[ai] further memory optimizations

platformio.ini

@@ -20,8 +20,9 @@ lib_deps =
 	bblanchon/ArduinoJson@^6.21.3
 monitor_speed = 115200
 build_flags = 
-    -Os                                    ; Optimize for size
+    -Os                                   ; Optimize for size
- ;   -DCORE_DEBUG_LEVEL=0                  ; Disable all debug output
+;    -DDEBUG                          ; Hannabox Debugging
+    -DCORE_DEBUG_LEVEL=0                 ; Disable all debug output
     -DARDUINO_LOOP_STACK_SIZE=3072        ; Further reduce from 4096
     -DWIFI_TASK_STACK_SIZE=3072           ; Reduce WiFi task stack
     -DARDUINO_EVENT_TASK_STACK_SIZE=2048  ; Reduce event task stack

src/DirectoryNode.cpp

@@ -37,12 +37,42 @@ const std::vector<String> &DirectoryNode::getMP3Files() const
     return mp3Files;
 }
 
+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
+{
+    if (dirPath == "/")
+    {
+        String p = "/";
+        p += fileName;
+        return p;
+    }
+    String p = dirPath;
+    p += "/";
+    p += fileName;
+    return p;
+}
+
 void DirectoryNode::setCurrentPlaying(const String &mp3File)
 {
-    currentPlaying = mp3File;
+    bool isAbs = (mp3File.length() > 0) && (mp3File.charAt(0) == '/');
+    const String &fileName = isAbs ? mp3File.substring(mp3File.lastIndexOf('/') + 1) : mp3File;
+    currentPlaying = isAbs ? mp3File : buildFullPath(fileName);
     for (size_t i = 0; i < mp3Files.size(); i++)
     {
-        if (mp3Files[i] == mp3File && ids.size() > i)
+        if (mp3Files[i] == fileName && ids.size() > i)
         {
             currentPlayingId = ids[i];
             break;
@@ -102,6 +132,14 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
     mp3Files.shrink_to_fit();
     ids.shrink_to_fit();
 
+    // Set directory path for this node (normalize: keep "/" or remove trailing slash)
+    String path = String(currentPath);
+    if (path.length() > 1 && path.endsWith("/"))
+    {
+        path.remove(path.length() - 1);
+    }
+    dirPath = path;
+
     // First collect entries so we can sort them alphabetically
     std::vector<String> dirNames;
     std::vector<String> fileNames;
@@ -167,15 +205,10 @@ void DirectoryNode::buildDirectoryTree(const char *currentPath)
         newNode->buildDirectoryTree(childPath.c_str());
     }
 
-    // Add MP3 files in alphabetical order
+    // Add MP3 files in alphabetical order (store only filenames; build full paths on demand)
     for (const String &fileName : fileNames)
     {
-        String fullPath = String(currentPath);
+        mp3Files.push_back(fileName);
-        if (!fullPath.endsWith("/"))
-            fullPath += "/";
-        fullPath += fileName;
-
-        mp3Files.push_back(std::move(fullPath));
         ids.push_back(getNextId());
     }
 }
@@ -194,7 +227,7 @@ void DirectoryNode::printDirectoryTree(int level) const
         {
             Serial.print(F("  "));
         }
-        Serial.println(mp3File);
+        Serial.println(buildFullPath(mp3File));
     }
 
     for (DirectoryNode *childNode : subdirectories)
@@ -241,7 +274,7 @@ DirectoryNode *DirectoryNode::advanceToMP3(const uint16_t id)
         if (id == ids[i])
         {
             // Found the current MP3 file
-            currentPlaying = mp3Files[i];
+            currentPlaying = buildFullPath(mp3Files[i]);
             currentPlayingId = id;
             return this;
         }
@@ -296,7 +329,7 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String &songName)
     {
         if (isAbsolutePath)
         {
-            if (mp3Files[i].equalsIgnoreCase(songName))
+            if (buildFullPath(mp3Files[i]).equalsIgnoreCase(songName))
             {
                 setCurrentPlaying(mp3Files[i]);
                 return this;
@@ -317,13 +350,10 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String &songName)
     // Then search in subdirectories
     for (auto subdir : subdirectories)
     {
-        // Absolute folder target: match directory by its full path derived from its files
+        // Absolute folder target: match directory by its full path (dirPath)
-        if (isAbsolutePath && subdir->mp3Files.size() > 0)
+        if (isAbsolutePath)
         {
-            String anyFile = subdir->mp3Files[0];
+            if (subdir->getDirPath().equalsIgnoreCase(normalizedPath))
-            int lastSlash = anyFile.lastIndexOf('/');
-            String subdirPath = (lastSlash >= 0) ? anyFile.substring(0, lastSlash) : String();
-            if (subdirPath.equalsIgnoreCase(normalizedPath))
             {
                 subdir->advanceToFirstMP3InThisNode();
                 return subdir;
@@ -342,7 +372,7 @@ DirectoryNode *DirectoryNode::advanceToMP3(const String &songName)
 
