Different services need using different configuration parameters to run. This library makes it easy to create a configuration object with any set of parameters from Map of parameter's values. The Map can be obtained in any suitable way, for example, from yaml-file or by http.
You will never forget to set default values for all parameters. You can easyly set rules checking for any parameter value Any parameter can be also a configuration object.
To get parameter value for your service is as easy as config.parameter
A simple usage example:
import 'package:config/config.dart';
/// Description of service configuration parameters
class MyServiceConfig extends Config {
/// Default values (required)
static final Map<String, dynamic> _defaults = {
'stringParam': 'default string',
'intParam': 0,
'subconfig': new MyServiceSubconfig()
};
/// Rules to check config parameters (not required)
static final Map<String, ConfigRule> _rules = {
'stringParam': ConfigRule.isString,
'intParam': new intParamRule(),
'subconfig': ConfigRule.isMap
};
/// Config bulders (not required)
///
/// If a parameter is a child-config then you must declare how to create it
static final Map<String, ConfigBuilder> _builders = {
'subconfig': (Map<String, dynamic> configData) => new MyServiceSubconfig(configData)
};
/// Creates new service configuration
MyServiceConfig([Map<String, dynamic> configData])
: super(configData ?? {}, defaults: _defaults, rules: _rules, builders: _builders);
/// `stringParam` getter
String get stringParam => get('stringParam') as String;
/// `intParam` getter
int get intParam => get('intParam') as int;
/// `subconfig` getter
MyServiceSubconfig get subconfig => get('subconfig') as MyServiceSubconfig;
}
/// Custom rule for `intParam`
///
/// `check` function returns normally if everythin is OK or throws an [Exception]
class intParamRule implements ConfigRule {
@override
check(String name, dynamic value) {
ConfigRule.isInt.check(name, value);
if (value < 0 || value > 10) {
throw new ConfigValueException(name, value, 'greater then 0 and less then 10');
}
}
}
/// Service child-config
class MyServiceSubconfig extends Config {
static final Map<String, dynamic> _defaults = {
'param': 'default subconfig param value'
};
static final Map<String, dynamic> _rules = {
'param': ConfigRule.isString
};
MyServiceSubconfig([Map<String,dynamic> configData])
: super(configData ?? {}, defaults: _defaults, rules: _rules);
String get param => get('param') as String;
}Full usage example see in the example directory