Add LibreTiny support

[kuba2k2]

This PR introduces a series of non-breaking changes that make it possible to use latest ESPAsyncWebServer on LibreTiny platform (BK72xx, RTL87xx).

Previously, this was supported in https://github.com/esphome/ESPAsyncWebServer and used in ESPHome this way. That library is unmaintained, so I'm introducing support for LibreTiny in the updated version by ESP32Async. When it gets released, the web server used by ESPHome may be updated to ^v3.7.7 (in this PR: esphome/esphome#8867).

The AsyncTCP implementation used for LibreTiny is https://github.com/esphome/AsyncTCP - it is the same one used for the few last years, so it's well-tested and stable.

This was tested and verified working on BK7231N and RTL8710BN.

[Copilot]

Pull Request Overview

This PR adds LibreTiny platform support to ESPAsyncWebServer by introducing conditional code branches for LIBRETINY alongside existing platforms and by adding a new dependency (AsyncTCP-esphome). Key changes include updates to preprocessor conditionals across several source files, integration of mbedtls-based SHA1 calculation for LibreTiny, and updated documentation and library metadata.

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/literals.h	Added extern declaration and macro alias for emptyString for LIBRETINY support.
src/WebServer.cpp	Defined emptyStringForEspAsync for LIBRETINY compilation.
src/WebRequest.cpp	Updated conditional checks to include LIBRETINY when using legacy String methods.
src/WebHandlers.cpp	Added LIBRETINY branches for etag generation.
src/Middleware.cpp	Adjusted client IP printing logic to support LibreTiny.
src/ESPAsyncWebServer.h	Extended platform conditionals to include LIBRETINY for AsyncTCP.
src/AsyncWebSocket.h	Updated preprocessor conditions to include LIBRETINY.
src/AsyncWebSocket.cpp	Integrated mbedtls SHA1 implementation for LibreTiny.
src/AsyncEventSource.h	Updated conditionals for LIBRETINY support.
library.json	Added LibreTiny platform and relevant dependency changes.
README.md	Documented the new AsyncTCP-esphome dependency and LibreTiny usage.

[mathieucarbou]

@kuba2k2 : do you want to look into this compile issue (ESP32Async/AsyncTCP#64) before I release AsyncTCP and before you can resume this PR ? Or we simply drop support for generic-rtl8710bn-2mb-788k ?

[kuba2k2]

I will look into that.

[kuba2k2]

It's upgraded to v3.4.3 now - I'll let the CI do the rest 😄

[mathieucarbou]

is it safe to have it defined globally ? Could it conflict with other libs ?

[mathieucarbou]

@kuba2k2 : your PR is ready to be rebased on main: there are some conflicts.
Plus 2 comments to look at.
Thank you 👍

[mathieucarbou]

@kuba2k2 : please let me know if you'll have time to revisit this PR, or if you can open your branch to maintainers so that I can continue within this same PR. Thanks!

[kuba2k2]

Hi
I have the changes ready, but I'm waiting for LibreTiny v1.9.1 to be available on PlatformIO Registry. Once it is, I will push the changes.

[kuba2k2]

The PR is now updated to use LibreTiny v1.9.1, since it's now available on PlatformIO Registry.
There is also a new CI workflow.

[mathieucarbou]

@kuba2k2 : build is failing....

[kuba2k2]

That's because DNSServer library is not available in LT, ESPHome uses this instead: https://registry.platformio.org/libraries/bbx10/DNSServer
The examples will have to be updated.

[mathieucarbou]

@kuba2k2 : could you please rebase ? I cannot update your branch. Thanks!

[kuba2k2]

There you go.
It seems that I can't enable writing to my branch by maintainers, perhaps because it's a PR from libretiny-eu organization.

But anyway, I also enabled WiFi related code on LT, so CI should now pass (I tested the AsyncResponseStream example locally and it compiles fine).

[mathieucarbou]

@kuba2k2 : CI still not passing...

[swoboda1337]

If we could get this merged soon that would great. I am trying to move ESPHome to use this and having LibreTiny support would simplify that effort. Thanks!

[kuba2k2]

I will try to fix CI.
@swoboda1337 there already is a PR to ESPHome that updates ESPAsyncWebServer and enables web_server on RP2040.

[swoboda1337]

I will try to fix CI. @swoboda1337 there already is a PR to ESPHome that updates ESPAsyncWebServer and enables web_server on RP2040.

Ok yeah I see it, I basically did the same thing. I need this for the Arduino 3 PR, can join the discord discussion here https://discord.com/channels/429907082951524364/1377029109758038087

[swoboda1337]

If you can get this LibreTiny PR merged hopefully we can get esphome/esphome#8867 merged with the Arduino 3 PR next week. Want to get it merged after the release.

[kuba2k2]

Some of the examples are ESP-specific, for example they use LittleFS.
I would suggest only keeping a few of the examples in LibreTiny CI. It doesn't really make sense to compile all of them anyway..

[mathieucarbou]

Some of the examples are ESP-specific, for example they use LittleFS. I would suggest only keeping a few of the examples in LibreTiny CI. It doesn't really make sense to compile all of them anyway..

Like I said, I cannot edit the PR to add a new commit.

I suggest you can replace the loop with a list of example names you know will compile then.

Thanks!

[mathieucarbou]

Thanks!

Release v3.7.8 is in progress...

[swoboda1337]

Excellent thanks