eMail support status - best way forward

[DrRenz]

Hi folks,

I've recently come across the SMTP email feature of Tasmota and it has solved quite a few deployment issues for me (remote sites with just a handful of sensors, but no central infrastructure other than a 5G router).

However, I've run into some issues with connecting to non-Gmail SMTP servers, e.g. Postfix: While TLS and authentication work flawlessly, the sending of emails fails in the BDAT stage if the mail server supports chunking. This is reproducible using the latest ESP-Mail-Client library (3.4.24) standalone, so it's not Tasmota's fault. Either stopping the Postfix mail server from offering the "CHUNKING" option or setting "message.enable.chunking = false" as a workaround will solve the issue.

Since ESP-Mail-Client has been deprecated in favour of ReadyMail (by the same author), I wonder what the best way forward would be:

• Upgrade Tasmota to ReadyMail or another SMTP library altogether, potentially spending time and effort on customizing the SSL library integration again (/edit: ReadyMail's license prevents commercial use without paying the author. Quite certainly a no-go here.);
• Make Tasmota's ESP-Mail-Client configurable to enable/disable chunking; or
• Patch Tasmota's ESP-Mail-Client to never use chunking, even if the mail server supports it?

Now I understand that's just a side feature so it's definitely not the main focus, but please let me know if there are ways I can help here. Getting a better picture of the planned roadmap will avoid doing duplicate work.

Cheers, DrRenz

[arendst]

So would you benefit from adding a define EMAIL_DISABLE_CHUNKING like:

#ifdef EMAIL_DISABLE_CHUNKING
                message.enable.chunking = false;
#else
                message.enable.chunking = true;
#endif                
     

around line 219 in file xdrv_01_2_webserver_esp32_mail.ino.

If so, you will have to compile your own binary using the above define.

[DrRenz]

Yup, that would count as a viable workaround for me. I was a little hesitant to suggest it universally since I can't assess the resource impact of disabled chunking on more restricted devices like the ESP8266.

[arendst]

Alas, the solution is only available on ESP32.

[arendst]

Give it a try 4336cd0

[DrRenz]

Give it a try 4336cd0

Wow, thanks for the quick response! I'm travelling right now, so I'll check when I'm back home, but IMHO the patch should do the trick.

[DrRenz]

Back home and I can confirm the patch did the trick. Thanks a lot for including it in 16.0.0!