ESP32 and Firebase Integration: Retrieving JSON Object from Realtime Database

[bonym007]

As someone new to IoT, I'm currently tackling a project with ESP32 and Firebase. I'm encountering some difficulties in fetching a JSON object from a collection in the Realtime Database and incorporating it into my project. Could you kindly confirm if this is achievable? If so, I would greatly appreciate any assistance you could provide in this matter. Thank you very much.

[mobizt]

This library provides the complete feature examples that provided by Firebase Realtime database REST APIs.

You have to describe in detail for what you've done, what is the error and what is your expectation with the example code.

[bonym007]

I was able to connect to the Realtime database from my ESP32 and fetch the data individually, but may be because of multiple request to firebase, the code execution seems to be slow. So I thought of getting value as a json object from a collection in firebase instead of getting the data from individual node. Below I am attaching the code. Inside the loop now I am getting the value for individual node, what I am checking is to get the value as JSON so that I can reduce the requests.

`#include <Firebase_ESP_Client.h>
#include "addons/TokenHelper.h"
#include "addons/RTDBHelper.h"
#include "time.h"

#define API_KEY "xxxxxxxxxxxxxxxxxxxxx"
#define DATABASE_URL "xxxxxxxxxxxxxxxxxx"

FirebaseData fbdo;
FirebaseAuth auth;
FirebaseConfig config;
FirebaseJson json;

String esp32_pin_config_path = "Esp32Config";

String buzer_config_path = "Buzer";
String dht11_config_path = "DHT-11 Sensor";
String flame_config_path = "Flame Sensor";
String led_config_path = "LED";
String mq135_config_path = "MQ-135 Sensor";
String mq2_config_path = "MQ-2 Sensor";
String water_config_path = "Water Level Sensor";

bool buzer_config_value;
bool dht11_config_value;
bool flame_config_value;
bool led_config_value;
bool mq135_config_value;
bool mq2_config_value;
bool water_config_value;

String threshold_values_path = "ThresholdValues";
String acetone_threshold_path= "Acetone";
String co2_threshold_path= "CO2";
String flame_threshold_path= "Flame";
String lpg_threshold_path = "LPG";
String temperature_threshold_path = "Temperature";
String water_level_threshold_path= "Water";

bool getValueFromFirebase(String path) {
// FirebaseData data;
if (Firebase.RTDB.getBool(&fbdo, path)) {
if (fbdo.dataType() == "boolean") {
return fbdo.boolData();
}
else {
Serial.println("Error: Data type is not boolean");
return false;
}
} else {
Serial.println("Error: Failed to get value from Firebase");
return false;
}
}

float getFloatValue(String path)
{
if (Firebase.RTDB.getFloat(&fbdo, path))
{
return fbdo.floatData();
}
else{
return 0;
}

void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
// dht.begin();
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to WiFi...");
}
configTime(0, 0, ntpServer);
config.api_key = API_KEY;
config.database_url = DATABASE_URL;

if(Firebase.signUp(&config,&auth,"",""))
{
Serial.println("Sign Up OK");
signupOK = true;
}
else{
Serial.println(config.signer.signupError.message.c_str());
}

config.token_status_callback = tokenStatusCallback;
Firebase.begin(&config, &auth);
Firebase.reconnectWiFi(true);

}

void loop() {
// put your main code here, to run repeatedly:
if(Firebase.ready() && signupOK && (millis()-sendDataPrevMillis > 1000 || sendDataPrevMillis ==0))
{

// getting config value from firebase
buzer_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + buzer_config_path);
dht11_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + dht11_config_path);
flame_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + flame_config_path);
led_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + led_config_path);
mq135_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + mq135_config_path);
mq2_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + mq2_config_path);
water_config_value = getValueFromFirebase(esp32_pin_config_path + "/" + water_config_path);

int water_level_threshold= getFloatValue(threshold_values_path+"/"+water_level_threshold_path);
int acetone_threshold = getFloatValue(threshold_values_path+"/"+acetone_threshold_path);
int co2_threshold= getFloatValue(threshold_values_path+"/"+co2_threshold_path);
int flame_threshold= getFloatValue(threshold_values_path+"/"+flame_threshold_path);
int lpg_threshold= getFloatValue(threshold_values_path+"/"+lpg_threshold_path);
int temperature_threshold= getFloatValue(threshold_values_path+"/"+temperature_threshold_path);

}

}
`
The values may change in the db and I need to get the latest values, that is why I put them inside the loop(), hope you understand my issue. Thank you

[mobizt]

You are posting on the wrong place.

This is the FirebaseClient library repo not Firebase-ESP-Client library repo.

Any way your code shows that you have the problem with the lack of basic understanding of Firebase Realtime database concepts and what the service provided.

You cannot use it in the same way as MQTT and Web socket technology.

It is the REST Client which involved the HTTP request and response. The header with extras 1k bearer token or access key was sent every request which causes the large data usage bandwidth when you do as in your code that is completely sending a bulk http request continuously in the infinite loop which is not make any sense and I don't get why you do that.

You should redesign your code and concept with less data and speed in mind if you still want to use Firebase Realtime database otherwise MQTT and web socket with your own server may be suitable for your needs.

[mobizt]

It should be event-driven application in embedded application instead of polling read plenty of data every 1 second.

In the Firebase Realtime database, you should learn why Google uses the word "Realtime" in its product.

And learn how to use it in "Realtime" as it was claimed in its features.

[bonym007]

It was great to learn new information. Thank you for helping me out.