(fix #94) Remove MAX_PRINTF_LEN limitation and fixed wrong usage of vsnprintf

examples/SimpleServer/SimpleServer.ino

@@ -26,6 +26,7 @@
 
 AsyncWebServer server(80);
 AsyncEventSource events("/events");
+AsyncWebSocket ws("/ws");
 
 const char* PARAM_MESSAGE PROGMEM = "message";
 const char* SSE_HTLM PROGMEM = R"(
@@ -195,7 +196,32 @@ void setup() {
     request->send(200, "text/html", SSE_HTLM);
   });
 
+  ws.onEvent([](AsyncWebSocket* server, AsyncWebSocketClient* client, AwsEventType type, void* arg, uint8_t* data, size_t len) {
+    (void) len;
+    if (type == WS_EVT_CONNECT) {
+      Serial.println("ws connect");
+      client->setCloseClientOnQueueFull(false);
+      client->ping();
+    } else if (type == WS_EVT_DISCONNECT) {
+      Serial.println("ws disconnect");
+    } else if (type == WS_EVT_ERROR) {
+      Serial.println("ws error");
+    } else if (type == WS_EVT_PONG) {
+      Serial.println("ws pong");
+    } else if (type == WS_EVT_DATA) {
+      AwsFrameInfo* info = (AwsFrameInfo*)arg;
+      String msg = "";
+      if (info->final && info->index == 0 && info->len == len) {
+        if (info->opcode == WS_TEXT) {
+          data[len] = 0;
+          Serial.printf("ws text: %s\n", (char*)data);
+        }
+      }
+    }
+  });
+
   server.addHandler(&events);
+  server.addHandler(&ws);
   server.addHandler(jsonHandler);
   server.addHandler(msgPackHandler);
 
@@ -205,12 +231,19 @@ void setup() {
 }
 
 uint32_t lastSSE = 0;
-uint32_t delta = 5;
+uint32_t deltaSSE = 5;
+
+uint32_t lastWS = 0;
+uint32_t deltaWS = 100;
 
 void loop() {
   uint32_t now = millis();
-  if (now - lastSSE >= delta) {
+  if (now - lastSSE >= deltaSSE) {
     events.send(String("ping-") + now, "heartbeat", now);
     lastSSE = millis();
   }
+  if (now - lastWS >= deltaWS) {
+    ws.printfAll("kp%.4f", (10.0 / 3.0));
+    lastWS = millis();
+  }
 }

src/AsyncWebSocket.cpp

@@ -36,11 +36,8 @@
   #include <Hash.h>
 #endif
 
-#define MAX_PRINTF_LEN 64
-
 using namespace asyncsrv;
 
-
 size_t webSocketSendFrameWindow(AsyncClient* client) {
   if (!client->canSend())
     return 0;
@@ -589,30 +586,23 @@ void AsyncWebSocketClient::_onData(void* pbuf, size_t plen) {
 size_t AsyncWebSocketClient::printf(const char* format, ...) {
   va_list arg;
   va_start(arg, format);
-  char* temp = new char[MAX_PRINTF_LEN];
-  if (!temp) {
-    va_end(arg);
-    return 0;
-  }
-  char* buffer = temp;
-  size_t len = vsnprintf(temp, MAX_PRINTF_LEN, format, arg);
+  size_t len = vsnprintf(nullptr, 0, format, arg);
   va_end(arg);
 
-  if (len > (MAX_PRINTF_LEN - 1)) {
-    buffer = new char[len + 1];
-    if (!buffer) {
-      delete[] temp;
+  if (len == 0)
     return 0;
-    }
+
+  char* buffer = new char[len + 1];
+
+  if (!buffer)
+    return 0;
+
   va_start(arg, format);
-    vsnprintf(buffer, len + 1, format, arg);
+  len = vsnprintf(buffer, len + 1, format, arg);
   va_end(arg);
-  }
+
   text(buffer, len);
-  if (buffer != temp) {
   delete[] buffer;
-  }
-  delete[] temp;
   return len;
 }
 
