I am encountering an issue while working on a Flutter project. I am trying to make an HTTP request to a server with the following code:

Future<String> getTargetVersion() async {
    String kioskId = ConfigLoader().getKioskId;
    String apiKey = 'myAPIKEY';
    String versionCheckUrl = 'https://ai.wizservice.co.kr:1002/api/kiosk/$kioskId/config';
    var url = Uri.parse(versionCheckUrl);
    try {
        var response = await http.get(url,
            headers: <String, String>{
                'X-Authorization': apiKey,
            },
        );
        if (response.statusCode == 200) {
            var jsonResponse = json.decode(response.body);
            var version = jsonResponse['version'];
            return version;
        } else {
            logger.e("Failed to load version");
            throw Exception('Failed to load version');
        }
    } catch(e){
        writeAppLog("An error occurred while fetching the target version: $e");
        throw Exception('Failed to load version');
    }
}

However, I am encountering the following error:
“handshakeexception: handshake error in client (os error: i/flutter (27098): │ ! certificate_verify_failed: certificate has expired(handshake.cc:393)).”
I suspect this is due to an expired SSL certificate on the server.

Could anyone suggest how I can handle this issue? I have considered bypassing SSL certificate validation using the badCertificateCallback, but I am encountering difficulties implementing it due to null safety issues. Are there any other approaches or best practices to handle this situation effectively?

class MyHttpOverrides extends HttpOverrides {
  @override
  HttpClient createHttpClient(SecurityContext? context) {
    return super.createHttpClient(context)
      ..badCertificateCallback =      
          (X509Certificate cert, String host, int port) => true;
  }
}

A value of type ‘bool Function(X509Certificate, String, int)’ can’t be assigned to a variable of type ‘bool Function(X509Certificate, String, int)?’. (Documentation) Try changing the type of the variable, or casting the right-hand type to ‘bool Function(X509Certificate, String, int)?’.

I encountered an error like this.

I’m sorry for posting this using a translator because my English is not good. There are many answers, but I tried to solve the problem with those answers but failed, so I’m posting the question like this.

Thank you in advance for any insights or suggestions.