[ai] memory optimizations

src/DirectoryNode.cpp

@@ -1,6 +1,10 @@
 #include "DirectoryNode.h"
 #include "globals.h"
 #include <algorithm>
+#include <cstring>    // strlen, strlcpy, strlcat
+#include <strings.h>  // strcasecmp
+
+char DirectoryNode::buffer[DirectoryNode::buffer_size];
 
 DirectoryNode::DirectoryNode(const String &nodeName)
     : name(nodeName), currentPlaying("")
@@ -42,14 +46,7 @@ const String &DirectoryNode::getDirPath() const
     return dirPath;
 }
 
-String DirectoryNode::getFullPathByIndex(size_t index) const
+
-{
-    if (index < mp3Files.size())
-    {
-        return buildFullPath(mp3Files[index]);
-    }
-    return String();
-}
 
 String DirectoryNode::buildFullPath(const String &fileName) const
 {
@@ -65,11 +62,49 @@ String DirectoryNode::buildFullPath(const String &fileName) const
     return p;
 }
 
+bool DirectoryNode::comparePathWithString(const char* path, const String& target) const
+{
+    // Convert target to char* for comparison
+    const char* targetStr = target.c_str();
+    
+    // Case-insensitive string comparison
+    return strcasecmp(path, targetStr) == 0;
+}
+
+void DirectoryNode::buildFullPath(const String &fileName, char* out, size_t n) const
+{
+    if (n == 0) return;
+    out[0] = '\0';
+
+    if (dirPath == "/")
+    {
+        strlcat(out, "/", n);
+    }
+    else
+    {
+        strlcpy(out, dirPath.c_str(), n);
+        strlcat(out, "/", n);
+    }
+
+    strlcat(out, fileName.c_str(), n);
+}
+
 void DirectoryNode::setCurrentPlaying(const String &mp3File)
 {
     bool isAbs = (mp3File.length() > 0) && (mp3File.charAt(0) == '/');
     const String &fileName = isAbs ? mp3File.substring(mp3File.lastIndexOf('/') + 1) : mp3File;
-    currentPlaying = isAbs ? mp3File : buildFullPath(fileName);
+    
+    if (isAbs)
+    {
+        currentPlaying = mp3File;  // Already absolute path
+    }
+    else
+    {
+        // Use buffer for building relative path
+        buildFullPath(fileName, buffer, buffer_size);
+        currentPlaying = String(buffer);  // Convert back to String for assignment
+    }
+    
     for (size_t i = 0; i < mp3Files.size(); i++)
     {
         if (mp3Files[i] == fileName && ids.size() > i)
@@ -128,9 +163,6 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
     subdirectories.clear();
     mp3Files.clear();
     ids.clear();
-    subdirectories.shrink_to_fit();
-    mp3Files.shrink_to_fit();
-    ids.shrink_to_fit();
 
     // Set directory path for this node (normalize: keep "/" or remove trailing slash)
     String path = String(currentPath);
@@ -145,6 +177,12 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
     std::vector<String> fileNames;
 
     File rootDir = SD.open(currentPath);
+    if (!rootDir)
+    {
+        Serial.print(F("buildDirectoryTree: failed to open path: "));
+        Serial.println(currentPath);
+        return;
+    }
     while (true)
     {
         File entry = rootDir.openNextFile();
@@ -153,7 +191,7 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
             break;
         }
 
-        if (entry.isDirectory() && entry.name()[0] != '.' && strcmp(entry.name(), sys_dir))
+        if (entry.isDirectory() && entry.name()[0] != '.' && strcmp(entry.name(), sys_dir) != 0)
         {
             dirNames.emplace_back(entry.name());
         }
@@ -195,12 +233,26 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
     for (const String &dirName : dirNames)
     {
         DirectoryNode *newNode = new DirectoryNode(dirName);
+        if (!newNode)
+        {
+            Serial.println(F("buildDirectoryTree: OOM creating DirectoryNode"));
+            continue;
+        }
         subdirectories.push_back(newNode);
 
