SimpleConf

Configuration made simple!

How many times do you have to write a line of code like this?

var portString = 
	Environment.GetEnvironmentVariable("port");
	
portString = string.IsNullOrEmpty(portString) 
	? ConfigurationManager.AppSettings["port"] 
	: portString;

int port;
if (!Int32.TryParse(portString, out port)) {
	throw new Exception("No port, no bananas!");
}

(Well, maybe not many times but hey, I hope you got the point!)

What if I can use something as simple as this:

public interface ISampleConfiguration {
    int Port { get; }
}

// yada yada yada

var configuration = 
    new ConfigurationBuilder<ISampleConfiguration>()
	    .FromAppSettings()
	    .FromEnvironment()
	    .Build();

Now you can set the value in your AppSettings section in your configuration file or setting the value in your environment variables.

Prefixed values

Given a simple configuration setting like this:

<configuration>
	<appSettings>
		<add key="logging:key" value="abcd12345" />
		<add key="server-url" value="http://example.org" />
		<add key="server" value="http://boo.org" />
	</appSettings>
</configuration>

We can partition configuration in three different configuration interfaces:

public interface ILoggingConfiguration {
	string Key { get; }
}

public interface IServerConfiguration {
	string Url { get; }
}

public interface IConfiguration {
	string Url { get; }
}

We can grab the configuration in two ways:

• Using the configuration builder

var logCfg = new ConfigurationBuilder<ILoggingConfiguration>().WithPrefix("logging").Build();
	
var srvCfg = new ConfigurationBuilder<IServerConfiguration>().WithPrefix("server", "-").Build();

var cfg = new ConfigurationBuilder<IConfiguration>().Build();

• Using attributes

[KeyPrefix("logging:")]
public interface ILoggingConfiguration {
	string Key { get; }
}

[KeyPrefix("server-")]
public interface IServerConfiguration {
	string Url { get; }
}

public interface IConfiguration {
	string Url { get; }
}

Default values

We can provide default values using the DefaultValue Attribute. Right now, if a value is not present in any of the sources it will throw an exception in the moment the configuration class is build, except if you have a default value attribute applied to the property.

Type conversion

TypeConverters are supported, well, in fact, anything supported by Castle.DynamicDictionary is supported too. Just decorate the property with a TypeConverter attribute providing your custom TypeConverter and that's all, happiness is guaranteed.

Heavily inspired in this blog post from Krzysztof Koźmic. Thanks mate, you are awesome.