fixes webserver uploads and general stability

src/RecentBooksStore.cpp

@@ -52,6 +52,13 @@ void RecentBooksStore::clearAll() {
   Serial.printf("[%lu] [RBS] Cleared all recent books\n", millis());
 }
 
+void RecentBooksStore::clearFromMemory() {
+  const size_t count = recentBooks.size();
+  recentBooks.clear();
+  recentBooks.shrink_to_fit();  // Actually free the vector capacity
+  Serial.printf("[%lu] [RBS] Cleared %d recent books from memory (not saved)\n", millis(), count);
+}
+
 bool RecentBooksStore::saveToFile() const {
   // Make sure the directory exists
   SdMan.mkdir("/.crosspoint");

src/RecentBooksStore.h

@@ -29,9 +29,14 @@ class RecentBooksStore {
   // Returns true if the book was found and removed
   bool removeBook(const std::string& path);
 
-  // Clear all recent books from the list
+  // Clear all recent books from the list (and save to file)
   void clearAll();
 
+  // Clear recent books from memory without saving to file
+  // Used to free memory when entering modes that don't need this data (e.g., File Transfer)
+  // Call loadFromFile() to restore the data when needed again
+  void clearFromMemory();
+
   // Get the list of recent books (most recent first)
   const std::vector<RecentBook>& getBooks() const { return recentBooks; }
 

src/main.cpp

@@ -381,6 +381,15 @@ void onGoToListsOrPinned() {
 
 void onGoToFileTransfer() {
   exitActivity();
+
+  // Free memory not needed during file transfer to maximize heap for webserver
+  RECENT_BOOKS.clearFromMemory();
+  APP_STATE.openBookTitle.clear();
+  APP_STATE.openBookTitle.shrink_to_fit();
+  APP_STATE.openBookAuthor.clear();
+  APP_STATE.openBookAuthor.shrink_to_fit();
+  Serial.printf("[%lu] [FT] Cleared non-essential memory before File Transfer\n", millis());
+
   enterNewActivity(new CrossPointWebServerActivity(renderer, mappedInputManager, onGoHome));
 }
 
@@ -396,12 +405,24 @@ void onGoToClearCache() {
 
 void onGoToMyLibrary() {
   exitActivity();
+
+  // Reload recent books if they were cleared (e.g., when exiting File Transfer mode)
+  if (RECENT_BOOKS.getCount() == 0) {
+    RECENT_BOOKS.loadFromFile();
+  }
+
   enterNewActivity(
       new MyLibraryActivity(renderer, mappedInputManager, onGoHome, onGoToReader, onGoToListView, onGoToBookmarkList));
 }
 
 void onGoToMyLibraryWithTab(const std::string& path, MyLibraryActivity::Tab tab) {
   exitActivity();
+
+  // Reload recent books if they were cleared (e.g., when exiting File Transfer mode)
+  if (RECENT_BOOKS.getCount() == 0) {
+    RECENT_BOOKS.loadFromFile();
+  }
+
   enterNewActivity(new MyLibraryActivity(renderer, mappedInputManager, onGoHome, onGoToReader, onGoToListView,
                                          onGoToBookmarkList, tab, path));
 }
@@ -413,6 +434,12 @@ void onGoToBrowser() {
 
 void onGoHome() {
   exitActivity();
+
+  // Reload recent books if they were cleared (e.g., when exiting File Transfer mode)
+  if (RECENT_BOOKS.getCount() == 0) {
+    RECENT_BOOKS.loadFromFile();
+  }
+
   enterNewActivity(new HomeActivity(renderer, mappedInputManager, onContinueReading, onGoToListsOrPinned,
                                     onGoToMyLibrary, onGoToSettings, onGoToFileTransfer, onGoToBrowser));
 }

src/network/CrossPointWebServer.cpp

@@ -441,17 +441,33 @@ void CrossPointWebServer::handleFileListData() const {
     showHidden = server->arg("showHidden") == "true";
   }
 