-        String childPath = String(currentPath);
+        String childPath;
-        if (!childPath.endsWith("/"))
+        childPath.reserve(dirPath.length() + 1 + dirName.length());
+        if (dirPath == "/")
+        {
+            childPath = "/";
+            childPath += dirName;
+        }
+        else
+        {
+            childPath = dirPath;
             childPath += "/";
-        childPath += dirName;
+            childPath += dirName;
+        }
 
         newNode->buildDirectoryTree(childPath.c_str());
     }
@@ -220,16 +272,19 @@ void DirectoryNode::printDirectoryTree(int level) const
         Serial.print(F("  "));
     }
     Serial.println(name);
-
+    
     for (const String &mp3File : mp3Files)
     {
         for (int i = 0; i <= level; i++)
         {
             Serial.print(F("  "));
         }
-        Serial.println(buildFullPath(mp3File));
+        
+        // Use buffer for building path
+        buildFullPath(mp3File, buffer, buffer_size);
+        Serial.println(buffer);
     }
-
+    
     for (DirectoryNode *childNode : subdirectories)
     {
         childNode->printDirectoryTree(level + 1);
@@ -274,7 +329,8 @@ DirectoryNode *DirectoryNode::advanceToMP3(const uint16_t id)
         if (id == ids[i])
         {
             // Found the current MP3 file
-            currentPlaying = buildFullPath(mp3Files[i]);
+            buildFullPath(mp3Files[i], buffer, buffer_size);
+            currentPlaying = String(buffer);  // Convert back to String for assignment
             currentPlayingId = id;
             return this;
         }
@@ -329,7 +385,9 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String &songName)
     {
         if (isAbsolutePath)
         {
-            if (buildFullPath(mp3Files[i]).equalsIgnoreCase(songName))
+            // Use static buffer for path building and comparison
+            buildFullPath(mp3Files[i], buffer, buffer_size);
+            if (comparePathWithString(buffer, songName))
             {
                 setCurrentPlaying(mp3Files[i]);
                 return this;
@@ -337,7 +395,9 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String &songName)
         }
         else
         {
-            String f = mp3Files[i];
+            // Use static buffer for case conversion and comparison
+            buildFullPath(mp3Files[i], buffer, buffer_size);
+            String f = String(buffer);
             f.toLowerCase();
             if (f.endsWith(lowTarget))
             {
@@ -431,7 +491,8 @@ DirectoryNode *DirectoryNode::goToPreviousMP3(uint32_t thresholdSeconds)
     int currentIndex = -1;
     for (size_t i = 0; i < mp3Files.size(); i++)
     {
-        if (currentPlaying == buildFullPath(mp3Files[i]))
+        buildFullPath(mp3Files[i], buffer, buffer_size);
+        if (comparePathWithString(buffer, currentPlaying))
         {
             currentIndex = i;
             break;
@@ -442,7 +503,7 @@ DirectoryNode *DirectoryNode::goToPreviousMP3(uint32_t thresholdSeconds)
     if (currentIndex > 0)
     {
         Serial.print(F("goToPreviousMP3: Moving to previous song in same directory: "));
