Dart has a standard way to externalize settings like Java properties? - dart

Question

I'm looking for the right way to externalize the settings in my server Dart application.
In Java the common way would be a property file. Exists something similar in Dart?

Answer 1

You can just use a Dart script for your settings. No point in using a different format if there is no specific reason.
With a simple import you have it available in a typed way.

Answer 2

When the Resource class is implemented, I would just use a JSON file that is deployed with my program.

Answer 3

You could use a global variables, for example:
DB_URL = 'localhost:5432/mydb';
DB_PASS = 'my_pass';
then you could create a different configuration file for every enviroment. For example, for production you could create a production_config.dart which could contains:
loadConfig() {
DB_URL = '123.123.123.123:5432/mydb';
DB_PASS = 'my_prod_pass';
}
Then in your main function you could call production_config.loadConfig if environment is production, for example:
import 'production_config.dart' as prodConfig;
main(List<String> args) {
var ENV = getEnvFromArgs(args);
if(ENV == 'PROD') {
prodConfig.loadConfig();
}
//do other stuff here
}
In that way if you want to change from development to production you only need to pass an argument to your dart program for example:
dart myprogram.dart -env=PROD
The advantages of this approach are that you don't need to create a separate properties, json or yaml file for this, and you don't need to parse them. Furthermore the properties are type-ckecked.

Answer 4

I like putting configuration in a Dart class like what Günter Zöchbauer was talking about, but there is also the option of using the safe_config package. With this you enter the values in a yaml file. Quoting from the docs:
You define a subclass of Configuration with those properties:
class ApplicationConfiguration extends Configuration {
ApplicationConfiguration(String fileName) :
super.fromFile(File(fileName));
int port;
String serverHeader;
}
Your YAML file should contain those two, case-sensitive keys:
port: 8000
serverHeader: booyah/1
To read your configuration file:
var config = new ApplicationConfiguration("config.yaml");
print("${config.port}"); // -> 8000
print("${config.serverHeader}"); // -> "booyah/1"
See also an example from a setup in Aqueduct.

Answer 5

main() {
var env = const String.fromEnvironment("ENV", defaultValue: "local");
print("Env === " + env);
}
Give environment as option while running Dart App
pub serve --port=9002 --define ENV=dev
References:
http://blog.sethladd.com/2013/12/compile-time-dead-code-elimination-with.html
https://github.com/dart-lang/sdk/issues/27998