stream WebDAV downloads in chunks to prevent client disconnects

src/network/HttpFileStreamer.cpp

@@ -0,0 +1,44 @@
+#include "HttpFileStreamer.h"
+
+#include <Logging.h>
+#include <esp_task_wdt.h>
+
+namespace {
+constexpr size_t DOWNLOAD_CHUNK_SIZE = 4096;
+}
+
+namespace HttpFileStreamer {
+bool streamFileToClient(FsFile& file, NetworkClient& client) {
+  auto* buffer = static_cast<uint8_t*>(malloc(DOWNLOAD_CHUNK_SIZE));
+  if (!buffer) {
+    LOG_ERR("HTTP", "malloc failed: %zu bytes", DOWNLOAD_CHUNK_SIZE);
+    return false;
+  }
+
+  bool ok = true;
+  while (ok) {
+    esp_task_wdt_reset();
+    int result = file.read(buffer, DOWNLOAD_CHUNK_SIZE);
+    if (result < 0) {
+      ok = false;
+      break;
+    }
+    if (result == 0) break;
+
+    size_t bytesRead = static_cast<size_t>(result);
+    size_t totalWritten = 0;
+    while (totalWritten < bytesRead) {
+      esp_task_wdt_reset();
+      size_t wrote = client.write(buffer + totalWritten, bytesRead - totalWritten);
+      if (wrote == 0) {
+        ok = false;
+        break;
+      }
+      totalWritten += wrote;
+    }
+  }
+
+  free(buffer);
+  return ok;
+}
+}  // namespace HttpFileStreamer