[pbs-devel] Superseded: Re: [PATCH proxmox 0/3] improve mail compatability

[Shannon Sterz]

On Tue Sep 2, 2025 at 4:27 PM CEST, Shannon Sterz wrote:
> this series tries to improve compatability with more mail servers. this
> is done in three ways:
>
> - patch 1: base64 encode filenames of attachments
> - patch 2: check whether the html or text bodies of an email are ascii
>   only. if they are, we can safely declare 7bit encoding which should be
>   more broadly compatability than the previous 8bit encoding. if the
>   text is not ascii only, encode it as base64 and declare base64
>   encoding.
> - patch 3: splits the Content-Disposition header of attached files over
>   two lines, to avoid longer files possibly triggering a line length
>   limit.
>
> this should specifically make it possible to support mail servers that
> don't support SMTPUTF8, as now no part of the header or body should
> contain plain utf8 characters directly.
>
> i tested these patches against the following mail clients:
>
> - bluemind
> - Thunderbird
> - aerc
> - canary [1]
> - iOS Mail app
> - gmail.com
> - outlook.com
>
> all of them seemed to receive the email and display it properly (note
> that aerc prefers the TXT part of the mime alternative parts even if the
> html part should be preferred, due to being a terminal based mua).
>
> [1]: https://canarymail.io/
>
> Shannon Sterz (3):
>   sendmail: encode non-ascii filenames to improve compatability
>   sendmail: encode non-ascii bodies as base64 to improve comptability
>   sendmail: break content disposition headers for attachments
>
>  proxmox-sendmail/src/lib.rs | 193 +++++++++++++++++++++++++++---------
>  1 file changed, 147 insertions(+), 46 deletions(-)
>
> --
> 2.47.2

Superseded-by: https://lore.proxmox.com/all/20251008084906.62427-1-s.sterz@proxmox.com/T/#t