rusmes-imap

IMAP protocol implementation for RusMES, targeting RFC 9051 (IMAP4rev2) compliance.

Status

Foundation is in place: command types, parser skeleton, session state machine, response builder, and server skeleton. The full IMAP command set needs implementation.

Architecture

ImapServer
  |-- accepts TCP connections (143 / 993)
  |-- spawns ImapSession per connection
  |     |-- ImapState machine
  |     |-- Command parser (nom-based)
  |     |-- Response builder (tagged/untagged)
  |     |-- Authentication (via rusmes-auth)
  |     '-- Mailbox access (via rusmes-storage)
  '-- TLS support via rustls

Modules

Module	Description
`server`	`ImapServer` - TCP listener and connection dispatch
`session`	`ImapSession` - per-connection state machine
`command`	`ImapCommand` enum - IMAP command types
`parser`	IMAP command parser (nom-based)
`response`	`ImapResponse` builder for tagged and untagged responses

Session States (RFC 9051)

Not Authenticated
  |-- LOGIN / AUTHENTICATE -> Authenticated
  |-- STARTTLS -> Not Authenticated (upgraded)
  '-- LOGOUT -> Logout

Authenticated
  |-- SELECT / EXAMINE -> Selected
  |-- CREATE / DELETE / RENAME / LIST / SUBSCRIBE
  '-- LOGOUT -> Logout

Selected
  |-- FETCH / STORE / SEARCH / EXPUNGE / COPY / MOVE
  |-- CLOSE -> Authenticated
  |-- SELECT -> Selected (different mailbox)
  '-- IDLE (push notifications)

Dependencies

rusmes-proto - mail types
rusmes-storage - mailbox and message storage
rusmes-auth - authentication
nom - command parsing
rustls / tokio-rustls - TLS
tokio - async networking

Tests

cargo test -p rusmes-imap   # foundation tests