ASP.NET Core - Environment Variable

ASP.NET Core - Environment Variable

Introduction

Environment variables play a crucial role in configuring and customizing applications. In ASP.NET Core, environment variables can be used to control various aspects of an application's behavior, such as database connection strings, API keys, and logging settings. This documentation provides a brief overview of how to work with environment variables in ASP.NET Core, including accessing and setting them within an application.

Accessing Environment Variables

To access environment variables within an ASP.NET Core application, the IConfiguration interface can be utilized. This interface provides a unified configuration system that can retrieve values from various sources, including environment variables.

Code Example:

csharp
using Microsoft.Extensions.Configuration;
using System;

class Program
{
    static void Main(string[] args)
    {
        IConfiguration configuration = new ConfigurationBuilder()
            .AddEnvironmentVariables()
            .Build();

        string connectionString = configuration["DatabaseConnectionString"];
        Console.WriteLine($"Database Connection String: {connectionString}");
    }
}

Explanation:

The above code demonstrates how to access an environment variable named "DatabaseConnectionString" using the IConfiguration interface. The ConfigurationBuilder class is used to create a configuration object. By calling the AddEnvironmentVariables() method, the configuration builder includes environment variables as a configuration source.

The configuration["DatabaseConnectionString"] statement retrieves the value of the environment variable named "DatabaseConnectionString". This value can then be used within the application as required. In this example, the retrieved connection string is displayed on the console.

Setting Environment Variables

Environment variables can be set at different levels, including the operating system level, the command line, or within the application's configuration files.

Code Example:

bash
# Linux/Mac
export DatabaseConnectionString="your_connection_string"

# Windows
setx DatabaseConnectionString "your_connection_string"

Explanation:

The provided code examples demonstrate how to set an environment variable named "DatabaseConnectionString" on different platforms.

• On Linux and macOS, the export command is used in the terminal to set the value of an environment variable. Replace "your_connection_string" with the desired value for the variable.

• On Windows, the setx command is used in the command prompt to set the value of an environment variable. Replace "your_connection_string" with the desired value for the variable.

Once the environment variable is set, it can be accessed within the ASP.NET Core application using the IConfiguration interface, as shown in the previous example.

Conclusion

Environment variables are a flexible and powerful way to configure ASP.NET Core applications. They allow for easy customization and configuration of various aspects of the application's behavior. By leveraging the IConfiguration interface, developers can seamlessly access and utilize environment variables within their ASP.NET Core projects.