How to configure Flutter Flavor for different API links - flutter

Question

I have 3 different API links for Staging, Development and Production Stages. I tried to configure the files in this way to share links
//Types of flavors we have
import 'dart:io';
//Types of flavors
enum Flavor {
STAGING,
DEVELOPMENT,
PRODUCTION,
}
class Config {
//Floavor is the way to devide application
//configurations depending on stage we work
static Flavor? appFlavor;
// api url for requests depending on the flavor
// you can use it by typing Config.api_url
static String get api_url {
switch (appFlavor) {
case Flavor.PRODUCTION:
return 'https://api.Link1';
case Flavor.DEVELOPMENT:
return 'https://api.Link2';
case Flavor.STAGING:
return 'https://api.Link3';
default:
return 'https://api.Link2';
}
}
//getting information about platform
//you can use it by typing Config.platform
static String get platform => Platform.isAndroid ? 'ANDROID' : 'IOS';
}
Then I initialise the flavor in main.dart in the following way :
void main() {
//Initialising the flavor
Config.appFlavor = Flavor.PRODUCTION;
Bloc.observer = AppBlocObserver();
FlutterError.onError = (details) {
log(details.exceptionAsString(), stackTrace: details.stack);
};
runZonedGuarded(
() => runApp(const IChazy()),
(error, stackTrace) => log(error.toString(), stackTrace: stackTrace),
);
}
But then when I try to pass the data to Chopper package for baseURL it shows me mistake that I should use the const value:
import 'package:chopper/chopper.dart';
import 'package:ichazy/config/flavor_config.dart';
//part 'challenges_api_service.chopper.dart';
#ChopperApi(baseUrl: Config.api_url) //Error Appears here
abstract class ChallengeApiService {}
The Error:
Const variables must be initialized with a constant value.
Try changing the initializer to be a constant expression.
I know that I should use const value in order to cancel this error but in the same time I want to switch flavors and API links. Is there any proper way to somehow manage this two goals, maybe by changing Config class?
Thank you in advance.

Answer 1

The only way I found is to use custom create method in the chopper package
#ChopperApi(baseUrl: '/')
abstract class ChallengeApiService extends ChopperService {
#Get()
Future<Response> getChallenges(
#Body() Map<String, dynamic> body,
);
static ChallengeApiService create() {
final client = ChopperClient(
baseUrl: Config.api_url,
services: [_$ChallengeApiService()],
converter: JsonConverter());
return _$ChallengeApiService(client);
}
}