FEATURE: new 'ignore_by_title' site setting

config/locales/server.en.yml

@@ -1178,6 +1178,7 @@ en:
     auto_generated_whitelist: "List of email addresses that won't be checked for auto-generated content."
     block_auto_generated_emails: "Block incoming emails identified as being auto generated."
     bounce_score_threshold: "Max score before we will stop emailing a user. Soft bounce adds 1, hard bounce adds 2, score reset 30 days after last bounce."
+    ignore_by_title: "Ignore incoming emails based on their title."
 
     manual_polling_enabled: "Push emails using the API for email replies."
     pop3_polling_enabled: "Poll via POP3 for email replies."

config/site_settings.yml

@@ -576,6 +576,9 @@ email:
     client: true
     default: 4
     min: 1
+  ignore_by_title:
+    type: list
+    default: ''
 
 
 files:

lib/email/receiver.rb

@@ -38,14 +38,20 @@ module Email
     end
 
     def process!
+      return if is_blacklisted?
       @from_email, @from_display_name = parse_from_field
       @incoming_email = find_or_create_incoming_email
       process_internal
     rescue => e
-      @incoming_email.update_columns(error: e.to_s)
+      @incoming_email.update_columns(error: e.to_s) if @incoming_email
       raise
     end
 
+    def is_blacklisted?
+      return false if SiteSetting.ignore_by_title.blank?
+      Regexp.new(SiteSetting.ignore_by_title) =~ @mail.subject
+    end
+
     def find_or_create_incoming_email
       IncomingEmail.find_or_create_by(message_id: @message_id) do |ie|
         ie.raw = @raw_email

spec/components/email/receiver_spec.rb

@@ -407,6 +407,11 @@ describe Email::Receiver do
       expect { process(:tl4_user) }.to change(Topic, :count)
     end
 
+    it "ignores by title" do
+      SiteSetting.ignore_by_title = "foo"
+      expect { process(:ignored) }.to_not change(Topic, :count)
+    end
+
   end
 
 end

spec/fixtures/emails/ignored.eml

@@ -0,0 +1,11 @@
+Return-Path: <foo@bar.com>
+From: Foo Bar <foo@bar.com>
+To: category@foo.com
+Subject: This is a foo topic
+Date: Fri, 15 Jan 2016 00:12:43 +0100
+Message-ID: <53@foo.bar.mail>
+Mime-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: quoted-printable
+
+Hey, this is an incoming email that will be ignored ;)