How to parse JSON

This is the information for everyone who wants to create, modify and parse JSON with the built-in JSON maker and parser without external JSON library.

This library introduces the 3 classes i.e. FirebaseJson, FirebaseJsonArray and FirebaseJsonData for creating, edit and parse JSON data.

FirebaseJson represents the JSON object, FirebaseJsonArray is for the JSON array, and FirebaseJsonData stores the parse information when you want to parse (extract) the data from JSON object or JSON array.

In setup() you may need to set the buffer size to handle large JSON payload data...

//Set the size of WiFi rx/tx buffers in the case where we want to work with large data.```
//Set any value from 512 to 16384```
firebaseData.setBSSLBufferSize(1024, 1024);```

//Set the size of HTTP response buffers in the case where we want to work with large data.```
firebaseData.setResponseSize(1024);```

Here get JSON from Firebase and parse it.

Assume that we want to parse the JSON at node /Data/sensors

if (Firebase.getJSON(firebaseData, "/Data/sensors")) {

  //FirebaseJson object that returned from getJson
  FirebaseJson &json = firebaseData.jsonObject();

  //temporary object to store the data from parsing
  //this will be reused over and over
  FirebaseJsonData data;

  //parse data by key or path, the result is in FirebaseJsonData object
  json.get(data, "/path/to/node");

  //or parse the complex nested atrray in nested object
  //json.get(data, "/path/to/node/[0]/[3]"); //Where [0] is index 0, [3] is index 3

  //parsing ok?
  if (data.success) {
    
    //We determine the type of value from parsing, you can get the string by using **data.stringValue** of all data types.
    if (data.typeNum == JSON_INT) // or data.type == "int"
      Serial.println(data.intValue);
    else if (data.typeNum == JSON_BOOL) //or data.type == "bool"
      Serial.println(data.boolValue);
    else if (data.typeNum == JSON_DOUBLE) //or data.type == "double"
      Serial.println(data.doubleValue);
    else if (data.typeNum == JSON_STRING ||  data.typeNum == JSON_NULL) //or data.type == "string" || data.type == "null"
      Serial.println(data.stringValue);
    else if (data.typeNum == JSON_ARRAY) //or data.type == "array"
    {

      //get the FirebaseJson array object
      FirebaseJsonArray myArr;
      data.getArray(myArr);
      for (size_t i = 0; i < myArr.size(); i++)
      {
        //get array data at index
        myArr.get(data, i);

        //or parse JSON object or JSON array in Array
        //myArr.get(data, "/any_child/another_child/another_one");

        //parsing success?
        if (data.success) {

          if (data.typeNum == JSON_INT)
            Serial.println(data.intValue);
          else if (data.typeNum == JSON_BOOL)
            Serial.println(data.boolValue);
          else if (data.typeNum == JSON_DOUBLE)
            Serial.println(data.doubleValue);
          else if (data.typeNum == JSON_STRING )
            Serial.println(data.stringValue);
          else if (data.typeNum == JSON_ARRAY)
          {
            //parse array in array
          }
          else if (data.typeNum == JSON_OBJECT)
          {
            //parse JSON object in array
          }
        }

      } else if (data.typeNum == JSON_OBJECT) //or data.type == "object"
      {
        //parse the nested JSON object here

        FirebaseJsonA json2;
        data.getJSON(json2);
        //parse it
        json2.get(data, "/another/path/to/node");
        Serial.println(data.stringValue);

      }
    }

  }
}