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E-Mail Handling and Processing

Slingshot Hosting Servers are by default setup to handle simple e-mail setups. If you're looking to have all the bells and whistles of a fully functioning e-mail server with POP3/IMAP/SMTP-AUTH, you may add this functionality to your server yourself (guide here), however, we recommend simply using a mail server for mail and a Rails application server for Rails applications. Below you'll find the simplest ways to handle mail, including forwarding and processing.

Simple Mail Handling
Incoming Mail Processing

Simple Mail Handling

To create a forward so that mail sent to your server is forwarded somewhere else, simply add a user and edit their .forward file.

daytona # useradd -m -G users -s /bin/bash bobjones
daytona # cd /home/bobjones
daytona # nano .forward

The forward file can simply list e-mail addresses that you'd like to forward to:

bobjones@gmail.com
bobby_jones29@hotmail.com

Incoming Mail Processing

First, ensure you're running either postfix or qmail. Skip down to the appropriate instructions for postfix below if you're using our newest image.

Forwarding mail to Rails ActionMailer with qmail

There are lots of ways to do it, but here’s an easy one.

First, ensure that normal mail delivery occurs.

Now, let’s create the user/email to be our action mailer address, for example the email ruby-mail@highgroove.com will pipe to our ruby runner:

daytona $ useradd -m -G users -s /bin/false ruby-mail

This adds a user with no abilities to login, just sets up a “home” directory for them.

You can view it at /home/ruby-mail

Next, let’s change the default deliver to a .maildir directory to pipe to our program. With qmail, we simply edit the .qmail file in the ruby-mail directory:

daytona $ vi /home/ruby-mail/.qmail

and put in one line:

| /usr/bin/ruby /path/to/app/script/runner

To test this you can use the following one-liner instead:

| /bin/cat > /tmp/test.txt

Which simply drops any email sent to ruby-mail@highgroove.com to a test.txt file in the tmp directory. So, as long as you’ve got the pipe correctly done and your ruby script is taking in the input from STDIN, you should be fine.

Since we do have procmail, another way is to change the .qmail to read:

| /usr/bin/procmail

And then we could add a .procmailrc file to /home/ruby-mail to do all kinds of procmail rules to deliver (like the Agile Web with Rails book has as an example—subject line matching etc.)

Alternatively we could even make the .procmailrc part of the code for the web app if it got kind of hairy and then setup a symlink to it:

| /usr/bin/procmail /path/to/app/config/procmail_rules

Forwarding mail to Rails ActionMailer with Postfix

The easiest way to forward mail from postifix is to setup a new alias.

First, create an alias on the machine, for example: "rails-mail" and add it like to your aliases file located in /etc/aliases

rails-mail: "|/path/to/app/script/runner 'Mailman.receive(STDIN.read)'"

Any time you update the aliases file, you must run the command: newalises.

newaliases

If you are using virtual hosts in Postfix, you need to inform Postfix that incoming emails of a given address should be forwarded to this alias by adding a line below to /etc/postfix/virtual:

/^.*@.*example.com$/          rails-mail

Changes to this file require a postfix restart (and possible a recompile of the configuration file). While in /etc/postfix run this to recompile the settings manually:

make && make install

Your ActionMailer should work now. To test, you can simply setup a handler that outputs to a file. In your aliases file, put the line:

rails-mail: "|cat /tmp/incoming_mail.txt"

All your incoming mail will now be put into a file /tmp/incoming_mail.txt for testing purposes