-        Serial.println(buildFullPath(mp3Files[currentIndex - 1]));
+        Serial.println(mp3Files[currentIndex - 1]);
         setCurrentPlaying(mp3Files[currentIndex - 1]);
         return this;
     }
@@ -471,7 +532,9 @@ DirectoryNode *DirectoryNode::findPreviousMP3Globally(const String &currentGloba
     {
         DirectoryNode *node = allMP3s[i].first;
         int fileIndex = allMP3s[i].second;
-        if (node->buildFullPath(node->mp3Files[fileIndex]) == currentGlobal)
+        
+        node->buildFullPath(node->mp3Files[fileIndex], buffer, buffer_size);
+        if (comparePathWithString(buffer, currentGlobal))
         {
             currentGlobalIndex = i;
             break;
@@ -483,10 +546,12 @@ DirectoryNode *DirectoryNode::findPreviousMP3Globally(const String &currentGloba
     {
         DirectoryNode *prevNode = allMP3s[currentGlobalIndex - 1].first;
         int prevFileIndex = allMP3s[currentGlobalIndex - 1].second;
-
+        
+        prevNode->buildFullPath(prevNode->mp3Files[prevFileIndex], buffer, buffer_size);
+        
         Serial.print(F("findPreviousMP3Globally: Moving to previous song globally: "));
-        Serial.println(prevNode->buildFullPath(prevNode->mp3Files[prevFileIndex]));
+        Serial.println(buffer);
-
+        
         prevNode->setCurrentPlaying(prevNode->mp3Files[prevFileIndex]);
         return prevNode;
     }
@@ -525,7 +590,8 @@ DirectoryNode *DirectoryNode::advanceToNextMP3(const String &currentGlobal)
     {
         for (size_t i = 0; i < mp3Files.size(); i++)
         {
-            if (currentGlobal == buildFullPath(mp3Files[i]))
+            buildFullPath(mp3Files[i], buffer, buffer_size);
+            if (currentGlobal == String(buffer))
             {
                 // Found the current playing MP3 file
                 if (i < mp3Files.size() - 1)
@@ -555,7 +621,8 @@ DirectoryNode *DirectoryNode::advanceToNextMP3(const String &currentGlobal)
         // Have each subdirectory advance its song
         for (size_t i = 0; i < subdir->mp3Files.size(); i++)
         {
-            if (currentGlobal == subdir->buildFullPath(subdir->mp3Files[i]))
+            subdir->buildFullPath(subdir->mp3Files[i], buffer, buffer_size);
+            if (currentGlobal == String(buffer))
             {
                 // Found the current playing MP3 file
                 if (i < subdir->mp3Files.size() - 1)
@@ -603,10 +670,11 @@ void DirectoryNode::streamDirectoryHTML(Print &out) const {
         out.print(F("<li data-id=\""));
         out.print(ids[i]);
         out.print(F("\">"));
-        out.print(buildFullPath(mp3Files[i]));
+        buildFullPath(mp3Files[i], buffer, buffer_size);
+        out.print(buffer);
         out.println(F("</li>"));
 #ifdef DEBUG        
-        Serial.printf("stream song: %s\n", buildFullPath(mp3Files[i]).c_str());
+        Serial.printf("stream song: %s\n", buffer);
 #endif        
         // Yield every few items to allow the async web server to send buffered data
         if (i % 5 == 4) {
@@ -614,6 +682,8 @@ void DirectoryNode::streamDirectoryHTML(Print &out) const {
         }
     }
 
