Reimplementing WebSockets

[vortigont]

Hey team, long time! family matters, you know...
but I've returned with something new. Took my time to re-implement websockets from scratch.

• created a newer more abstracted design pattern for message containers, gives more freedom to accommodate various objects
• incoming message reassembly that spans multiple TCP packets
• queue/message size limit with graceful disconnection
• server side message replication
• multiple endpoint handling with one server instance
• optional server worker that decouples user callbacks handling from AsyncTCP (yes, finally!)
• some other things...

I decided to give away all backward compatibility to untie my hands and implemented all in a separate classes within a single .cpp unit, ESP32/C++17 minimum, other platforms I do not have in possession for now.

This all is highly experimental for now, still work in progress with a bunch of features to be implemented. But I've created some examples for evaluation and early feedback if any (esp32cam is most funny one to play with).

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[mathieucarbou]

@vortigont : as you proposed, would you be able to refresh your PR but move the code in other classes (like WebSocketv2) so that we could have both implementation side by side for now to avoid breaking changes ?

[mathieucarbou]

@vortigont : I tested the PR in a project and indeed this is not a breaking change PR - the classes are isolated.

I had to do some changed though:

1. To supports Arduino String

2. To set the handler not directly from the constructor (in some cases this is not possible when the WS server is a class field with the handler being a method of this class). Example: _ws.setEventHandler(std::bind(&WebApiWsLiveClass::onWebsocketEvent, this, _1, _2));

diff --git a/src/AsyncWSocket.h b/src/AsyncWSocket.h
index d45fe30..4944c93 100644
--- a/src/AsyncWSocket.h
+++ b/src/AsyncWSocket.h
@@ -167,7 +167,20 @@ public:
 
   // variadic constructor for anything that T can be made of
   template<typename... Args>
-  WSMessageContainer (WSFrameType_t t, bool final, Args&&... args) : WSMessageGeneric(t, final), container(std::forward<Args>(args)...) {};
+  WSMessageContainer (WSFrameType_t t, bool final, Args&&... args) : WSMessageGeneric(t, final), container(_convertArg(std::forward<Args>(args))...) {};
+
+private:
+  // Helper to convert Arduino String to const char* for std::string compatibility
+  template<typename Arg>
+  static auto _convertArg(Arg&& arg) {
+    if constexpr (std::is_same_v<std::decay_t<Arg>, String>) {
+      return arg.c_str();
+    } else {
+      return std::forward<Arg>(arg);
+    }
+  }
+
+public:
 
   /**
    * @copydoc WSMessageGeneric::getSize()
@@ -983,6 +996,10 @@ public:
     _handshakeHandler = handler;
   }
 
+  void setEventHandler(WSocketClient::event_cb_t handler) {
+    eventHandler = handler;
+  }
+
   /**
    * @brief callback for AsyncServer - onboard new ws client
    * 

3. Why restricting to ESP-IDF 5 ? The project I tried into is using Arduino Core 2... It seems to work without the macro:

diff --git a/src/AsyncWSocket.cpp b/src/AsyncWSocket.cpp
index b4aa967..94dafe4 100644
--- a/src/AsyncWSocket.cpp
+++ b/src/AsyncWSocket.cpp
@@ -7,7 +7,6 @@
 #if __cplusplus >= 201703L
 #include "AsyncWSocket.h"
 #if defined(ESP32)
-#if (ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0))
 #include "literals.h"
 
 #define WS_MAX_HEADER_SIZE  16
@@ -1036,6 +1035,5 @@ void WSocketServerWorker::_taskRunner(){
   vTaskDelete(NULL);
 }
 
-#endif  // (ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0))
 #endif  // defined(ESP32)
 #endif  // __cplusplus >= 201703L

4. Could you please rebase and move your code into a feature branch feature/new-ws in the asyncws repo so that all the team can participate ?