james-listmanager-proposal.txt

邮件服务器系统 支持SMTP POP3 是著名的Apache写 有一定的参考价值

Proposal:
    To add a pluggable command-based list serv manager to the James Mail Server project.

Quick Note:
    I leveraged the code and structure of the default list serv manager, but didn't extend that code.
    I however want to acknowledge the developer of that code as providing a very nice reference implementation.

Features:
    A list serv manager that can be configured to accept plugin commands handlers.
    Text-based resources that allow standard list serv mail responses to be customized without recompilation.
    2 stage subscription and unsubscription
    An implementation of some standard listserv commands including:
        subscribe
        subscribe-confirm
        unsubscribe
        unsubscribe-confirm
        error
        info
    An opprotunity to provide user-friendly welcome/goodbye/info list serv responses.


Architecture:
    The functionality is divided into three main parts:
        CommandListServManager: Responsible for creating and delegating to the list serv commands
        ListServCommands: A collection of plugins that handle specific commands like "info".
        CommandListservProcessor: processes mail sent to the list serv for general 'broadcasting'.

    CommandListServManager:
        At initialization time, the CommandListServManager will load list serv specific config info like: listName,
        listOwner, etc... It also loads and initializes all the available plugin commands.
        At runtime, the CommandListServManager determines if it has a registered command for the request.
        If so, it delegates to that command handler, if not, it sends an error using the ErrorCommand command handler.

    ListServCommands:
        All list serv commands implement the IListServCommand interface.  They typically perform any required business
        logic, and then send reply mail.  All reply mail is typically based upon the text based resources.  These
        text based resources, in theory, allow the list administrator to customize the messages sent to the mail list
        without recompilation.

   CommandListservProcessor:
        When mail is sent to the processor, standard checks are made (like whether the user is a current member, and
        if not, if they can still send email to the list...).  Then the subject line is formatted, some headers are
        set to prevent permenent bouncing, and a footer is added which includes unsubscribe and info links.


Todo:
    Handle more complex mail commands:
        Should handle mail addresses with the format: <listName>-<commandName>-<optionalCommandParams>@domain
        This allows for more complex commands like: retrieve messages from start range to end range.
    Confirmation commands:
        Are easily spoofed due to the lack of 'command params' specified above.
    MessageDigest:
        Being relatively new to James, i'm not sure how or where to store extra user metadata like
        subscription type (normal|digest).  Once this was in place, then i would need to register a schedule with
        Avalon, and ensure that i had a persistent data store of the mail messages.  (This could be done with a private
        list subscriber).



Disclaimer:
    I've tried to maintain both the coding standards and spirit of the current James dist (2.1) (not 2.1.1) as
    much as possible.  With that said, i'm sure careful examination will show not only mistakes, but also superior
    methods for implementing the same features.


--Mark Imel
February 16, 2003
[e-mail]