             if (isAbsolutePath)
             {
-                if (subdir->mp3Files[i].equalsIgnoreCase(songName))
+                if (subdir->buildFullPath(subdir->mp3Files[i]).equalsIgnoreCase(songName))
                 {
                     subdir->setCurrentPlaying(subdir->mp3Files[i]);
                     return subdir;
@@ -401,7 +431,7 @@ DirectoryNode *DirectoryNode::goToPreviousMP3(uint32_t thresholdSeconds)
     int currentIndex = -1;
     for (size_t i = 0; i < mp3Files.size(); i++)
     {
-        if (currentPlaying == mp3Files[i])
+        if (currentPlaying == buildFullPath(mp3Files[i]))
         {
             currentIndex = i;
             break;
@@ -412,7 +442,7 @@ DirectoryNode *DirectoryNode::goToPreviousMP3(uint32_t thresholdSeconds)
     if (currentIndex > 0)
     {
         Serial.print(F("goToPreviousMP3: Moving to previous song in same directory: "));
-        Serial.println(mp3Files[currentIndex - 1]);
+        Serial.println(buildFullPath(mp3Files[currentIndex - 1]));
         setCurrentPlaying(mp3Files[currentIndex - 1]);
         return this;
     }
@@ -441,7 +471,7 @@ DirectoryNode *DirectoryNode::findPreviousMP3Globally(const String &currentGloba
     {
         DirectoryNode *node = allMP3s[i].first;
         int fileIndex = allMP3s[i].second;
-        if (node->mp3Files[fileIndex] == currentGlobal)
+        if (node->buildFullPath(node->mp3Files[fileIndex]) == currentGlobal)
         {
             currentGlobalIndex = i;
             break;
@@ -455,7 +485,7 @@ DirectoryNode *DirectoryNode::findPreviousMP3Globally(const String &currentGloba
         int prevFileIndex = allMP3s[currentGlobalIndex - 1].second;
 
         Serial.print(F("findPreviousMP3Globally: Moving to previous song globally: "));
-        Serial.println(prevNode->mp3Files[prevFileIndex]);
+        Serial.println(prevNode->buildFullPath(prevNode->mp3Files[prevFileIndex]));
 
         prevNode->setCurrentPlaying(prevNode->mp3Files[prevFileIndex]);
         return prevNode;
@@ -495,7 +525,7 @@ DirectoryNode *DirectoryNode::advanceToNextMP3(const String &currentGlobal)
     {
         for (size_t i = 0; i < mp3Files.size(); i++)
         {
-            if (currentGlobal == mp3Files[i])
+            if (currentGlobal == buildFullPath(mp3Files[i]))
             {
                 // Found the current playing MP3 file
                 if (i < mp3Files.size() - 1)
@@ -525,7 +555,7 @@ 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->mp3Files[i])
+            if (currentGlobal == subdir->buildFullPath(subdir->mp3Files[i]))
             {
                 // Found the current playing MP3 file
                 if (i < subdir->mp3Files.size() - 1)
@@ -573,10 +603,10 @@ void DirectoryNode::streamDirectoryHTML(Print &out) const {
         out.print(F("<li data-id=\""));
         out.print(ids[i]);
         out.print(F("\">"));
-        out.print(mp3Files[i]);
+        out.print(buildFullPath(mp3Files[i]));
         out.println(F("</li>"));
 #ifdef DEBUG        
-        Serial.printf("stream song: %s\n",mp3Files[i].c_str());
+        Serial.printf("stream song: %s\n", buildFullPath(mp3Files[i]).c_str());
 #endif        
         // Yield every few items to allow the async web server to send buffered data
         if (i % 5 == 4) {

src/DirectoryNode.h

@@ -14,6 +14,7 @@ class DirectoryNode {
 private:
   uint16_t id;
   String name;
+  String dirPath;
   std::vector<DirectoryNode*> subdirectories;
   std::vector<String> mp3Files;
   std::vector<uint16_t> ids;
@@ -21,6 +22,7 @@ private:
   uint16_t currentPlayingId = 0;
   uint16_t secondsPlayed = 0;
   
