ASP.NET Core Configuration

Overview

ASP.NET Core provides several ways to configure your application. This includes:

• Configuration Files: Appsettings.json
• Environment Variables: Setting configuration values based on the environment
• Command-line Arguments: Passing configuration values when starting the application
• Dependency Injection Container: Registering configuration settings using dependency injection

Appsettings.json

The Appsettings.json file is the primary configuration source for ASP.NET Core applications. It allows you to define various configuration settings in a structured format.

{
    "Logging": {
        "LogLevel": {
            "Default": "Information",
            "Microsoft.AspNetCore.Mvc": "Warning"
        }
    },
    "AllowedHosts": "*",
    "Database": {
        "ConnectionString": "Data Source=localhost;Initial Catalog=MyDatabase;Integrated Security=True;"
    }
}

You can define different configurations for different environments (Development, Production, etc.) by creating separate appsettings.{Environment}.json files. For example, appsettings.Development.json would contain development-specific settings.

Environment Variables

Environment variables allow you to configure your application without modifying the code. This is especially useful for deploying to different environments (e.g., development, staging, production).

    var connectionString = Environment.GetEnvironmentVariable("MyConnectionString");

You can set environment variables in your IDE, deployment platform, or operating system. Common environment variables include those for database connections, API keys, and other sensitive information.

Command-Line Arguments

You can pass configuration values to your application when starting it from the command line. This is useful for overriding default settings or providing configuration values during development.

    var port = int.Parse(args[0]);
    // Start the application listening on port port.

The args array contains the command-line arguments passed to the application.

Dependency Injection

You can also register configuration settings using the Dependency Injection container. This allows you to manage configuration settings as a dependency, making your code more testable and maintainable.

    services.Configure(options =>
    {
        options.Setting1 = "Value1";
        options.Setting2 = 123;
    });