BackendMailboxAPI

Backend Mailbox API Feature Requirements

• This list of features we need to support, or want to support by the backend API.

• POP3 needs

  • 'username+password' -> 'inbox' mapping,

  • listing of the content of inbox, with subject only (?)

  • getting the content of an email by it's id

  • deleting messages from the inbox

• SMTP needs

  • 'email address' -> 'mailbox' mapping

  • putting an email into the mailbox

  • SMTP compliance we should make sure that a message is not normalized or "fixed" before it is relayed

• NNTP needs

  • ???? I don't know

• Internal James API needs (spooling, fetchmail, etc):

  • handling various 'spool' 'mailbox'es, adding and removing items to them.

• IMAP needs:

  • handle mail specific flags (Answered, Deleted, Draft, Flagged, Recent, Seen...)

  • ability to search by various header parameters (From, Subject...), flags

  • handle mailbox hierarchy per user (this would be nice for JSieve also, as I know)

  • shared/readonly mailboxes (this is optional)

  • custom properties for mail, the MIME structure is important, but some useful imap extensions needs others, for example CONDSTORE/QRESYNC as I remember needs a 'transaction number'.

• Other features, which we want to consider comes from the deployment scenarios :

  • db only backend

  • db for the metadata, file system for the data, in maildir/mbox/custom format

  • db less backend, pure file system

  • mixed backend (for example, the user mailbox are in a db, the shared, read only mailboxes are on the disk.

  • jcr backend

  • james servers in front of the same backend (probably db-only, or jcr)

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Current API

Here's a class diagram for the current interfaces:

Seems excessively complex

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MIME Structure Strawman

Here's a strawman for MIME Structure:

Probably something simple should be enough - some recursion, a couple of interfaces plus access to mail headers, MIME meta-data and Content should be enough.

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Factories, Factories and more Factories

Here's a class diagram for the current factory interfaces which create managers and mailboxes:

Again, seems excessively complex. IMHO it would be better to have a canonical mechanism for each function. Concise APIs are easier to learn and easier to implement.