herolib/lib/servers/mail/imap

IMAP Server

A simple IMAP server implementation in V that supports basic mailbox operations.

Features

• IMAP server implementation with persistent storage via mailbox module
• Support for multiple mailboxes
• Basic IMAP commands: LOGIN, SELECT, FETCH, STORE, LOGOUT
• Message flags support (e.g. \Seen, \Flagged)
• Concurrent client handling

Usage

The server can be started with a simple function call:

import freeflowuniverse.herolib.servers.imap

fn main() {
    // Start the IMAP server on port 143
    imap.start() or { panic(err) }
}

Save this to example.v and run with:

v run example.v

The server will start listening on port 143 (default IMAP port) and initialize with an example INBOX containing two messages.

Testing with an IMAP Client

You can test the server using any IMAP client. Here's an example using the curl command:

# Connect and login (any username/password is accepted)
curl "imap://localhost/" -u "user:pass" --ssl-reqd

# List messages in INBOX
curl "imap://localhost/INBOX" -u "user:pass" --ssl-reqd

Implementation Details

The server consists of three main components:

1. Model (model.v): Defines the core data structures

   • Uses the mailbox module for message storage and retrieval
   • Handles mailbox operations through a standardized interface
   • Provides message and mailbox management functionality

2. Server (server.v): Handles the IMAP protocol implementation

   • TCP connection handling
   • IMAP command processing
   • Concurrent client support

3. Factory (factory.v): Provides easy server initialization

   • start() function to create and run the server
   • Initializes example INBOX with sample messages
   • Sets up mailbox storage backend

Supported Commands

• CAPABILITY: List server capabilities
• LOGIN: Authenticate (accepts any credentials)
• SELECT: Select a mailbox
• FETCH: Retrieve message data
• STORE: Update message flags
• LOGOUT: End the session

Example Session

C: A001 CAPABILITY
S: * CAPABILITY IMAP4rev1 AUTH=PLAIN
S: A001 OK CAPABILITY completed

C: A002 LOGIN user pass
S: A002 OK LOGIN completed

C: A003 SELECT INBOX
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * 2 EXISTS
S: A003 OK SELECT completed

C: A004 FETCH 1:* BODY[TEXT]
S: * 1 FETCH (FLAGS (\Seen) BODY[TEXT] "Welcome to the IMAP server!")
S: * 2 FETCH (FLAGS () BODY[TEXT] "This is an update.")
S: A004 OK FETCH completed

C: A005 STORE 2 +FLAGS (\Seen)
S: A005 OK STORE completed

C: A006 CAPABILITY
S: * CAPABILITY IMAP4rev1 AUTH=PLAIN
S: A006 OK CAPABILITY completed

C: A007 LOGOUT
S: * BYE IMAP4rev1 Server logging out
S: A007 OK LOGOUT completed

Notes

• The server runs on port 143, which typically requires root privileges. Make sure you have the necessary permissions.
• This is a basic implementation for demonstration purposes. For production use, consider adding:
  • Proper authentication
  • Full IMAP command support
  • TLS encryption
  • Message parsing and MIME support