@@ -620,30 +610,23 @@ size_t AsyncWebSocketClient::printf(const char* format, ...) {
 size_t AsyncWebSocketClient::printf_P(PGM_P formatP, ...) {
   va_list arg;
   va_start(arg, formatP);
-  char* temp = new char[MAX_PRINTF_LEN];
-  if (!temp) {
-    va_end(arg);
-    return 0;
-  }
-  char* buffer = temp;
-  size_t len = vsnprintf_P(temp, MAX_PRINTF_LEN, formatP, arg);
+  size_t len = vsnprintf_P(nullptr, 0, formatP, arg);
   va_end(arg);
 
-  if (len > (MAX_PRINTF_LEN - 1)) {
-    buffer = new char[len + 1];
-    if (!buffer) {
-      delete[] temp;
+  if (len == 0)
     return 0;
-    }
+
+  char* buffer = new char[len + 1];
+
+  if (!buffer)
+    return 0;
+
   va_start(arg, formatP);
-    vsnprintf_P(buffer, len + 1, formatP, arg);
+  len = vsnprintf_P(buffer, len + 1, formatP, arg);
   va_end(arg);
-  }
+
   text(buffer, len);
-  if (buffer != temp) {
   delete[] buffer;
-  }
-  delete[] temp;
   return len;
 }
 #endif
@@ -1008,22 +991,24 @@ size_t AsyncWebSocket::printf(uint32_t id, const char* format, ...) {
 
 size_t AsyncWebSocket::printfAll(const char* format, ...) {
   va_list arg;
-  char* temp = new char[MAX_PRINTF_LEN];
-  if (!temp)
+  va_start(arg, format);
+  size_t len = vsnprintf(nullptr, 0, format, arg);
+  va_end(arg);
+
+  if (len == 0)
+    return 0;
+
+  char* buffer = new char[len + 1];
+
+  if (!buffer)
     return 0;
 
   va_start(arg, format);
-  size_t len = vsnprintf(temp, MAX_PRINTF_LEN, format, arg);
-  va_end(arg);
-  delete[] temp;
-
-  AsyncWebSocketSharedBuffer buffer = std::make_shared<std::vector<uint8_t>>(len);
-
-  va_start(arg, format);
-  vsnprintf((char*)buffer->data(), len + 1, format, arg);
+  len = vsnprintf(buffer, len + 1, format, arg);
   va_end(arg);
 
-  textAll(buffer);
+  textAll(buffer, len);
+  delete[] buffer;
   return len;
 }
 
@@ -1042,22 +1027,24 @@ size_t AsyncWebSocket::printf_P(uint32_t id, PGM_P formatP, ...) {
 
 size_t AsyncWebSocket::printfAll_P(PGM_P formatP, ...) {
   va_list arg;
-  char* temp = new char[MAX_PRINTF_LEN];
-  if (!temp)
+  va_start(arg, formatP);
+  size_t len = vsnprintf_P(nullptr, 0, formatP, arg);
+  va_end(arg);
+
+  if (len == 0)
+    return 0;
+
+  char* buffer = new char[len + 1];
+
+  if (!buffer)
     return 0;
 
   va_start(arg, formatP);
-  size_t len = vsnprintf_P(temp, MAX_PRINTF_LEN, formatP, arg);
-  va_end(arg);
-  delete[] temp;
-
-  AsyncWebSocketSharedBuffer buffer = std::make_shared<std::vector<uint8_t>>(len + 1);
-
-  va_start(arg, formatP);
-  vsnprintf_P((char*)buffer->data(), len + 1, formatP, arg);
+  len = vsnprintf_P(buffer, len + 1, formatP, arg);
   va_end(arg);
 
-  textAll(buffer);
+  textAll(buffer, len);
+  delete[] buffer;
   return len;
 }
 #endif