private RequestDelegate BuildApplication()
{
Debug.Assert(_applicationServices != null, "Initialize must be called first.");
try
{
_applicationServicesException?.Throw();
EnsureServer();
var builderFactory = _applicationServices.GetRequiredService <IApplicationBuilderFactory>();
var builder = builderFactory.CreateBuilder(Server.Features);
builder.ApplicationServices = _applicationServices;
var startupFilters = _applicationServices.GetService <IEnumerable <IStartupFilter> >();
Action <IApplicationBuilder> configure = _startup !.Configure;
if (startupFilters != null)
{
foreach (var filter in startupFilters.Reverse())
{
configure = filter.Configure(configure);
}
}
configure(builder);
return(builder.Build());
}
catch (Exception ex)
{
if (!_options.SuppressStatusMessages)
{
// Write errors to standard out so they can be retrieved when not in development mode.
Console.WriteLine("Application startup exception: " + ex.ToString());
}
var logger = _applicationServices.GetRequiredService <ILogger <WebHost> >();
logger.ApplicationError(ex);
if (!_options.CaptureStartupErrors)
{
throw;
}
EnsureServer();
// Generate an HTML error page.
var hostingEnv = _applicationServices.GetRequiredService <IHostEnvironment>();
var showDetailedErrors = hostingEnv.IsDevelopment() || _options.DetailedErrors;
return(ErrorPageBuilder.BuildErrorPageApplication(hostingEnv.ContentRootFileProvider, logger, showDetailedErrors, ex));
}
}
public async Task StartAsync(CancellationToken cancellationToken)
{
HostingEventSource.Log.HostStart();
var serverAddressesFeature = Server.Features.Get <IServerAddressesFeature>();
var addresses = serverAddressesFeature?.Addresses;
if (addresses != null && !addresses.IsReadOnly && addresses.Count == 0)
{
var urls = Configuration[WebHostDefaults.ServerUrlsKey];
if (!string.IsNullOrEmpty(urls))
{
serverAddressesFeature !.PreferHostingUrls = WebHostUtilities.ParseBool(Configuration, WebHostDefaults.PreferHostingUrlsKey);
foreach (var value in urls.Split(';', StringSplitOptions.RemoveEmptyEntries))
{
addresses.Add(value);
}
}
}
RequestDelegate?application = null;
try
{
var configure = Options.ConfigureApplication;
if (configure == null)
{
throw new InvalidOperationException($"No application configured. Please specify an application via IWebHostBuilder.UseStartup, IWebHostBuilder.Configure, or specifying the startup assembly via {nameof(WebHostDefaults.StartupAssemblyKey)} in the web host configuration.");
}
var builder = ApplicationBuilderFactory.CreateBuilder(Server.Features);
foreach (var filter in StartupFilters.Reverse())
{
configure = filter.Configure(configure);
}
configure(builder);
// Build the request pipeline
application = builder.Build();
}
catch (Exception ex)
{
Logger.ApplicationError(ex);
if (!Options.WebHostOptions.CaptureStartupErrors)
{
throw;
}
var showDetailedErrors = HostingEnvironment.IsDevelopment() || Options.WebHostOptions.DetailedErrors;
application = ErrorPageBuilder.BuildErrorPageApplication(HostingEnvironment.ContentRootFileProvider, Logger, showDetailedErrors, ex);
}
var httpApplication = new HostingApplication(application, Logger, DiagnosticListener, HttpContextFactory);
await Server.StartAsync(httpApplication, cancellationToken);
if (addresses != null)
{
foreach (var address in addresses)
{
LifetimeLogger.LogInformation("Now listening on: {address}", address);
}
}
if (Logger.IsEnabled(LogLevel.Debug))
{
foreach (var assembly in Options.WebHostOptions.GetFinalHostingStartupAssemblies())
{
Logger.LogDebug("Loaded hosting startup assembly {assemblyName}", assembly);
}
}
if (Options.HostingStartupExceptions != null)
{
foreach (var exception in Options.HostingStartupExceptions.InnerExceptions)
{
Logger.HostingStartupAssemblyError(exception);
}
}
}