appsettings.json in .NET Core Console Apps

When creating a .NET Core console application, it's handy to have Web API style appsettings.json to configure the application.

{
  "AppConfig": {
    "DatabaseConnectionString":
      "Data source=(LocalDb)\\MSSQLLocalDB;Initial Catalog=Dev;Integrated Security=True"
  }
}

It would be nice to bind this to a concrete class.

    class AppConfig
    {
        public string DatabaseConnectionString { get; set; }
    }

1. Install NuGet packages

   • Microsoft.Extensions.Configuration
   • Microsoft.Extensions.Configuration.Binder
   • Microsoft.Extensions.Configuration.Json

2. Add an extension method to IConfiguration

   public static class ConfigurationExtensions
       {
           public static T ParseAs<T>(this IConfiguration configuration, string path)
               where T : new()
           {
               var result = new T();
               configuration.GetSection(path).Bind(result);
               return result;
           }
       }
   

3. Use the configuration in your program

       class Program
       {
           static void Main(string[] args)
           {
               var configuration = GetStandardConfigurationBuilder();
               var appConfig = configuration.ParseAs<AppConfig>("AppConfig");
               Console.WriteLine(appConfig.DatabaseConnectionString);
           }
   
           internal static IConfiguration GetStandardConfigurationBuilder()
           {
               return new ConfigurationBuilder()
                   .AddJsonFile("appsettings.json").Build();
           }
       }