+  String buildFullPath(const String& fileName) const;
    
 
 public:
@@ -33,6 +35,8 @@ public:
   const uint16_t getId() const;
   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;
 
 
 /*

src/main.cpp

@@ -6,7 +6,6 @@
 
 #include <ESPAsyncWebServer.h>   //Local WebServer used to serve the configuration portal
 #include <ESPAsyncWiFiManager.h> //https://github.com/tzapu/WiFiManager WiFi Configuration Magic
-#include <ArduinoJson.h>
 
 #include "Audio.h"
 
@@ -682,36 +681,6 @@ boolean readSongProgress(const char *filename)
   return true;
 }
 
-String getState()
-{
-  // Use static buffer to avoid repeated allocations
-  static DynamicJsonDocument jsonState(512);
-  static String output;
-
-  output.clear();
-  output.reserve(512); // Pre-allocate string buffer
-  
-  jsonState["playing"] = audio.isRunning();
-
-  if (currentNode != nullptr && !currentNode->getCurrentPlaying().isEmpty())
-    jsonState["title"] = currentNode->getCurrentPlaying();
-  else
-    jsonState["title"] = "Stopped";
-  jsonState["filepath"] = currentNode->getCurrentPlaying();
-
-
-  jsonState["time"] = audio.getAudioCurrentTime();
-  jsonState["volume"] = audio.getVolume();
-  jsonState["length"] = audio.getAudioFileDuration();
-  jsonState["voltage"] = lastVoltage;
-  jsonState["uid"] = lastUid;
-  jsonState["heap"] = free_heap;
-
-  serializeJson(jsonState, output);
-  jsonState.clear();
-
-  return output;
-}
 
 // Function to save the rfid_map to the mapping file
 void saveMappingToFile(const String filename)
@@ -863,6 +832,113 @@ String processor(const String &var)
   return String(); // Return empty string instead of creating new String
 }
 
+// Memory-optimized helpers and streamers to avoid large temporary Strings
+
+static inline void htmlEscapeAndPrint(Print &out, const String &s)
+{
+  for (size_t i = 0; i < s.length(); ++i)
+  {
+    char c = s[i];
+    switch (c)
+    {
+      case '&': out.print(F("&"));  break;
+      case '<':  out.print(F("<"));   break;
+      case '>':  out.print(F(">"));   break;
+      case '\"':    out.print(F("\"")); break;
+      case '\'':    out.print(F("&#39;"));  break;
+      default:      out.print(c);           break;
+    }
+  }
+}
+
+static inline void jsonEscapeAndPrint(Print &out, const String &s)
+{
+  for (size_t i = 0; i < s.length(); ++i)
+  {
+    char c = s[i];
+    switch (c)
+    {
+    case '\"': out.print(F("\\\"")); break;
+    case '\\': out.print(F("\\\\")); break;
+    case '\b': out.print(F("\\b"));  break;
+    case '\f': out.print(F("\\f"));  break;
+    case '\n': out.print(F("\\n"));  break;
+    case '\r': out.print(F("\\r"));  break;
+    case '\t': out.print(F("\\t"));  break;
+    default:
+      if ((uint8_t)c < 0x20) { // control chars as \u00XX
+        out.print(F("\\u00"));
+        const char hex[] = "0123456789ABCDEF";
+        out.print(hex[(c >> 4) & 0x0F]);
+        out.print(hex[c & 0x0F]);
+      } else {
+        out.print(c);
+      }
+      break;
+    }
+  }
+}
+
+static void streamMappingHTML(Print &out)
+{
+  out.print(F("<table style='width:100%;border-collapse:collapse;'><tr><th style='border:1px solid #ccc;padding:4px;'>RFID</th><th style='border:1px solid #ccc;padding:4px;'>Song</th></tr>"));
+  for (const auto &pair : rfid_map)
+  {
+    out.print(F("<tr><td style='border:1px solid #ccc;padding:4px;'>"));
+    htmlEscapeAndPrint(out, pair.first);
+    out.print(F("</td><td style='border:1px solid #ccc;padding:4px;'>"));
+    // target|mode
+    htmlEscapeAndPrint(out, pair.second.target);
+    out.print(F("|"));
+    out.print(pair.second.mode);
+    out.print(F("</td></tr>"));
+    // Yield occasionally if async server is buffering
+    yield();
+  }
+  out.print(F("</table>"));
+}
+
+static void streamStateJSON(Print &out)
+{
+  const bool isRunning = audio.isRunning();
+  static const String emptyStr;
+  const String &current =
+      (currentNode != nullptr) ? currentNode->getCurrentPlaying() : emptyStr;
+
+  out.print(F("{\"playing\":"));
+  out.print(isRunning ? F("true") : F("false"));
+
+  out.print(F(",\"title\":\""));
+  if (!current.isEmpty()) jsonEscapeAndPrint(out, current);
+  else out.print(F("Stopped"));
+  out.print(F("\""));
+
+  out.print(F(",\"filepath\":\""));
+  jsonEscapeAndPrint(out, current);
+  out.print(F("\""));
+
+  out.print(F(",\"time\":"));
+  out.print(audio.getAudioCurrentTime());
+
+  out.print(F(",\"volume\":"));
+  out.print(audio.getVolume());
+
+  out.print(F(",\"length\":"));
+  out.print(audio.getAudioFileDuration());
+
+  out.print(F(",\"voltage\":"));
+  out.print(lastVoltage);
+
+  out.print(F(",\"uid\":\""));
+  jsonEscapeAndPrint(out, lastUid);
+  out.print(F("\""));
+
+  out.print(F(",\"heap\":"));
+  out.print(free_heap);
+
+  out.print(F("}"));
+}
+
 void stop()
 {
   if (audio.isRunning())
@@ -1132,7 +1208,7 @@ static void serveStaticFile(AsyncWebServerRequest *request,
     auto resp = request->beginChunkedResponse(contentType,
                   [ctx](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
                     size_t toRead = maxLen;
-                    if (toRead > 512) toRead = 512;
+                    if (toRead > buffer_size) toRead = buffer_size;
                     sd_lock_acquire();
                     size_t n = ctx->f.read(buffer, toRead);
                     sd_lock_release();
@@ -1217,32 +1293,32 @@ void init_webserver() {
               {
                 webreq_enter();
                 request->onDisconnect([](){ webreq_exit();});
-                // Stream mapping to avoid Content-Length mismatches and reduce heap spikes
+                // Stream mapping to avoid building a large HTML String
                 AsyncResponseStream* stream = request->beginResponseStream(txt_html_charset, 512);
 #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);
                 stream->addHeader(hdr_connection_key, hdr_connection_val);
-                String html = processor(String("MAPPING"));
+                streamMappingHTML(*stream);
-                stream->print(html);
                 request->send(stream);
               });
 
