Mass Stripping Attachments by Directory, Age, Size

[justina colmena ~biz]

Well ain't that rich? To use an allegory of sorts, we're going to have start using staples rather than paperclips 📎🖇️  with our email attachments, and one unified digital signature on the whole message as sent rather than a separate signature for each enclosure as commonly "done" with PGP, GnuPG, etc.

On March 30, 2021 7:39:02 PM AKDT, Plutocrat <plutocrat at gmail.com> wrote:
>Still can't find the magic solution to this.
>
>- My PERL isn't good enough to re-purpose strip-attachments.pl so it
>works on individual emails.
>- ripmime works to extract attachments only
>- altermime looked good and would delete all attachments from a
>directory of emails. However it messed up the structure somehow so they
>wouldn't display in an email client (Thunderbird, Roundcube).
>- mimeDEFANG looked possible, but couldn't figure out how to use that
>as a standalone script.
>- PHP solutions including the promising
>https://github.com/php-mime-mail-parser/php-mime-mail-parser seem only
>to be able to save attachments from the email, not delete it.
>
>I'll keep going I guess. I can't believe I'm the only person in the
>world to want to do this though ...
>
>P.
>
>On 19/03/2021 07.31, Joseph Tam wrote:
>> On Thu, 18 Mar 2021, Plutocrat wrote:
>> 
>>> I've been looking around for a solution to this problem. I want to
>prune down the attachments on a server before a migration. Some of the
>emails are 7 years old and have 40Mb attachments, so this seems like a
>good opportunity to rationalize things. So perhaps I'd like to "Remove
>all attachments from emails older than 2 years, in the .Sent
>directory", or "Attachments over 10Mb anywhere in the mail tree"
>>>
>>> I've found the strip_attachments.pl script here
><https://fossies.org/linux/Mail-Box/examples/strip-attachments.pl>
>which works fine on mbox (as tested on my local Thunderbird mboxes),
>but not on maildir which is on the dovecot server. My Perl isn't strong
>enough to re-purpose it.
>> 
>> It you have anything that works on mbox, it will probably work on
>Maildir
>> as each file can be considered a single message mbox.  You can
>combine
>> the script with
>> 
>>      find ~user/MailDir -type f ... -exec /path/to/mbox-strip {} \;
>> 
>> The ... can be replaced with more file tests (like minimum size or
>age
>> or only within */cur/) to cut down on processing.
>> 
>> I wrote a gawk script to slim down a multi-Gb Outlook mbox
>> for a user, but it wasn't really complicated, just matching for
>> /^Content-Transfer-Encoding:.*base64/i header (virtually all bulky
>data
>> will be encoded this way), buffering the base64 data part, then
>outputting
>> it if it was small, or deleting/replacing/extracting it otherwise.
>> 
>> It was a one-off discarded tool but I can hunt for it if you're hard
>up.
>> 
>>> I've looked at ripmime and mpack/munpack, and although they seem
>like useful tools to do the job of deconstructing the mail into its
>constituent parts, it doesn't seem to help in re-building the email. I
>think they could be used with a bit of study into mail MIME structure,
>and used with a helper script.
>>>
>>> So before I take a deep dive into scripting my own solution, I just
>wanted to check if anyone else on the list has been through this and
>has some resources or pointers they can share, or maybe even someone to
>tell me "Duh, you can do it with doveadm of course".
>> 
>> MIMEDefang may help.
>> 
>> Joseph Tam <jtam.home at gmail.com>

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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