+    out.flush();
+
     for (DirectoryNode* child : subdirectories) {
         child->streamDirectoryHTML(out);
     }

src/DirectoryNode.h

@@ -18,11 +18,17 @@ private:
   std::vector<DirectoryNode*> subdirectories;
   std::vector<String> mp3Files;
   std::vector<uint16_t> ids;
+  static const size_t path_size = 256;
   String currentPlaying;
   uint16_t currentPlayingId = 0;
   uint16_t secondsPlayed = 0;
+  static const size_t buffer_size = path_size;
+  static char buffer[buffer_size];
   
   String buildFullPath(const String& fileName) const;
+  void buildFullPath(const String &fileName, char* buffer, size_t bufferSize) const;
+  bool comparePathWithString(const char* path, const String& target) const;
+
    
 
 public:
@@ -36,7 +42,6 @@ public:
   const std::vector<DirectoryNode*>& getSubdirectories() const;
   const std::vector<String>& getMP3Files() const;
   const String& getDirPath() const;
-  String getFullPathByIndex(size_t index) const;
 
   size_t getNumOfFiles() const;
 

src/globals.h

@@ -31,7 +31,7 @@ static const char* hdr_connection_key = "Connection";
 
 static const char* hdr_connection_val = "close";
 
-const size_t buffer_size = 256;
+const size_t buffer_size = 80;
 
 
 /*

src/main.cpp

@@ -28,6 +28,39 @@
 // webrequest_blockings is a simple watchdog counter that tracks how long at least one HTTP request has been “active” (not yet disconnected) according to the AsyncWebServer.
 int webrequest_blockings = 0;
 
+// Prebuilt system paths to avoid repeated String allocations
+static String SYS_PREFIX;
+static String PATH_INDEX, PATH_INDEX_GZ, PATH_STYLE, PATH_STYLE_GZ, PATH_SCRIPT, PATH_SCRIPT_GZ;
+static String PATH_MAPPING, PATH_PROGRESS, PATH_CONFIG, PATH_SLEEP, PATH_STARTUP;
+
+static inline void buildSystemPathsOnce() {
+  if (!SYS_PREFIX.isEmpty()) return;
+
+  SYS_PREFIX = "/";
+  SYS_PREFIX += sys_dir;
+  SYS_PREFIX += "/";
+
+  auto make = [](const char* name) {
+    String s;
+    s = SYS_PREFIX;
+    s += name;
+    return s;
+  };
+
+  PATH_INDEX   = make(index_file);
+  PATH_STYLE   = make(style_file);
+  PATH_SCRIPT  = make(script_file);
+  PATH_MAPPING = make(mapping_file);
+  PATH_PROGRESS= make(progress_file);
+  PATH_CONFIG  = make(config_file);
+  PATH_SLEEP   = make(sleep_sound);
+  PATH_STARTUP = make(startup_sound);
+
+  PATH_INDEX_GZ  = PATH_INDEX;  PATH_INDEX_GZ  += F(".gz");
+  PATH_STYLE_GZ  = PATH_STYLE;  PATH_STYLE_GZ  += F(".gz");
+  PATH_SCRIPT_GZ = PATH_SCRIPT; PATH_SCRIPT_GZ += F(".gz");
+}
+
 
 void activateSD()
 {
@@ -118,27 +151,7 @@ void handleUpload(AsyncWebServerRequest *request, String filename, size_t index,
     filepath += filename;
     if (SD.exists(filepath))
     {
-      String baseName = filename.substring(0, filename.lastIndexOf('.'));
+      request->send(500, txt_plain, F("File already exists."));
-      String extension = filename.substring(filename.lastIndexOf('.'));
-      int counter = 1;
-      filepath.reserve(1 + baseName.length() + 1 + 10 + extension.length());
-      do
-      {
-        filepath = "/";
-        filepath += baseName;
-        filepath += "_";
-        filepath += counter;
-        filepath += extension;
-        counter++;
-      } while (SD.exists(filepath) && counter < 100);
-
-      if (counter >= 100)
-      {
-        request->send(409, txt_plain, F("Too many files w sim names"));
-        return;
-      }
-      Serial.print(F("File exists, using: "));
-      Serial.println(filepath);
     }
 
     // Open the file for writing (guard with simple mutex)
@@ -266,9 +279,6 @@ uint32_t getBatteryVoltageMv()
 {
   uint32_t voltage = analogReadMilliVolts(BAT_VOLTAGE_PIN);
   voltage *= 2; //*2 because of the voltage divider.
-  // Serial.print("Battery Voltage: ");
-  // Serial.println(voltage);
-  // Serial.println(" mV");
   return voltage;
 }
 
