PumpenSteuerung/lib/framework/FSPersistence.h

99 lines
2.9 KiB
C++

#ifndef FSPersistence_h
#define FSPersistence_h
#include <StatefulService.h>
#include <FS.h>
template <class T>
class FSPersistence {
public:
FSPersistence(JsonStateReader<T> stateReader,
JsonStateUpdater<T> stateUpdater,
StatefulService<T>* statefulService,
FS* fs,
const char* filePath,
size_t bufferSize = DEFAULT_BUFFER_SIZE) :
_stateReader(stateReader),
_stateUpdater(stateUpdater),
_statefulService(statefulService),
_fs(fs),
_filePath(filePath),
_bufferSize(bufferSize),
_updateHandlerId(0) {
enableUpdateHandler();
}
void readFromFS() {
File settingsFile = _fs->open(_filePath, "r");
if (settingsFile) {
DynamicJsonDocument jsonDocument = DynamicJsonDocument(_bufferSize);
DeserializationError error = deserializeJson(jsonDocument, settingsFile);
if (error == DeserializationError::Ok && jsonDocument.is<JsonObject>()) {
JsonObject jsonObject = jsonDocument.as<JsonObject>();
_statefulService->updateWithoutPropagation(jsonObject, _stateUpdater);
settingsFile.close();
return;
}
settingsFile.close();
}
// If we reach here we have not been successful in loading the config,
// hard-coded emergency defaults are now applied.
applyDefaults();
}
bool writeToFS() {
// create and populate a new json object
DynamicJsonDocument jsonDocument = DynamicJsonDocument(_bufferSize);
JsonObject jsonObject = jsonDocument.to<JsonObject>();
_statefulService->read(jsonObject, _stateReader);
// serialize it to filesystem
File settingsFile = _fs->open(_filePath, "w");
// failed to open file, return false
if (!settingsFile) {
return false;
}
// serialize the data to the file
serializeJson(jsonDocument, settingsFile);
settingsFile.close();
return true;
}
void disableUpdateHandler() {
if (_updateHandlerId) {
_statefulService->removeUpdateHandler(_updateHandlerId);
_updateHandlerId = 0;
}
}
void enableUpdateHandler() {
if (!_updateHandlerId) {
_updateHandlerId = _statefulService->addUpdateHandler([&](const String& originId) { writeToFS(); });
}
}
private:
JsonStateReader<T> _stateReader;
JsonStateUpdater<T> _stateUpdater;
StatefulService<T>* _statefulService;
FS* _fs;
const char* _filePath;
size_t _bufferSize;
update_handler_id_t _updateHandlerId;
protected:
// We assume the updater supplies sensible defaults if an empty object
// is supplied, this virtual function allows that to be changed.
virtual void applyDefaults() {
DynamicJsonDocument jsonDocument = DynamicJsonDocument(_bufferSize);
JsonObject jsonObject = jsonDocument.as<JsonObject>();
_statefulService->updateWithoutPropagation(jsonObject, _stateUpdater);
}
};
#endif // end FSPersistence