How to get base url without accessing a request

You are right, hosting URL is an external information, and you can simply pass it as configuration parameter to your application.

Maybe this will help you somehow: without request, you can get a configured listening address (like http://+:5000) using the IWebHostBuilder interface. It provides access to host settings via the GetSetting method:

/// <summary>
/// Get the setting value from the configuration.
/// </summary>
/// <param name="key">The key of the setting to look up.</param>
/// <returns>The value the setting currently contains.</returns>
string GetSetting(string key);

There is a WebHostDefaults.ServerUrlsKey setting name, that allows to configure listening address. We override it when add .UseUrls extension method:

public static IWebHostBuilder UseUrls(this IWebHostBuilder hostBuilder, params string[] urls);

or define urls configuration parameter as described in the documentation (you know, by default listening is configured to localhost:5000).

So, having instance of IWebHostBuilder, you can call .GetSetting(WebHostDefaults.ServerUrlsKey) and get the current value.

i needed for some reason to get the base URL in Start.cs Configure, so i come up with this

var URLS = app.ServerFeatures.Get<IServerAddressesFeature>().Addresses;