes::CreateService.new(
             project,
diff --git a/lib/gitlab/email/handler/reply_processing.rb b/lib/gitlab/email/handler/reply_processing.rb
new file mode 100644
index 00000000000..32c5caf93e8
--- /dev/null
+++ b/lib/gitlab/email/handler/reply_processing.rb
@@ -0,0 +1,54 @@
+module Gitlab
+  module Email
+    module Handler
+      module ReplyProcessing
+        private
+
+        def author
+          raise NotImplementedError
+        end
+
+        def project
+          raise NotImplementedError
+        end
+
+        def message
+          @message ||= process_message
+        end
+
+        def process_message
+          message = ReplyParser.new(mail).execute.strip
+          add_attachments(message)
+        end
+
+        def add_attachments(reply)
+          attachments = Email::AttachmentUploader.new(mail).execute(project)
+
+          reply + attachments.map do |link|
+            "\n\n#{link[:markdown]}"
+          end.join
+        end
+
+        def validate_permission!(permission)
+          raise UserNotFoundError unless author
+          raise UserBlockedError if author.blocked?
+          raise ProjectNotFound unless author.can?(:read_project, project)
+          raise UserNotAuthorizedError unless author.can?(permission, project)
+        end
+
+        def verify_record!(record:, invalid_exception:, record_name:)
+          return if record.persisted?
+          return if record.errors.key?(:commands_only)
+
+          error_title = "The #{record_name} could not be created for the following reasons:"
+
+          msg = error_title + record.errors.full_messages.map do |error|
+            "\n\n- #{error}"
+          end.join
+
+          raise invalid_exception, msg
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/email/handler/unsubscribe_handler.rb b/lib/gitlab/email/handler/unsubscribe_handler.rb
new file mode 100644
index 00000000000..97d7a8d65ff
--- /dev/null
+++ b/lib/gitlab/email/handler/unsubscribe_handler.rb
@@ -0,0 +1,32 @@
+require 'gitlab/email/handler/base_handler'
+
+module Gitlab
+  module Email
+    module Handler
+      class UnsubscribeHandler < BaseHandler
+        def can_handle?
+          mail_key =~ /\A\w+#{Regexp.escape(Gitlab::IncomingEmail::UNSUBSCRIBE_SUFFIX)}\z/
+        end
+
+        def execute
+          raise SentNotificationNotFoundError unless sent_notification
+          return unless sent_notification.unsubscribable?
+
+          noteable = sent_notification.noteable
+          raise NoteableNotFoundError unless noteable
+          noteable.unsubscribe(sent_notification.recipient)
+        end
+
+        private
+
+        def sent_notification
+          @sent_notification ||= SentNotification.for(reply_key)
+        end
+
+        def reply_key
+          mail_key.sub(Gitlab::IncomingEmail::UNSUBSCRIBE_SUFFIX, '')
+        end
+      end
+    end
+  end
+end