Fixed issue #731 - Do not import own notification emails in Zammad.

app/models/channel/filter/own_notification_loop_detection.rb

@@ -0,0 +1,20 @@
+# Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/
+
+module Channel::Filter::OwnNotificationLoopDetection
+
+  def self.run(_channel, mail)
+
+    message_id = mail['message-id'.to_sym]
+    return if !message_id
+    recedence = mail['precedence'.to_sym]
+    return if !recedence
+    return if recedence !~ /bulk/i
+
+    fqdn = Setting.get('fqdn')
+    return if message_id !~ /@#{Regexp.quote(fqdn)}>/i
+
+    mail[ 'x-zammad-ignore'.to_sym ] = true
+    Rails.logger.info "Detected onw sent notification mail and dropped it to prevent loops (message_id: #{message_id}, from: #{mail[:from]}, to: #{mail[:to]})"
+
+  end
+end

app/models/transaction/notification.rb

@@ -206,6 +206,7 @@ class Transaction::Notification
           current_user: current_user,
           changes: changes,
         },
+        message_id: "<notification.#{DateTime.current.to_s(:number)}.#{ticket.id}.#{user.id}.#{rand(999_999)}@#{Setting.get('fqdn')}>",
         references: ticket.get_references,
         main_object: ticket,
         attachments: attachments,

db/migrate/20170203000003_do_not_import_onw_notifications_731.rb

@@ -0,0 +1,18 @@
+class DoNotImportOnwNotifications731 < ActiveRecord::Migration
+  def up
+
+    # return if it's a new setup
+    return if !Setting.find_by(name: 'system_init_done')
+
+    Setting.create_if_not_exists(
+      title: 'Define postmaster filter.',
+      name: '0014_postmaster_filter_own_notification_loop_detection',
+      area: 'Postmaster::PreFilter',
+      description: 'Define postmaster filter to check if email is a own created notification email, then ignore it to prevent email loops.',
+      options: {},
+      state: 'Channel::Filter::OwnNotificationLoopDetection',
+      frontend: false
+    )
+
+  end
+end

db/seeds.rb

@@ -2200,6 +2200,15 @@ Setting.create_if_not_exists(
   state: 'Channel::Filter::SenderIsSystemAddress',
   frontend: false
 )
+Setting.create_if_not_exists(
+  title: 'Defines postmaster filter.',
+  name: '0014_postmaster_filter_own_notification_loop_detection',
+  area: 'Postmaster::PreFilter',
+  description: 'Define postmaster filter to check if email is a own created notification email, then ignore it to prevent email loops.',
+  options: {},
+  state: 'Channel::Filter::OwnNotificationLoopDetection',
+  frontend: false
+)
 Setting.create_if_not_exists(
   title: 'Defines postmaster filter.',
   name: '0015_postmaster_filter_identify_sender',

lib/notification_factory/mailer.rb

@@ -90,7 +90,8 @@ returns
     subject:      'sime subject',
     body:         'some body',
     content_type: '', # optional, e. g. 'text/html'
-    references:   ['message-id123', 'message-id456'],
+    message_id: '<some_message_id@fqdn>', # optional
+    references:   ['message-id123', 'message-id456'], # optional
     attachments:  [attachments...], # optional
   )
 
@@ -113,6 +114,7 @@ returns
         from: sender,
         to: data[:recipient][:email],
         subject: data[:subject],
+        message_id: data[:message_id],
         references: data[:references],
         body: data[:body],
         content_type: content_type,
@@ -131,7 +133,8 @@ returns
       recipient: User.find(2),
     },
     main_object: ticket.find(123), # optional
-    references: ['message-id123', 'message-id456'],
+    message_id: '<some_message_id@fqdn>', # optional
+    references: ['message-id123', 'message-id456'], # optional
     standalone: true, # default: false - will send header & footer
     attachments: [attachments...], # optional
   )
@@ -158,6 +161,7 @@ returns
       subject: result[:subject],
       body: result[:body],
       content_type: 'text/html',
+      message_id: data[:message_id],
       references: data[:references],
       attachments: data[:attachments],
     )

test/unit/email_process_test.rb

@@ -18,6 +18,34 @@ Some Text',
         },
         success: true,
       },
+      {
+        data: "From: my_own_zammad@example.com
+To: customer_which_is_routed_into_my_zammad@example.com
+Subject: some subject
+Message-ID: <1234@#{Setting.get('fqdn')}>
+
+Some Text",
+        channel: {
+          trusted: false,
+        },
+        success: true,
+      },
+      {
+        data: "From: my_own_zammad@example.com
+To: customer_which_is_routed_into_my_zammad@example.com
+Subject: some subject
+Message-ID: <1234@#{Setting.get('fqdn')}>
+X-Loop: yes
+Precedence: bulk
+Auto-Submitted: auto-generated
+X-Auto-Response-Suppress: All
+
+Some Text",
+        channel: {
+          trusted: false,
+        },
+        success: false,
+      },
       {
         data: "From: me@example.com
 To: customer@example.com