 
     server.on("/state", HTTP_GET, [](AsyncWebServerRequest *request)
               { 
-              webreq_enter();
+                webreq_enter();
-              request->onDisconnect([](){ webreq_exit(); });
+                request->onDisconnect([](){ webreq_exit(); });
-              String state = getState();
 #ifdef DEBUG              
-              Serial.printf("Serving /state heap=%u webreq_cnt=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt);
+                Serial.printf("Serving /state heap=%u webreq_cnt=%u\n", (unsigned)xPortGetFreeHeapSize(), (unsigned)webreq_cnt);
 #endif
-
+                // Stream JSON directly to avoid DynamicJsonDocument/String allocations
-              AsyncWebServerResponse* resp = request->beginResponse(200, F("application/json; charset=UTF-8"), state);
+                AsyncResponseStream* stream = request->beginResponseStream(F("application/json; charset=UTF-8"), 256);
-              resp->addHeader(hdr_cache_control_key, hdr_cache_control_val);
+                stream->addHeader(hdr_cache_control_key, hdr_cache_control_val);
-              resp->addHeader(hdr_connection_key, hdr_connection_val);
+                stream->addHeader(hdr_connection_key, hdr_connection_val);
-              request->send(resp); });
+                streamStateJSON(*stream);
+                request->send(stream);
+              });
 
     server.on("/start", HTTP_GET, [](AsyncWebServerRequest *request)
               {
@@ -1509,6 +1585,8 @@ void loop()
   if (webreq_cnt > 0 && webrequest_blockings > MAX_WEBREQUEST_BLOCKINGS) {
     Serial.println(F("excessive webrequest blocking - suppress reset"));
     // Avoid resetting server mid-response to prevent mixing headers/body or truncation
+    server.reset();
+    init_webserver();
     webreq_cnt = 0;
     webrequest_blockings = 0;
   }

src/main.h

@@ -34,8 +34,6 @@
 
 #define MAX_VOL 15
 
-//#define DEBUG TRUE
-
 File root;
 File mp3File;