In ASP.NET Core, the IHostingEnvironment interface (renamed to IWebHostEnvironment in later versions) is used to provide information about the hosting environment in which the application is running. It allows developers to access various properties and methods related to the environment, facilitating environment-specific behavior and configuration.

The main purposes of the IHostingEnvironment interface are:

Environment detection: The IHostingEnvironment interface provides properties that allow you to determine the current hosting environment. Common properties include EnvironmentName (e.g., “Development,” “Staging,” “Production”) and IsDevelopment, IsStaging, and IsProduction boolean flags. These properties help you identify the current environment and adjust the application’s behavior accordingly.

Configuration file selection: The IHostingEnvironment interface plays a role in loading environment-specific configuration files. It is used to determine which configuration file, such as appsettings.{Environment}.json, should be loaded based on the current environment. This enables you to have different configuration settings for each environment.

File path resolution: The IHostingEnvironment interface provides methods to resolve file paths within the hosting environment. For example, you can use the ContentRootPath property to get the root path of the application, and the WebRootPath property to get the root path of the web content (e.g., static files). These methods help in locating and accessing files and resources within the application.

Application lifetime and shutdown: The IHostingEnvironment interface is also used during application startup and shutdown. It provides access to events like ApplicationStarted and ApplicationStopping, allowing you to perform specific tasks or execute code when the application starts or stops.

Overall, the IHostingEnvironment interface is an essential component in ASP.NET Core, providing information and functionality related to the hosting environment. It enables developers to build applications that adapt to different environments, load environment-specific configurations, resolve file paths, and perform environment-specific actions during application startup and shutdown.

Provides information about the web hosting environment an application is running in.

In ASP.NET Core 3.0, IHostingEnvironment interfaces is marked obsolete. You can still use them, but you’ll get warnings at build time. Instead, two new interfaces have been introduced: IHostEnvironment and IWebHostEnvironment which are alternative to use.