Description
This is my code. It's an operation that I read a configuration file then rewrite it with a new config.
#include <ArduinoJson.h>
#include <LittleFS.h>
bool loadConfig(StaticJsonDocument<200> &doc)
{
File configFile = LittleFS.open("/config.json", "r");
if (!configFile)
{
Serial.println("Failed to open config file");
clearFile(configFile);
return false;
}
size_t size = configFile.size();
if (size > 1024)
{
Serial.println("Config file size is too large");
clearFile(configFile);
return false;
}
std::unique_ptr<char[]> buf(new char[size]);
configFile.readBytes(buf.get(), size);
auto error = deserializeJson(doc, buf.get());
if (error)
{
Serial.println("Failed to parse config file");
clearFile(configFile);
return false;
}
clearFile(configFile);
return true;
}
bool saveConfig(bool load)
{
StaticJsonDocument<200> doc;
if(load){
loadConfig(doc);
}
Serial.println("after load config");
serializeJson(doc, Serial);
Serial.println();
File configFile = LittleFS.open("/config.json", "w");
Serial.println("after load file");
serializeJson(doc, Serial);
Serial.println();
doc["serverName"] = "api.example.com";
doc["accessToken"] = "something";
Serial.println("after change config");
serializeJson(doc, Serial);
Serial.println();
if (!configFile)
{
Serial.println("Failed to open config file for writing");
clearFile(configFile);
return false;
}
serializeJson(doc, configFile);
clearFile(configFile);
Serial.println();
return true;
}
void clearFile(File &file){
file.close();
}
void setup()
{
Serial.begin(115200);
Serial.println("");
delay(1000);
Serial.println("Mounting FS...");
if (!LittleFS.begin())
{
Serial.println("Failed to mount file system");
return;
}
saveConfig(false);
}
void loop()
{
saveConfig(true);
delay(5000);
}And this is a part of output from serial
after load config
null
after load file
null
after change config
{"serverName":"api.example.com","accessToken":"something"}
after load config
{"serverName":"api.example.com","accessToken":"something"}
after load file
{"":"api.example.
5B02
com","accessToken":"something"}
after change config
{"":"api.example.com","accessToken":"something","serverName":"api.example.com"}
after load config
{"":"api.example.com","accessToken":"something","serverName":"api.example.com"}
after load file
{"":"","accessToken":"something","serverName":"api.example.com"}
after change config
{"":"","accessToken":"something","serverName":"api.example.com"}
Form the output informations, we can see that the value from the json document was changed without reason. I was wondering if I am wrong and how I can fix the problem. Thanks~❤