Moderation

Posts by members and nonmembers are subject to moderation checks during incoming processing. Different situations can cause such posts to be held for moderator approval.

>>> mlist = create_list('test@example.com')

Members and nonmembers have a moderation action which can shortcut the normal moderation checks. The built-in chain does just a few checks first, such as seeing if the message has a matching Approved: header, or if the emergency flag has been set on the mailing list, or whether a mail loop has been detected.

After those, the moderation action for the sender is checked. Members generally have a defer action, meaning the normal moderation checks are done, but it is also common for first-time posters to have a hold action, meaning that their messages are held for moderator approval for a while.

Nonmembers almost always have a hold action, though some mailing lists may choose to set this default action to discard, meaning their posts would be immediately thrown away.

Member moderation

Posts by list members are moderated if the member’s moderation action is not deferred. The default setting for the moderation action of new members is determined by the mailing list’s settings. By default, a mailing list is not set to moderate new member postings.

>>> from mailman.testing.helpers import subscribe
>>> member = subscribe(mlist, 'Anne', email='anne@example.com')
>>> member
<Member: Anne Person <anne@example.com> on test@example.com
         as MemberRole.member>
>>> print(member.moderation_action)
Action.defer

In order to find out whether the message is held or accepted, we can subscribe to Zope events that are triggered on each case.

>>> from mailman.interfaces.chain import ChainEvent
>>> def on_chain(event):
...     if isinstance(event, ChainEvent):
...         print(event)
...         print(event.chain)
...         print('Subject:', event.msg['subject'])
...         print('Hits:')
...         for hit in event.msgdata.get('rule_hits', []):
...             print('   ', hit)
...         print('Misses:')
...         for miss in event.msgdata.get('rule_misses', []):
...             print('   ', miss)

Anne’s post to the mailing list runs through the incoming runner’s default built-in chain. No rules hit and so the message is accepted.

>>> msg = message_from_string("""\
... From: anne@example.com
... To: test@example.com
... Subject: aardvark
...
... This is a test.
... """)

>>> from mailman.core.chains import process
>>> from mailman.testing.helpers import event_subscribers
>>> with event_subscribers(on_chain):
...     process(mlist, msg, {}, 'default-posting-chain')
<mailman.interfaces.chain.AcceptEvent ...>
<mailman.chains.accept.AcceptChain ...>
Subject: aardvark
Hits:
Misses:
    approved
    emergency
    loop
    member-moderation
    administrivia
    implicit-dest
    max-recipients
    max-size
    news-moderation
    no-subject
    suspicious-header
    nonmember-moderation

However, when Anne’s moderation action is set to hold, her post is held for moderator approval.

>>> from mailman.interfaces.action import Action
>>> member.moderation_action = Action.hold

>>> msg = message_from_string("""\
... From: anne@example.com
... To: test@example.com
... Subject: badger
...
... This is a test.
... """)

>>> with event_subscribers(on_chain):
...     process(mlist, msg, {}, 'default-posting-chain')
<mailman.interfaces.chain.HoldEvent ...>
<mailman.chains.hold.HoldChain ...>
Subject: badger
Hits:
    member-moderation
Misses:
    approved
    emergency
    loop

The list’s member moderation action can also be set to discard...

>>> member.moderation_action = Action.discard

>>> msg = message_from_string("""\
... From: anne@example.com
... To: test@example.com
... Subject: cougar
...
... This is a test.
... """)

>>> with event_subscribers(on_chain):
...     process(mlist, msg, {}, 'default-posting-chain')
<mailman.interfaces.chain.DiscardEvent ...>
<mailman.chains.discard.DiscardChain ...>
Subject: cougar
Hits:
    member-moderation
Misses:
    approved
    emergency
    loop

... or reject.

>>> member.moderation_action = Action.reject
>>> msg = message_from_string("""\
... From: anne@example.com
... To: test@example.com
... Subject: dingo
...
... This is a test.
... """)
>>> with event_subscribers(on_chain):
...     process(mlist, msg, {}, 'default-posting-chain')
<mailman.interfaces.chain.RejectEvent ...>
<mailman.chains.reject.RejectChain ...>
Subject: dingo
Hits:
    member-moderation
Misses:
    approved
    emergency
    loop

Nonmembers

Registered nonmembers are handled very similarly to members, the main difference being that they usually have a default moderation action. This is how the incoming runner adds sender addresses as nonmembers.

>>> from zope.component import getUtility
>>> from mailman.interfaces.usermanager import IUserManager
>>> user_manager = getUtility(IUserManager)
>>> address = user_manager.create_address('bart@example.com')
>>> address
<Address: bart@example.com [not verified] at ...>

When the moderation rule runs on a message from this sender, this address will be registered as a nonmember of the mailing list, and it will be held for moderator approval.

>>> msg = message_from_string("""\
... From: bart@example.com
... To: test@example.com
... Subject: elephant
...
... """)

>>> with event_subscribers(on_chain):
...     process(mlist, msg, {}, 'default-posting-chain')
<mailman.interfaces.chain.HoldEvent ...>
<mailman.chains.hold.HoldChain ...>
Subject: elephant
Hits:
    nonmember-moderation
Misses:
    approved
    emergency
    loop
    member-moderation
    administrivia
    implicit-dest
    max-recipients
    max-size
    news-moderation
    no-subject
    suspicious-header

>>> nonmember = mlist.nonmembers.get_member('bart@example.com')
>>> nonmember
<Member: bart@example.com on test@example.com as MemberRole.nonmember>
>>> print(nonmember.moderation_action)
Action.hold