Mailing List Archive: Binary data format for Maildir messages?

What defines when the “data” format is used to store the message?

The message ends up in some binary encoding and that makes it harder for me to test it thru my own filters with.

Is there a way to convert such messages to the text format to make testing easier?

For example of the messages looks like this

1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,

file 1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,
1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,: data

as opposed to messages that look like this

1686009696.6909_0.lhvm02:2,S

file 1686009696.6909_0.lhvm02:2,S
1686009696.6909_0.lhvm02:2,S: RFC 822 mail, ASCII text

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On 2023-06-05 at 20:19:19 UTC-0400 (Mon, 5 Jun 2023 19:19:19 -0500)
Robert Nicholson via Exim-users <robert.nicholson@gmail.com>
is rumored to have said:

> What defines when the “data” format is used to store the message?

A message file in an interoperable Maildir/Maildir++ structure is a text
file, as defined by RFC822 and its successors as well as the suite of
RFCs defining MIME.

There's a good description of Maildir at
https://www.courier-mta.org/maildir.html

> The message ends up in some binary encoding and that makes it harder
> for me to test it thru my own filters with.

Many messages are partially or fully encoded with Base64 or
Quoted-printable to allow for non-ASCII content. See the MIME RFCs.

> Is there a way to convert such messages to the text format to make
> testing easier?

That depends on what the message contains and why it was encoded.

>
> For example of the messages looks like this
>
> 1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,
>
> file 1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,
> 1686008819.M92410P2445.lhvm02.lizardhill.com,S=72137,W=74032:2,: data

Try actually looking at it yourself. The 'file' utility is imperfect at
identifying email as such.

> as opposed to messages that look like this
>
> 1686009696.6909_0.lhvm02:2,S
>
> file 1686009696.6909_0.lhvm02:2,S
> 1686009696.6909_0.lhvm02:2,S: RFC 822 mail, ASCII text

The difference in name formats is a function of how the specific message
was delivered, i.e. what tool created the message file. See the link
above for details.

--
Bill Cole
bill@scconsult.com or billcole@apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire

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