Feature request : multiple Wi-Fi networks backups

[Dayzen]

Hello dchristl,

I found your email but I think maybe you prefer that I reach here.

I would like to request a feature that enables the ESP32 to connect to multiple Wi-Fi networks as backups, ensuring a reliable connection for the Access Point.

I'm all new to esp32 dev, but I tried to make most of the implementation, I hope it'll help making this features out soon

#include <WiFi.h>
#include <HTTPClient.h>

// List of networks with SSID and password, ordered by priority
const String networks[] = {
    "SSID1:Password1",
    "SSID2:Password2",
    // Add more networks here as needed
};

// Time (in milliseconds) to wait before retrying to connect to the highest priority network
const unsigned long reconnectDelay = 5 * 60 * 1000; // 5 minutes

// Maximum number of connection attempts
const int maxAttempts = 3;

// Last time the ESP32 attempted to reconnect
unsigned long lastReconnectAttempt = 0;

// Function to connect to a specified network
bool connectNetwork(const String& ssid, const String& password) {
    WiFi.begin(ssid.c_str(), password.c_str());

    // Wait for connection
    int attempts = 0;
    while (WiFi.status() != WL_CONNECTED && attempts < maxAttempts) {
        delay(1000); // Wait 1 second before retrying
        attempts++;
    }

    // Check if connected
    return (WiFi.status() == WL_CONNECTED);
}

// Function to check internet connectivity by pinging Google
bool checkInternetConnection() {
    HTTPClient http;
    http.begin("http://www.google.com");
    int httpCode = http.GET();
    http.end();
    
    // Return true if HTTP code is 200 (OK)
    return (httpCode == 200);
}

// Attempt to connect to the highest priority network with internet access
void connectToFirstNetworkUP() {
    for (int i = 0; i < sizeof(networks) / sizeof(networks[0]); i++) {
        String ssid = networks[i].substring(0, networks[i].indexOf(':'));
        String password = networks[i].substring(networks[i].indexOf(':') + 1);
        
        if (ssid.length() > 0 && password.length() > 0) {
            if (connectNetwork(ssid, password)) {
                Serial.println("Connected to " + ssid);
                
                // Check internet connection
                if (checkInternetConnection()) {
                    Serial.println("Internet connection is available.");
                    return; // Successfully connected to a network with internet
                } else {
                    Serial.println("No internet connection.");
                }
            } else {
                Serial.println("Failed to connect to " + ssid);
            }
        }
    }
    Serial.println("No available networks with internet.");
}

void setup() {
    Serial.begin(115200);
    connectToFirstNetworkUP();
}

void loop() {
    unsigned long currentMillis = millis();

    if (checkInternetConnection()) {
        // Currently connected and has internet 
        if (WiFi.SSID() != networks[0].substring(0, networks[0].indexOf(':'))) {
            // If not connected to the highest priority network
            if (currentMillis - lastReconnectAttempt >= reconnectDelay) {
              // If a certain amount of time passed since we lost the highest priority network
                Serial.println("Switching to highest priority network...");
                connectToFirstNetworkUP();
                lastReconnectAttempt = currentMillis; // Update the last attempt time
            }
        }
    } else {
        // Not connected or no internet, attempt to reconnect asap
          Serial.println("Reconnecting to highest priority network...");
          connectToFirstNetworkUP();
          lastReconnectAttempt = currentMillis; // Update the last attempt time
    }
    
    delay(5000); // Wait for 5 seconds before next loop iteration
}

I believe this enhancement will greatly improve the reliability of the network connection provided by the ESP32.

Thank you for considering this request.

[dchristl]

Hello @Dayzen,

I'm keeping this feature in mind, but don't have time to implement it at the moment. There are also a lot of other features that I would like to implement first.

Kind Regards,
Danny