@@ -735,7 +745,7 @@ void editMapping(AsyncWebServerRequest *request)
     }
 
     rfid_map[rfid] = MappingEntry(song, mode);
-    saveMappingToFile(getSysDir(mapping_file));
+    saveMappingToFile(PATH_MAPPING);
     request->send_P(200, txt_plain, PSTR("Mapping updated"));
   }
   else
@@ -901,6 +911,7 @@ static void streamMappingHTML(Print &out)
     out.print(pair.second.mode);
     out.print(F("</td></tr>"));
     // Yield occasionally if async server is buffering
+    out.flush();
     yield();
   }
   out.print(F("</table>"));
@@ -975,7 +986,7 @@ void togglePlayPause()
 {
   if (currentNode != NULL)
   {
-    writeSongProgress(getSysDir(progress_file).c_str(), currentNode->getCurrentPlayingId(), currentNode->getSecondsPlayed());
+    writeSongProgress(PATH_PROGRESS.c_str(), currentNode->getCurrentPlayingId(), currentNode->getSecondsPlayed());
     audio.pauseResume();
   }
   else
@@ -1247,37 +1258,22 @@ static void serveStaticFile(AsyncWebServerRequest *request,
 }
 
 void init_webserver() {
+
     server.on("/", HTTP_GET, [](AsyncWebServerRequest *request)
               {
-                static String htmlPath = "";
+                serveStaticFile(request, PATH_INDEX, PATH_INDEX_GZ, txt_html_charset, hdr_cache_control_val, F("ERROR: /system/index.html(.gz) not found!"), true);
-                static String htmlPathGz = "";
+                
-                if (htmlPath.isEmpty()) {
+
-                  htmlPath = getSysDir(index_file);
-                  htmlPathGz = htmlPath + F(".gz");
-                }
-                serveStaticFile(request, htmlPath, htmlPathGz, txt_html_charset, hdr_cache_control_val, F("ERROR: /system/index.html(.gz) not found!"), true);
               });
 
     server.on("/style.css", HTTP_GET, [](AsyncWebServerRequest *request)
               {
-                static String cssPath = "";
+                serveStaticFile(request, PATH_STYLE, PATH_STYLE_GZ, "text/css", "public, max-age=300", F("ERROR: /system/style.css(.gz) not found!"), true);
-                static String cssPathGz = "";
-                if (cssPath.isEmpty()) {
-                  cssPath = getSysDir(style_file);
-                  cssPathGz = cssPath + F(".gz");
-                }
-                serveStaticFile(request, cssPath, cssPathGz, "text/css", "public, max-age=300", F("ERROR: /system/style.css(.gz) not found!"), true);
               });
 
     server.on("/script.js", HTTP_GET, [](AsyncWebServerRequest *request)
               {
-                static String jsPath = "";
+                serveStaticFile(request, PATH_SCRIPT, PATH_SCRIPT_GZ, "application/javascript", "public, max-age=300", F("ERROR: /system/script.js(.gz) not found!"), true);
-                static String jsPathGz = "";
-                if (jsPath.isEmpty()) {
-                  jsPath = getSysDir(script_file);
-                  jsPathGz = jsPath + F(".gz");
-                }
-                serveStaticFile(request, jsPath, jsPathGz, "application/javascript", "public, max-age=300", F("ERROR: /system/script.js(.gz) not found!"), true);
               });
 
