ESP32_ChinaDieselHeater_Con.../lib/ArduinoJson/examples/JsonConfigFile/JsonConfigFile.ino

144 lines
4.1 KiB
C++

// ArduinoJson - arduinojson.org
// Copyright Benoit Blanchon 2014-2018
// MIT License
//
// This example shows how to store your project configuration in a file.
// It uses the SD library but can be easily modified for any other file-system.
//
// The file contains a JSON document with the following content:
// {
// "hostname": "examples.com",
// "port": 2731
// }
#include <ArduinoJson.h>
#include <SD.h>
#include <SPI.h>
// Configuration that we'll store on disk
struct Config {
char hostname[64];
int port;
};
const char *filename = "/config.txt"; // <- SD library uses 8.3 filenames
Config config; // <- global configuration object
// Loads the configuration from a file
void loadConfiguration(const char *filename, Config &config) {
// Open file for reading
File file = SD.open(filename);
// Allocate the memory pool on the stack.
// Don't forget to change the capacity to match your JSON document.
// Use arduinojson.org/assistant to compute the capacity.
StaticJsonBuffer<512> jsonBuffer;
// Parse the root object
JsonObject &root = jsonBuffer.parseObject(file);
if (!root.success())
Serial.println(F("Failed to read file, using default configuration"));
// Copy values from the JsonObject to the Config
config.port = root["port"] | 2731;
strlcpy(config.hostname, // <- destination
root["hostname"] | "example.com", // <- source
sizeof(config.hostname)); // <- destination's capacity
// Close the file (File's destructor doesn't close the file)
file.close();
}
// Saves the configuration to a file
void saveConfiguration(const char *filename, const Config &config) {
// Delete existing file, otherwise the configuration is appended to the file
SD.remove(filename);
// Open file for writing
File file = SD.open(filename, FILE_WRITE);
if (!file) {
Serial.println(F("Failed to create file"));
return;
}
// Allocate the memory pool on the stack
// Don't forget to change the capacity to match your JSON document.
// Use https://arduinojson.org/assistant/ to compute the capacity.
StaticJsonBuffer<256> jsonBuffer;
// Parse the root object
JsonObject &root = jsonBuffer.createObject();
// Set the values
root["hostname"] = config.hostname;
root["port"] = config.port;
// Serialize JSON to file
if (root.printTo(file) == 0) {
Serial.println(F("Failed to write to file"));
}
// Close the file (File's destructor doesn't close the file)
file.close();
}
// Prints the content of a file to the Serial
void printFile(const char *filename) {
// Open file for reading
File file = SD.open(filename);
if (!file) {
Serial.println(F("Failed to read file"));
return;
}
// Extract each characters by one by one
while (file.available()) {
Serial.print((char)file.read());
}
Serial.println();
// Close the file (File's destructor doesn't close the file)
file.close();
}
void setup() {
// Initialize serial port
Serial.begin(9600);
while (!Serial) continue;
// Initialize SD library
while (!SD.begin()) {
Serial.println(F("Failed to initialize SD library"));
delay(1000);
}
// Should load default config if run for the first time
Serial.println(F("Loading configuration..."));
loadConfiguration(filename, config);
// Create configuration file
Serial.println(F("Saving configuration..."));
saveConfiguration(filename, config);
// Dump config file
Serial.println(F("Print config file..."));
printFile(filename);
}
void loop() {
// not used in this example
}
// See also
// --------
//
// https://arduinojson.org/ contains the documentation for all the functions
// used above. It also includes an FAQ that will help you solve any
// serialization or deserialization problem.
//
// The book "Mastering ArduinoJson" contains a case study of a project that has
// a complex configuration with nested members.
// Contrary to this example, the project in the book uses the SPIFFS filesystem.
// Learn more at https://arduinojson.org/book/
// Use the coupon code TWENTY for a 20% discount ❤❤❤❤❤