fix(web): send ws frames from httpd's context

Author: rednblkx

main/WebServerManager.cpp

@@ -1638,16 +1638,52 @@ esp_err_t WebServerManager::handleWifiScan(httpd_req_t *req) {
 // WebSocket Implementation
 // ============================================================================
 
+struct AsyncWsData {
+  httpd_handle_t server;
+  int fd;
+  httpd_ws_type_t type;
+  std::vector<uint8_t> payload;
+};
+
+static void send_ws_work_cb(void *arg) {
+  std::unique_ptr<AsyncWsData> data(static_cast<AsyncWsData *>(arg));
+
+  if (data) {
+    httpd_ws_frame_t ws_pkt = {};
+    ws_pkt.final = true;
+    ws_pkt.fragmented = false;
+    ws_pkt.type = data->type;
+    ws_pkt.len = data->payload.size();
+    ws_pkt.payload = data->payload.empty() ? nullptr : data->payload.data();
+
+    httpd_ws_send_frame_async(data->server, data->fd, &ws_pkt);
+  }
+}
+
 esp_err_t WebServerManager::ws_send_frame(httpd_handle_t server, int fd,
                                           const uint8_t *payload, size_t len,
                                           httpd_ws_type_t type) {
 #ifdef CONFIG_HTTPD_WS_SUPPORT
-  httpd_ws_frame_t ws_pkt = {.final = true,
-                             .fragmented = false,
-                             .type = type,
-                             .payload = const_cast<uint8_t *>(payload),
-                             .len = len};
-  return httpd_ws_send_frame_async(server, fd, &ws_pkt);
+  if (!server)
+    return ESP_FAIL;
+
+  auto data = std::make_unique<AsyncWsData>();
+  data->server = server;
+  data->fd = fd;
+  data->type = type;
+
+  if (len > 0 && payload) {
+    data->payload.assign(payload, payload + len);
+  }
+
+  AsyncWsData *raw_data = data.release();
+
+  esp_err_t ret = httpd_queue_work(server, send_ws_work_cb, raw_data);
+  if (ret != ESP_OK) {
+    std::unique_ptr<AsyncWsData> cleanup(raw_data);
+  }
+
+  return ret;
 #else
   return ESP_ERR_NOT_SUPPORTED;
 #endif