     // Dynamic endpoints to avoid template processing heap spikes
@@ -1287,9 +1283,7 @@ void init_webserver() {
                 request->onDisconnect([](){ webreq_exit(); });
                 // Stream the response directly from the directory tree to avoid large temporary Strings
                 AsyncResponseStream* stream = request->beginResponseStream(txt_html_charset, buffer_size);
-#ifdef DEBUG                
+                Serial.printf("Serving /directory heap=%u webreq_cnt=%u numOfFiles=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt, rootNode.getNumOfFiles());                
-                Serial.printf("Serving /directory heap=%u webreq_cnt=%u numOfFiles=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt, rootNode.getNumOfFiles());
-#endif                
                 stream->addHeader(hdr_cache_control_key, hdr_cache_control_val);
                 stream->addHeader(hdr_connection_key, hdr_connection_val);
                 // Generate HTML directly into the stream under lock
@@ -1303,7 +1297,7 @@ void init_webserver() {
                 request->onDisconnect([](){ webreq_exit();});
                 // Stream mapping to avoid building a large HTML String
                 AsyncResponseStream* stream = request->beginResponseStream(txt_html_charset, buffer_size);
-#ifdef DEBUG                
+#ifdef DEBUG
                 Serial.printf("Serving /mapping heap=%u webreq_cnt=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt);
 #endif                
                 stream->addHeader(hdr_cache_control_key, hdr_cache_control_val);
@@ -1317,11 +1311,11 @@ void init_webserver() {
               { 
                 webreq_enter();
                 request->onDisconnect([](){ webreq_exit(); });
-#ifdef DEBUG              
+#ifdef DEBUG
                 Serial.printf("Serving /state heap=%u webreq_cnt=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt);
 #endif
                 // Stream JSON directly to avoid DynamicJsonDocument/String allocations
-                AsyncResponseStream* stream = request->beginResponseStream(F("application/json; charset=UTF-8"), 256);
+                AsyncResponseStream* stream = request->beginResponseStream(F("application/json; charset=UTF-8"), buffer_size);
                 stream->addHeader(hdr_cache_control_key, hdr_cache_control_val);
                 stream->addHeader(hdr_connection_key, hdr_connection_val);
                 streamStateJSON(*stream);
@@ -1416,6 +1410,7 @@ void setup()
   Serial.print(F("Initializing SD card..."));
   activateSD();
   Serial.println(F("SD initialization done."));
+  buildSystemPathsOnce();
 
   // Seed RNG for shuffle mode
 #if defined(ESP32)
@@ -1433,10 +1428,11 @@ void setup()
 
   rootNode.buildDirectoryTree("/");
   rootNode.printDirectoryTree();
+  Serial.printf("Heap after dir tree: %u\n", (unsigned)xPortGetFreeHeapSize());
 
-  readDataFromFile(getSysDir(mapping_file));
+  readDataFromFile(PATH_MAPPING);
 
-  String progressPath = getSysDir(progress_file);
+  String progressPath = PATH_PROGRESS;
 
   continuePlaying = config.startAtStoredProgress && readSongProgress(progressPath.c_str());
 
@@ -1471,8 +1467,8 @@ void setup()
   audio.setVolume(config.initialVolume); // Use config value
   volume = config.initialVolume;         // Update global volume variable
 
-  // Optimize audio buffer size to save memory (ESP32-audioI2S optimization)
+  // Optimize audio buffer size to save heap (lower = less RAM, but risk of underflow on high bitrates)
-  audio.setBufferSize(8192); // Reduced from default large buffer (saves 40-600KB!)
+  audio.setBufferSize(8000);
 
   Serial.println(F("Audio init"));
 
@@ -1499,8 +1495,11 @@ void setup()
 
   if (wifiManager.autoConnect("HannaBox"))
   {
+    Serial.printf("Heap before init_webserver: %u\n", (unsigned)xPortGetFreeHeapSize());
     init_webserver();
+    Serial.printf("Heap before server.begin: %u\n", (unsigned)xPortGetFreeHeapSize());
     server.begin();
+    Serial.printf("Heap after server.begin: %u\n", (unsigned)xPortGetFreeHeapSize());
     Serial.println(F("Wifi init"));
   }
   else
@@ -1514,7 +1513,7 @@ void setup()
   xTaskCreatePinnedToCore(
       loop2,      /* Function to implement the task */
       "RFIDTask", /* Name of the task */
-      4096,       /* Stack size in words - reduced from 10000 to 4096 (optimization 2) */
+      2048,       /* Stack size in words - reduced from 4096 to 2048 to free heap */
       NULL,       /* Task input parameter */
       0,          /* Priority of the task */
       &RfidTask,  /* Task handle. */
@@ -1577,25 +1576,15 @@ void volume_action(AsyncWebServerRequest *request)
   request->send_P(200, txt_plain, PSTR("ok"));
 }
 
