This script serves as an example of how you can use the RFilter::DeliveryAgent class to perform mail delivery. You can also use this script as a fully functioning mail filter.
This script is a basic mail local delivery agent (DeliveryAgent) that can be used in place of procmail, maildrop, etc. in a user's .forward or .qmail file. The user supplies a delivery script that is written in Ruby, which avoids the limitations of the crippled mini-languages so often used in other DeliveryAgent programs.
rdeliver is invoked from the command line using:
% rdeliver <options> [script]
The script argument is optional. If omitted the script will look for a file called .rdeliver in the home directory.
The delivery script runs in the context of a class called Deliver (in contrast, most ruby scripts run in the context of the Object class). So any methods added with def will be added to the Deliver class.
A minimal delivery script would be:
def main agent.save('inbox') end
This code defines a Deliver#main method that saves the mail into an mbox style mailbox.
The only API the Deliver script has is the #agent method. This retrieves the RFilter::DeliveryAgent object associated with the current message. Using the API of the RFilter::DeliveryAgent object, you can access and modify the message body and headers, defer or reject the message delivery, and deliver into various mailbox formats.
Assuming you have the RubyMail mail classes installed, you typically have to put something like this in your .forward file:
|"/usr/local/bin/rdeliver --log /home/you/.rlog"
This will call rdeliver for each new message you get, and log to /home/you/.rlog.
The rdeliver script is very careful with errors. If there is any problem, it logs the error to the log file you specify. But if you do not specify a log file, or the error occurs before the log file is opened, a record of the error is placed in a file called CATASTROPHIC_DELIVERY_FAILURE in the home directory. If that fails, the error information is printed to the standard output in the hopes that it will be part of a bounce message. In all cases, the exit code 75 is returned, which tells the MTA to re-try the delivery again.