# Membership changes via email

Membership changes such as joining and leaving a mailing list, can be effected via the email interface. The Mailman email commands `join`, `leave`, and `confirm` are used.

## Joining a mailing list

The mail command `join` subscribes an email address to the mailing list. `subscribe` is an alias for `join`.

    >>> from mailman.commands.eml_membership import Join
    >>> from mailman.utilities.string import wrap
    >>> join = Join()
    >>> print(join.name)
    join
    >>> print(wrap(join.description))
    You will be asked to confirm your subscription request and you may be
    issued a provisional password.

    By using the 'digest' option, you can specify whether you want digest
    delivery or not.  If not specified, the mailing list's default
    delivery mode will be used.
    >>> print(join.argument_description)
    [digest=<no|mime|plain>]

### No address to join

    >>> mlist = create_list('alpha@example.com')
    >>> mlist.send_welcome_message = False

When no address argument is given, the message’s From address will be used. If that’s missing though, then an error is returned.

    >>> from mailman.runners.command import Results
    >>> results = Results()

    >>> from mailman.email.message import Message
    >>> print(join.process(mlist, Message(), {}, (), results))
    ContinueProcessing.no
    >>> print(results)
    The results of your email command are provided below.

    join: No valid address found to subscribe

The `subscribe` command is an alias.

    >>> from mailman.commands.eml_membership import Subscribe
    >>> subscribe = Subscribe()
    >>> print(subscribe.name)
    subscribe
    >>> results = Results()
    >>> print(subscribe.process(mlist, Message(), {}, (), results))
    ContinueProcessing.no
    >>> print(results)
    The results of your email command are provided below.

    subscribe: No valid address found to subscribe

### Joining the sender

When the message has a `From` field, that address will be subscribed.

    >>> msg = message_from_string("""\
    ... From: Anne Person <anne@example.com>
    ...
    ... """)
    >>> results = Results()
    >>> print(join.process(mlist, msg, {}, (), results))
    ContinueProcessing.yes
    >>> print(results)
    The results of your email command are provided below.

    Confirmation email sent to Anne Person <anne@example.com>

Anne is not yet a member of the mailing list because she must confirm her subscription request first.

    >>> print(mlist.members.get_member('anne@example.com'))
    None

Mailman has sent her the confirmation message.

    >>> from mailman.testing.helpers import get_queue_messages
    >>> items = get_queue_messages('virgin')
    >>> len(items)
    1
    >>> print(items[0].msg.as_string())
    MIME-Version: 1.0
    ...
    Subject: confirm ...
    From: alpha-confirm+...@example.com
    To: anne@example.com
    ...

    Email Address Registration Confirmation

    Hello, this is the GNU Mailman server at example.com.

    We have received a registration request for the email address

        anne@example.com

    Before you can start using GNU Mailman at this site, you must first confirm
    that this is your email address.  You can do this by replying to this me...
    keeping the Subject header intact.

    If you do not wish to register this email address, simply disregard this
    message.  If you think you are being maliciously subscribed to the list, or
    have any other questions, you may contact

        alpha-owner@example.com

Anne confirms her registration.

    >>> def extract_token(message):
    ...     return str(message['subject']).split()[1].strip()
    >>> token = extract_token(items[0].msg)

    >>> from mailman.commands.eml_confirm import Confirm
    >>> confirm = Confirm()
    >>> msg = message_from_string("""\
    ... To: alpha-confirm+{token}@example.com
    ... From: anne@example.com
    ... Subject: Re: confirm {token}
    ...
    ... """.format(token=token))

    >>> results = Results()
    >>> print(confirm.process(mlist, msg, {}, (token,), results))
    ContinueProcessing.yes
    >>> print(results)
    The results of your email command are provided below.

    Confirmed

Anne is now a member of the mailing list.

    >>> mlist.members.get_member('anne@example.com')
    <Member: Anne Person <anne@example.com>
             on alpha@example.com as MemberRole.member>

### Joining a second list

    >>> mlist_2 = create_list('baker@example.com')
    >>> msg = message_from_string("""\
    ... From: Anne Person <anne@example.com>
    ...
    ... """)
    >>> print(join.process(mlist_2, msg, {}, (), Results()))
    ContinueProcessing.yes

Anne is not a member of the mailing list.

    >>> print(mlist_2.members.get_member('anne@example.com'))
    None

One Anne confirms this subscription, she becomes a member of the mailing list.

