Re: [exim] Case-(In)sensitive Plus Addressing with Maildir D…

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Author: Rich, Whidbey Telecom
Date:  
To: exim-users
Subject: Re: [exim] Case-(In)sensitive Plus Addressing with Maildir Delivery?
On Mar 2, 2007, at 2:18 AM, Magnus Holmgren wrote:

> On Wednesday 28 February 2007 21:03, Rich, Whidbey Telecom wrote:
>> I've begun testing "plus addressing" to support the delivery of email
>> such as "user+topic@???" to a user-created IMAP folder:
>>
>> /var/mail/user/Maildir/.topic/new/
>>
>> [...
>> local_transport:
>>          driver = appendfile
>>          create_directory = false
>>          maildir_format = true
>>     ...
>>          directory = /var/mail/$local_part/Maildir${if exists{/var/
>> mail/$local_part/Maildir/.${substr_1:$local_part_suffix}}{/.$
>> {substr_1:$local_part_suffix}}{}}

>
> Tip: use match to avoid repetition:
>
>           directory = /var/mail/$local_part/Maildir${if match
>                  {$local_part_suffix}{.(.*)} {${if exists{/var/
>                   mail/$local_part/Maildir/.$1}{/.$1}}}}

>
> (with reservation for brace mismatch).
>


Thanks for the tip!

>> It delivers to the "topic" Maildir only if the user has already
>> created it. Otherwise, it's delivered to their top-level Maildir.
>>
>> However, I've hit a snag with the case-(in)sensitive nature of
>> addressing. Despite the RFC's, users are accustomed to the fact that
>> "user@???", "User@???" and "USER@???" will be
>> delivered to the same "user". Some systems and web-forms even
>> lowercase addresses. However, a message addressed to "user
>> +topic@???" doesn't match a directory named "Topic" on an ext3
>> filesystem.
>>
>> Does anyone have a suggestion to tell Exim how to deliver to "Topic",
>> even if the $local_part_suffix is "topic"? We realize one solution
>> is to force all IMAP folders to be lower-case, but would prefer to
>> explore other options.
>
> Do you want completely caseless matching or just transform
> everything to
> initial caps (optionally after trying "topic" as is)? The latter is
> relatively easy at least.


We'd preferrably like caseless matching (so that "user+sometopic"
could match "SomeTopic", "Sometopic", "SOMEtopic"). Is there anyone
using a caseless file system for mail storage, such as HFS+, in a
Linux production environment?

Otherwise, could we get "user+sometopic" to at least try "Sometopic",
since it's most common, before going to "topic", then a default Maildir?

Thanks again,

Rich