Replica: Add message token for bounces

app/senders/smtp_sender.rb

@@ -142,10 +142,10 @@ def determine_mail_from_for_message(message)
     # If the domain has a valid custom return path configured, return
     # that.
     if message.domain.return_path_status == "OK"
-      return "#{message.server.token}@#{message.domain.return_path_domain}"
+      return "#{message.server.token}+#{message.token}@#{message.domain.return_path_domain}"
     end
 
-    "#{message.server.token}@#{Postal::Config.dns.return_path_domain}"
+    "#{message.server.token}+#{message.token}@#{Postal::Config.dns.return_path_domain}"
   end
 
   # Return the RCPT TO to use for the given message in this sending session

doc/config/yaml.yml

@@ -23,6 +23,8 @@ postal:
   use_local_ns_for_domain_verification: false
   # Append a Resend-Sender header to all outgoing e-mails
   use_resent_sender_header: true
+  # Use message tags when assigning bounces to their corresponding messages
+  use_message_tags_for_bounces: false
   # Path to the private key used for signing
   signing_key_path: $config-file-root/signing.key
   # An array of SMTP relays in the format of smtp://host:port

lib/postal/config_schema.rb

@@ -66,6 +66,11 @@ module Postal
         default true
       end
 
+      boolean :use_message_tags_for_bounces do
+        description "Use message tags when assigning bounces to their corresponding messages"
+        default false
+      end
+
       string :signing_key_path do
         description "Path to the private key used for signing"
         default "$config-file-root/signing.key"

lib/postal/message_db/message.rb

@@ -499,7 +499,17 @@ def create_link(url)
       def original_messages
         return nil unless bounce
 
-        other_message_ids = raw_message.scan(/\X-Postal-MsgID:\s*([a-z0-9]+)/i).flatten
+        # if this is enabled, we search first for the message tag as this is faster
+        # than to scan the full message (which is probably many mbytes in size)
+        if Postal::Config.postal.use_message_tags_for_bounces?
+          uname, domain = rcpt_to.split("@", 2)
+          uname, other_message_ids = uname.split("+", 2)
+        end
+        # if we did not found any messages, or this was not enabled, then fall back to
+        # the old header based search
+        if other_message_ids.nil? || other_message_ids.empty?
+          other_message_ids = raw_message.scan(/\X-Postal-MsgID:\s*([a-z0-9]+)/i).flatten
+        end
         if other_message_ids.empty?
           []
         else

spec/senders/smtp_sender_spec.rb

@@ -263,7 +263,7 @@
             sender.send_message(message)
             expect(sender.endpoints.last).to have_received(:send_message).with(
               kind_of(String),
-              "#{server.token}@#{domain.return_path_domain}",
+              "#{server.token}+#{message.token}@#{domain.return_path_domain}",
               ["[email protected]"]
             )
           end
@@ -274,7 +274,7 @@
             sender.send_message(message)
             expect(sender.endpoints.last).to have_received(:send_message).with(
               kind_of(String),
-              "#{server.token}@#{Postal::Config.dns.return_path_domain}",
+              "#{server.token}+#{message.token}@#{Postal::Config.dns.return_path_domain}",
               ["[email protected]"]
             )
           end
@@ -308,7 +308,7 @@
           it "adds the resent-sender header" do
             sender.send_message(message)
             expect(sender.endpoints.last).to have_received(:send_message).with(
-              "Resent-Sender: #{server.token}@#{Postal::Config.dns.return_path_domain}\r\n#{message.raw_message}",
+              "Resent-Sender: #{server.token}+#{message.token}@#{Postal::Config.dns.return_path_domain}\r\n#{message.raw_message}",
               kind_of(String),
               kind_of(Array)
             )