-const String getSysDir(const String filename)
-{
-  String st_sys_str(96);
-  st_sys_str.clear();
-  st_sys_str.concat("/");
-  st_sys_str.concat(sys_dir);
-  st_sys_str.concat("/");
-  st_sys_str.concat(filename);
-  return st_sys_str;
-}
 
 void loop()
 {
   if (webreq_cnt > 0 && webrequest_blockings > MAX_WEBREQUEST_BLOCKINGS) {
-    Serial.println(F("excessive webrequest blocking - suppress reset"));
+    if (!server_reset_pending) {
-    // Avoid resetting server mid-response to prevent mixing headers/body or truncation
+      Serial.println(F("excessive webrequest blocking - scheduling server reset"));
-    server.reset();
+      server_reset_pending = true;
-    init_webserver();
+    }
-    webreq_cnt = 0;
+    // reset the counter to avoid repeated scheduling while still busy
     webrequest_blockings = 0;
   }
 
@@ -1638,7 +1627,7 @@ void loop()
   else if (!startupSoundPlayed)
   {
     startupSoundPlayed = true;
-    playSongByPath(getSysDir(startup_sound));
+    playSongByPath(PATH_STARTUP);
   }
 
   // send device to sleep:
@@ -1650,18 +1639,12 @@ void loop()
     prepareSleepMode = true;
     if (currentNode != nullptr)
     {
-      static String progressPath = "";
-      if (progressPath.isEmpty()) {
-        progressPath = getSysDir(progress_file);
-      }
-      
-      
       deactivateRFID();
       activateSD();
-      writeSongProgress(progressPath.c_str(), currentNode->getCurrentPlayingId(), currentNode->getSecondsPlayed());
+      writeSongProgress(PATH_PROGRESS.c_str(), currentNode->getCurrentPlayingId(), currentNode->getSecondsPlayed());
     }
 
-    playSongByPath(getSysDir(sleep_sound));
+    playSongByPath(PATH_SLEEP);
   }
 
   if (now - lastInteraction > config.sleepDelay)
@@ -1708,7 +1691,7 @@ void loop()
         }
         audio.setVolume(vol);
         volume = vol;
-        playSongByPath(getSysDir(startup_sound));
+        playSongByPath(PATH_STARTUP);
       }
     }
   }
@@ -1743,7 +1726,7 @@ void loop()
         }
         audio.setVolume(vol);
         volume = vol;
-        playSongByPath(getSysDir(startup_sound));
+        playSongByPath(PATH_STARTUP);
       }
     }
   }
@@ -1793,6 +1776,15 @@ void loop()
     webrequest_blockings = 0;
   }
 
+  // Perform deferred server reset when no active requests to avoid AsyncTCP stack corruption
+  if (server_reset_pending && webreq_cnt == 0) {
+    Serial.println(F("performing deferred server reset"));
+    server.reset();
+    init_webserver();
+    server.begin();
+    server_reset_pending = false;
+  }
+
   loopCounter++;
   vTaskDelay(1);
 

src/main.h

@@ -88,6 +88,7 @@ bool RFIDActive = false;
 volatile uint32_t webreq_cnt = 0;
 static inline void webreq_enter() { __sync_add_and_fetch(&webreq_cnt, 1); }
 static inline void webreq_exit()  { __sync_sub_and_fetch(&webreq_cnt, 1); }
+volatile bool server_reset_pending = false;
 
 uint16_t voltage_threshold_counter = 0;
 
@@ -111,7 +112,6 @@ void init_webserver();
 
 boolean buttonPressed(const uint8_t pin);
 
-const String getSysDir(const String filename);
 
 /**
  * Helper routine to dump a byte array as hex values to Serial.