The new class for DynamicJsonDocument

src/utils/DynamicJsonHandler.cpp

@@ -0,0 +1,39 @@
+#include "DynamicJsonHandler.h"
+
+DynamicJsonHandler::DynamicJsonHandler() : doc(min_size) {
+}
+
+DynamicJsonHandler::~DynamicJsonHandler() {
+    delete &doc;
+}
+
+String DynamicJsonHandler::toString() {
+    String jsonString;
+    serializeJson(doc, jsonString);
+    doc.clear(); // TODO: Entfernen wegen mqtt + webserial?
+    return jsonString;
+}
+
+void DynamicJsonHandler::clear() {
+    doc.clear();
+}
+
+size_t DynamicJsonHandler::size() const {
+    return doc.memoryUsage();
+}
+
+void DynamicJsonHandler::resizeDocument(size_t requiredSize) {
+    // TODO: multiplikator zwei muss ersetzt werden? Kann noch minimal werden.
+    size_t newCapacity = min(max(requiredSize * 2, min_size), max_size);
+    DynamicJsonDocument newDoc(newCapacity);
+    newDoc.set(doc); // Bestehende Daten kopieren
+    doc = std::move(newDoc);
+}
+
+size_t DynamicJsonHandler::min(size_t a, size_t b) {
+    return (a < b) ? a : b;
+}
+
+size_t DynamicJsonHandler::max(size_t a, size_t b) {
+    return (a > b) ? a : b;
+}

src/utils/DynamicJsonHandler.h

@@ -0,0 +1,44 @@
+//-----------------------------------------------------------------------------
+// 2022 Ahoy, https://github.com/lumpapu/ahoy
+// Creative Commons - http://creativecommons.org/licenses/by-nc-sa/3.0/de/
+//-----------------------------------------------------------------------------
+
+#ifndef __DYNAMICJSONHANDLER_H__
+#define __DYNAMICJSONHANDLER_H__
+
+#include <Arduino.h>
+#include <ArduinoJson.h>
+#include <string>
+
+class DynamicJsonHandler {
+public:
+    DynamicJsonHandler();
+    ~DynamicJsonHandler();
+
+    template<typename T>
+    void addProperty(const std::string& key, const T& value);
+
+    String toString();
+    void clear();
+    size_t size() const;
+
+private:
+    DynamicJsonDocument doc;
+    static const size_t min_size = 256;
+    static const size_t max_size = 5000; // Max RAM : 2 = da es für resizeDocument eng werden könnte?
+
+    void resizeDocument(size_t requiredSize);
+    size_t min(size_t a, size_t b);
+    size_t max(size_t a, size_t b);
+};
+
+template<typename T>
+void DynamicJsonHandler::addProperty(const std::string& key, const T& value) {
+    size_t additionalSize = JSON_OBJECT_SIZE(1) + key.length() + sizeof(value);
+    if (doc.memoryUsage() + additionalSize > doc.capacity()) {
+        resizeDocument(doc.memoryUsage() + additionalSize);
+    }
+    doc[key] = value;
+}
+
+#endif /*__DYNAMICJSONHANDLER_H__*/