Rtl.Configuration.Validation

Rtl.Configuration.Validation is a package with an extention method for IServiceCollection that adds config class and binds it to a section from IConfiguration:

public void ConfigureServices(IServiceCollection services)
{
    // Instead of this line:
    // services.Configure<MyConfiguration>(Configuration.GetSection("MyConfig"));
    // use this one:
    services.AddConfig<MyConfiguration>(Configuration, "MyConfig");
}

The benefit over normal services.Configure is that you can annotate config class with attributes from System.ComponentModel.DataAnnotations:

public class MyConfiguration
{
    [Required]
    public string Name { get; set; }

    [Range(0, 10)]
    public int Value { get; set; }
}

Now if your configuration doesn't meet requirements set by these attributes the code will throw. It will throw after ConfigureServices method but before Configure method so you can be sure that everything is all right before pipeline starts.

Complex objects and collections are also supported

Example

public class Config
{
    [Required]
    public string Id { get; set; }
    public Person Person { get; set; }
    public IEnumerable<Person> People { get; set; }
}

public class Person
{
    [Required]
    public string Name { get; set; }
    [Range(1, 100)]
    public int Age { get; set; }
}

Given this definition of Config class the code services.AddConfig<Config>(Configuration, "MyConfig"); will throw if:

• Config.Id is empty
• Person.Name is not set or empty in Config.Person object or in any item from Config.People collection
• Person.age is default (zero) or any other outside range from 1 to 100

Note that Config.Person and Config.People properties can be null because they are not required

Api

AddConfig

public static IServiceCollection AddConfig<T>(this IServiceCollection services, IConfiguration configuration, string sectionName)
    where T : class, new()

Adds IOptions<T> to IoC container, validates config before Startup.Configure is called

GetConfig

public static T GetConfig<T>(this IConfiguration configuration, string sectionName)
    where T : class, new()

Gets config of type T from configuration, validates and returns it. Use this method when you don't need to add IOptions and you want to get validated config inside ConfigureServices method and use right away