Saving emails

[EtienneBruines]

According to #29 I've implemented a way for our server to receive incoming emails from Postfix (SMTP server), using the LMTP protocol. This means we can serve actual emails to end-users.

What we receive from Postfix:

• The sender (e-mail address)
• The recipients (plural, and we can process them individually); meaning we can:
  • deny it for user A because we don't know him;
  • accept it for user B because we like him;
  • deny it for user C because his quota is reached;
  • accept it for user D because we like him too;
  • ... and the MTA (SMTP server) will be OK with that.
• Raw message, i.e.:

Received: from there (localhost [IPv6:::1])
        by receiver.local (Postfix) with SMTP id EE9EB416D4
        for <postmaster@receiver.local>; Mon, 29 Jun 2015 15:35:31 +0200 (CEST)
Message-Id: <20150629133541.EE9EB416D4@receiver.local>
Date: Mon, 29 Jun 2015 15:35:31 +0200 (CEST)
From: hello@sender.local

hi there

We should probably have an interface that stores this information, so anyone can implement it any way they like. The message should go inside the "mailboxes" of the recipients, so we can eventually serve them to the end-users. Should we do any preprocessing? (such as timestamp, name of sender, name of receiver, optional subject, etc.) -- and if so, which attributes?

Or do we simply store the raw data somewhere?

Thoughts? @alienscience @waffle-iron (or anyone for that matter?)

[alienscience]

The raw data should be saved - probably by calling the Mailstore which can then write it to a database or file system.

The message should have a 32bit IMAP uid assigned to it and also flags:

// Message flags
const (
    // The message has been read
    Seen = 1 << iota
    // The message has been answered
    Answered
    // The message has been flagged for urgent/special attention
    Flagged
    // The message has been marked for removal by EXPUNGE
    Deleted
    // The message is imcomplete and is being worked on
    Draft
    // The message has recently arrived in the mailbox
    Recent
)

var messageFlags = map[uint8]string{
    Seen:     `\Seen`,
    Answered: `\Answered`,
    Flagged:  `\Flagged`,
    Deleted:  `\Deleted`,
    Draft:    `\Draft`,
    Recent:   `\Recent`,
}