+  // Check client connection before starting
+  if (!server->client().connected()) {
+    Serial.printf("[%lu] [WEB] Client disconnected before file list could start\n", millis());
+    return;
+  }
+
   server->setContentLength(CONTENT_LENGTH_UNKNOWN);
   server->send(200, "application/json", "");
-  server->sendContent("[");
+  if (!sendContentSafe("[")) {
+    Serial.printf("[%lu] [WEB] Client disconnected at start of file list\n", millis());
+    return;
+  }
+
   char output[512];
   constexpr size_t outputSize = sizeof(output);
   bool seenFirst = false;
+  bool clientDisconnected = false;
   JsonDocument doc;
 
   scanFiles(
       currentPath.c_str(),
-      [this, &output, &doc, seenFirst](const FileInfo& info) mutable {
+      [this, &output, &doc, &seenFirst, &clientDisconnected](const FileInfo& info) mutable {
+        // Skip remaining files if client already disconnected
+        if (clientDisconnected) {
+          return;
+        }
+
         doc.clear();
         doc["name"] = info.name;
         doc["size"] = info.size;
@@ -475,18 +491,33 @@ void CrossPointWebServer::handleFileListData() const {
           return;
         }
 
+        // Send comma separator before all entries except the first
         if (seenFirst) {
-          server->sendContent(",");
+          if (!sendContentSafe(",")) {
+            clientDisconnected = true;
+            Serial.printf("[%lu] [WEB] Client disconnected during file list\n", millis());
+            return;
+          }
         } else {
           seenFirst = true;
         }
-        server->sendContent(output);
+
+        // Send the JSON entry with flow control
+        if (!sendContentSafe(output)) {
+          clientDisconnected = true;
+          Serial.printf("[%lu] [WEB] Client disconnected during file list\n", millis());
+          return;
+        }
       },
       showHidden);
-  server->sendContent("]");
+
+  // Only send closing bracket if client is still connected
+  if (!clientDisconnected) {
+    sendContentSafe("]");
     // End of streamed response, empty chunk to signal client
     server->sendContent("");
     Serial.printf("[%lu] [WEB] Served file listing page for path: %s\n", millis(), currentPath.c_str());
+  }
 }
 
 // Static variables for upload handling
@@ -1264,6 +1295,40 @@ void CrossPointWebServer::handleRename() const {
   }
 }
 
+// Counter for flow control pacing
+static uint8_t sendContentCounter = 0;
+
+bool CrossPointWebServer::sendContentSafe(const char* content) const {
+  if (!server || !server->client().connected()) {
+    return false;
+  }
+
+  // Send the content
+  server->sendContent(content);
+
+  // Flow control: give TCP stack time to transmit data and drain the send buffer
+  // The ESP32 TCP buffer is limited and fills quickly when streaming many small chunks.
+  // We use progressive delays:
+  // - yield() after every send to allow WiFi processing
+  // - delay(5ms) every send to allow buffer draining
+  // - delay(50ms) every 10 sends to allow larger buffer flush
+  yield();
+  sendContentCounter++;
+
+  if (sendContentCounter >= 10) {
+    sendContentCounter = 0;
+    delay(50);  // Longer pause every 10 sends for buffer catchup
+  } else {
+    delay(5);   // Short pause each send
+  }
+
+  return server->client().connected();
+}
+
+bool CrossPointWebServer::sendContentSafe(const String& content) const {
+  return sendContentSafe(content.c_str());
+}
+
 bool CrossPointWebServer::copyFile(const String& srcPath, const String& destPath) const {
   FsFile srcFile;
   FsFile destFile;

src/network/CrossPointWebServer.h

@@ -108,6 +108,11 @@ class CrossPointWebServer {
   bool copyFile(const String& srcPath, const String& destPath) const;
   bool copyFolder(const String& srcPath, const String& destPath) const;
 
+  // Helper for safe content sending with flow control
+  // Returns false if client disconnected, true otherwise
+  bool sendContentSafe(const char* content) const;
+  bool sendContentSafe(const String& content) const;
+
   // List management handlers
   void handleListGet() const;
   void handleListPost() const;