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4.18 How message moderation works

ezmlm-store(1), invoked in DIR/editor, receives messages for message moderated lists. If DIR/modpost does not exist, ezmlm-store(1) just calls ezmlm-send(1) and the message is posted to the list as if it were not moderated. If DIR/modpost exists, ezmlm-store(1) places the message in DIR/mod/pending/. It also sends a moderation request to all the moderators. Included with this request is a copy of the message. The ‘From:’ and ‘Reply-To:’ email addresses contain codes for ‘reject’ and ‘accept’, together with a unique message name (derived from the message timestamp and process id) and a cookie based on these items. When a moderator replies, ezmlm-moderate(1) is invoked via DIR/moderator. ezmlm-moderate(1) validates the request, and if the request is valid and the message is found in DIR/mod/pending/, it carries out the requested action.

If the request is ‘reject’ the post is returned to SENDER with an explanation and an optional moderator comment. If the request is ‘accept’ the message is posted to the list via ezmlm-send(1). As the request is processed, a stub for the message is created in DIR/mod/rejected/ or DIR/mod/accepted/ for ‘reject’ and ‘accept’ requests, respectively.

If a valid reply is received but the message is no longer in DIR/mod/pending/, ezmlm-moderate(1) looks for the corresponding stub in DIR/mod/rejected/ and DIR/mod/accepted/. If the stub is found and the fate of the message was the one dictated by the new request, no further action is taken. If, however, no stub is found or the request and the actual message fate do not match, a notification is sent to the moderator. This scheme was chosen to impart a maximum of information with a minimum of messages. Also, it is the least demoralizing setup for multiple moderator lists, where it is important not to notify subsequent moderators that their work was in vain since the action of the first responding moderator has already resulted in processing of the message.

If a message is not ‘rejected’ or ‘accepted’ it remains in DIR/mod/pending/ until it times out. Cleanup of both messages and stubs is accomplished by ezmlm-clean(1) which is invoked through both DIR/editor and DIR/moderator for message moderated lists. ezmlm-clean(1) looks at the timestamp used to generate the message/stub name. If it is older than 120 hours (configurable in a range of 24-240 hours, by placing the value in DIR/modtime) it is removed. Unless suppressed with the ezmlm-clean(1) -R switch, the SENDER of the message is notified.

By default, the email addresses of message moderators are stored as a subscriber list with a basedir of DIR/mod/. This can be changed to any other basedir by placing the name of that directory with a leading ‘/’ in DIR/modpost. Although the default basedirs for message moderation and subscription moderation/remote administration are the same, both the functions and actors are entirely independent.