Action Mailbox - way to manually feed email

[Warren Prince]

Is there a way to process an email by manually copying/piping/catting an email without the use of an MTA ?  For example, assume I have a directory of email already received through my MTA (postfix in my case) and I want to process those email messages through ActionMailbox.  I'd like to do something like 

cat ~/jeff.eml | bin/rails action_mailbox:ingress:postfix URL=http://whp.myurl.com/rails/action_mailbox/relay/inbound_emails INGRESS_PASSWORD='???????????'

That results in an error 

No template found for ActionMailbox::Ingresses::Relay::InboundEmailsController#create, rendering head :no_content

I have a catch-all route pointed at archive_mailbox that works fine with email forwarded by postfix, but the manual email never reaches that mailbox.  From the log, I can tell that it does see the message_id as the last thing it does is insert into action_mailbox_inbound_emails which is then rolled back.  A log entry at the beginning of archive_mailbox never appears in the log.

I'd appreciate any ideas.  Thx.