Dump settings line by line to prevent memory issues (#896)

code/espurna/settings.ino

@@ -38,7 +38,7 @@ unsigned long settingsSize() {
 
 // -----------------------------------------------------------------------------
 
-unsigned int _settingsKeyCount() {
+unsigned int settingsKeyCount() {
     unsigned count = 0;
     unsigned pos = SPI_FLASH_SEC_SIZE - 1;
     while (size_t len = EEPROMr.read(pos)) {
@@ -50,7 +50,7 @@ unsigned int _settingsKeyCount() {
     return count;
 }
 
-String _settingsKeyName(unsigned int index) {
+String settingsKeyName(unsigned int index) {
 
     String s;
 
@@ -80,11 +80,11 @@ std::vector<String> _settingsKeys() {
     std::vector<String> keys;
 
     //unsigned int size = settingsKeyCount();
-    unsigned int size = _settingsKeyCount();
+    unsigned int size = settingsKeyCount();
     for (unsigned int i=0; i<size; i++) {
 
         //String key = settingsKeyName(i);
-        String key = _settingsKeyName(i);
+        String key = settingsKeyName(i);
         bool inserted = false;
         for (unsigned char j=0; j<keys.size(); j++) {
 
@@ -277,7 +277,7 @@ void _settingsInitCommands() {
             DEBUG_MSG_P(PSTR("+OK\n"));
         });
     #endif
-    
+
     settingsRegisterCommand(F("RESET"), [](Embedis* e) {
         DEBUG_MSG_P(PSTR("+OK\n"));
         deferredReset(100, CUSTOM_RESET_TERMINAL);

code/espurna/web.ino

@@ -67,20 +67,24 @@ void _onGetConfig(AsyncWebServerRequest *request) {
 
     AsyncResponseStream *response = request->beginResponseStream("text/json");
 
-    DynamicJsonBuffer jsonBuffer;
-    JsonObject &root = jsonBuffer.createObject();
-    root["app"] = APP_NAME;
-    root["version"] = APP_VERSION;
-    settingsGetJson(root);
-    root.prettyPrintTo(*response);
-    jsonBuffer.clear();
-
     char buffer[100];
     snprintf_P(buffer, sizeof(buffer), PSTR("attachment; filename=\"%s-backup.json\""), (char *) getSetting("hostname").c_str());
     response->addHeader("Content-Disposition", buffer);
     response->addHeader("X-XSS-Protection", "1; mode=block");
     response->addHeader("X-Content-Type-Options", "nosniff");
     response->addHeader("X-Frame-Options", "deny");
+
+    response->printf("{\n  \"app\": \"%s\",\n  \"version\": \"%s\"", APP_NAME, APP_VERSION);
+
+    // Write the keys line by line (not sorted)
+    unsigned long count = settingsKeyCount();
+    for (unsigned int i=0; i<count; i++) {
+        String key = settingsKeyName(i);
+        String value = getSetting(key);
+        response->printf(",\n  \"%s\": \"%s\"", key.c_str(), value.c_str());
+    }
+    response->printf("\n}");
+
     request->send(response);
 
 }