,The ASP.NET Core Module generates a dynamic port to assign to the backend process. CreateDefaultBuilder calls the UseIISIntegration method. UseIISIntegration configures Kestrel to listen on the dynamic port at the localhost IP address (127.0.0.1). If the dynamic port is 1234, Kestrel listens at 127.0.0.1:1234. This configuration replaces other URL configurations provided by.
For IIS Integration, it works if you get the address after the WebHostBuilder.Build() have run.
var builder = CreateWebHostBuilder(args);
var webHost = builder.Build();
var addresses = webHost.ServerFeatures.Get<IServerAddressesFeature>().Addresses;
var address = addresses.FirstOrDefault();
AppDomain.CurrentDomain.SetData("BaseUrl", address ?? "");
webHost.Run();
and got the local Kestrel address in the HostedService like this:
string baseUrl = AppDomain.CurrentDomain.GetData("BaseUrl").ToString();
But there's a catch - this address is useless, because you can not make a request directly on this address. The IIS Integration middleware checks that only the IIS handler can make a request on this address. It produces a similar error:
<category>Microsoft.AspNetCore.Server.IISIntegration.IISMiddleware</category>
<state>'MS-ASPNETCORE-TOKEN' does not match the expected pairing token 'ed5bc610-b7b9-4c1c-9941-954d0579edfc', request rejected.</state>
And in general case (no IIS Integration) this method of getting the address does not work if you use Kestrel configured to run with a custom port (not 5000), or a dynamic port 0. In this case the address needs to be obtained in a delayed manner, only after the application started.
For this case i tried this way: In Configure method in the StartUp class, i saved in ServerAddressFeature in the private member.
private IServerAddressesFeature _serverAddressesFeature;
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
_serverAddressesFeature = app.ServerFeatures.Get<IServerAddressesFeature>();
... not related code here ...
And in the ConfigureServices method i added a dependency
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton<IServerAddressesFeature>((sp) => _serverAddressesFeature);
... not related code here ...
Then in a hosted service i obtain this saved feature using dependency injection, and use it to get the address.
It works, only get the address in the StartAsync method, not in the service constructor!
public class WarmUpService : IHostedService
{
private readonly ILogger _logger;
private readonly IServerAddressesFeature _saf;
public WarmUpService(ILogger<WarmUpService> logger, IServerAddressesFeature serverAddressesFeature)
{
_logger = logger;
_saf = serverAddressesFeature;
}
public async Task StartAsync(CancellationToken cancellationToken)
{
try
{
// the URL can be Got here
string baseUrl = _saf?.Addresses?.FirstOrDefault();
// await _WarmUp(baseUrl);
}
catch(Exception ex)
{
_logger.LogCritical(ex, "WarmUp Failed");
}
}
public Task StopAsync(CancellationToken cancellationToken)
{
return Task.CompletedTask;
}
}