    >>> items = get_queue_messages('virgin')
    >>> len(items)
    1
    >>> token = extract_token(items[0].msg)
    >>> msg = message_from_string("""\
    ... To: baker-confirm+{token}@example.com
    ... From: anne@example.com
    ... Subject: Re: confirm {token}
    ...
    ... """.format(token=token))

    >>> results = Results()
    >>> print(confirm.process(mlist_2, msg, {}, (token,), results))
    ContinueProcessing.yes
    >>> print(results)
    The results of your email command are provided below.

    Confirmed

    >>> print(mlist_2.members.get_member('anne@example.com'))
    <Member: Anne Person <anne@example.com>
             on baker@example.com as MemberRole.member>

## Leaving a mailing list

The mail command `leave` unsubscribes an email address from the mailing list. `unsubscribe` is an alias for `leave`.

    >>> from mailman.commands.eml_membership import Leave
    >>> leave = Leave()
    >>> print(leave.name)
    leave
    >>> print(leave.description)
    Leave this mailing list.

    You may be asked to confirm your request.

Anne is a member of the `baker@example.com` mailing list, when she decides to leave it. Because the mailing list allows for open unsubscriptions (i.e. no confirmation is needed), when she sends a message to the `-leave` address for the list, she is immediately removed.

    >>> from mailman.interfaces.mailinglist import SubscriptionPolicy
    >>> mlist_2.unsubscription_policy = SubscriptionPolicy.open
    >>> mlist.unsubscription_policy = SubscriptionPolicy.open
    >>> results = Results()
    >>> print(leave.process(mlist_2, msg, {}, (), results))
    ContinueProcessing.yes
    >>> print(results)
    The results of your email command are provided below.

    Anne Person <anne@example.com> left baker@example.com

Anne is no longer a member of the mailing list.

    >>> print(mlist_2.members.get_member('anne@example.com'))
    None

Anne does not need to leave a mailing list with the same email address she’s subscribe with. Any of her registered, linked, and validated email addresses will do.

    >>> from mailman.interfaces.usermanager import IUserManager
    >>> from zope.component import getUtility
    >>> anne = getUtility(IUserManager).get_user('anne@example.com')
    >>> address = anne.register('anne.person@example.org')

    >>> results = Results()
    >>> print(mlist.members.get_member('anne@example.com'))
    <Member: Anne Person <anne@example.com>
             on alpha@example.com as MemberRole.member>

    >>> msg = message_from_string("""\
    ... To: alpha-leave@example.com
    ... From: anne.person@example.org
    ...
    ... """)

Since Anne’s alternative address has not yet been verified, it can’t be used to unsubscribe Anne from the alpha mailing list.

    >>> print(leave.process(mlist, msg, {}, (), results))
    ContinueProcessing.no

    >>> print(results)
    The results of your email command are provided below.

    Invalid or unverified email address: anne.person@example.org

    >>> print(mlist.members.get_member('anne@example.com'))
    <Member: Anne Person <anne@example.com>
             on alpha@example.com as MemberRole.member>

Once Anne has verified her alternative address though, it can be used to unsubscribe her from the list.

    >>> from mailman.utilities.datetime import now
    >>> address.verified_on = now()

    >>> results = Results()
    >>> print(leave.process(mlist, msg, {}, (), results))
    ContinueProcessing.yes

    >>> print(results)
    The results of your email command are provided below.

    Anne Person <anne.person@example.org> left alpha@example.com

    >>> print(mlist.members.get_member('anne@example.com'))
    None

## Confirmations

Bart wants to join the alpha list, so he sends his subscription request.

    >>> msg = message_from_string("""\
    ... From: Bart Person <bart@example.com>
    ...
    ... """)

    >>> print(join.process(mlist, msg, {}, (), Results()))
    ContinueProcessing.yes

There are two messages in the virgin queue, one of which is the confirmation message.

    >>> for item in get_queue_messages('virgin'):
    ...     if str(item.msg['subject']).startswith('confirm'):
    ...         break
    ... else:
    ...     raise AssertionError('No confirmation message')
    >>> token = extract_token(item.msg)

Bart replies to the original message, specifically keeping the Subject header intact except for any prefix. Mailman matches the token and confirms Bart as a user of the system.

    >>> msg = message_from_string("""\
    ... From: Bart Person <bart@example.com>
    ... To: alpha-confirm+{token}@example.com
    ... Subject: Re: confirm {token}
    ...
    ... """.format(token=token))

    >>> results = Results()
    >>> print(confirm.process(mlist, msg, {}, (token,), results))
    ContinueProcessing.yes

    >>> print(results)
    The results of your email command are provided below.

    Confirmed

Now Bart is now a member of the mailing list.

    >>> print(mlist.members.get_member('bart@example.com'))
    <Member: Bart Person <bart@example.com>
             on alpha@example.com as MemberRole.member>