[Mailman-Users] Preventing accidental resubscription

Jeffrey Goldberg jeffrey at goldmark.org
Sun Aug 24 21:37:31 CEST 2008

On Aug 24, 2008, at 1:45 AM, Darrell Burkey wrote:

> I've had a client ask me how they can keep track of who unsubscribes  
> from their lists so that they don't accidentally resubscribe the  
> same address at some later point.

If they are properly confirming subscriptions, then there really  
shouldn't be any "accidental" re-subscriptions.  So this makes me  
suspicious about what your clients are up to.

> Unless anyone has any better advice I'm consider writinging a hack  
> to copy unsubscribe addresses to a file that can be checked before  
> subscribing someone.

When someone unsubscribes from a list, they may not want you to keep  
their email address at all.  I would recommend that you keep a hash of  
each unsubscribed email address instead of the email address itself.   
Of course that won't catch matches between, say,

              jeffrey at goldmark.org
              Jeffrey at goldmark.org

Those may or may not be "the same address".  You can safely lowercase  
the domain part of the email address, but I'm not sure what to do when  
creating the hash for addresses with uppercase in the local-part.



Jeffrey Goldberg                        http://www.goldmark.org/jeff/

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