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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.HostFiltering;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Hosting.StaticWebAssets;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.AspNetCore.Server.Kestrel.Core;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
namespace Microsoft.AspNetCore;
/// <summary>
/// Provides convenience methods for creating instances of <see cref="IWebHost"/> and <see cref="IWebHostBuilder"/> with pre-configured defaults.
/// </summary>
public static class WebHost
{
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="app">A delegate that handles requests to the application.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost Start(RequestDelegate app) =>
Start(url: null!, app: app);
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="url">The URL the hosted application will listen on.</param>
/// <param name="app">A delegate that handles requests to the application.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost Start([StringSyntax(StringSyntaxAttribute.Uri)] string url, RequestDelegate app)
{
var startupAssemblyName = app.GetMethodInfo().DeclaringType!.Assembly.GetName().Name;
return StartWith(url: url, configureServices: null, app: appBuilder => appBuilder.Run(app), applicationName: startupAssemblyName);
}
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="routeBuilder">A delegate that configures the router for handling requests to the application.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost Start(Action<IRouteBuilder> routeBuilder) =>
Start(url: null!, routeBuilder: routeBuilder);
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="url">The URL the hosted application will listen on.</param>
/// <param name="routeBuilder">A delegate that configures the router for handling requests to the application.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost Start([StringSyntax(StringSyntaxAttribute.Uri)] string url, Action<IRouteBuilder> routeBuilder)
{
var startupAssemblyName = routeBuilder.GetMethodInfo().DeclaringType!.Assembly.GetName().Name;
return StartWith(url, services => services.AddRouting(), appBuilder => appBuilder.UseRouter(routeBuilder), applicationName: startupAssemblyName);
}
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="app">The delegate that configures the <see cref="IApplicationBuilder"/>.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost StartWith(Action<IApplicationBuilder> app) =>
StartWith(url: null!, app: app);
/// <summary>
/// Initializes and starts a new <see cref="IWebHost"/> with pre-configured defaults.
/// See <see cref="CreateDefaultBuilder()"/> for details.
/// </summary>
/// <param name="url">The URL the hosted application will listen on.</param>
/// <param name="app">The delegate that configures the <see cref="IApplicationBuilder"/>.</param>
/// <returns>A started <see cref="IWebHost"/> that hosts the application.</returns>
public static IWebHost StartWith([StringSyntax(StringSyntaxAttribute.Uri)] string url, Action<IApplicationBuilder> app) =>
StartWith(url: url, configureServices: null, app: app, applicationName: null);
private static IWebHost StartWith(string? url, Action<IServiceCollection>? configureServices, Action<IApplicationBuilder> app, string? applicationName)
{
var builder = CreateDefaultBuilder();
if (!string.IsNullOrEmpty(url))
{
builder.UseUrls(url);
}
if (configureServices != null)
{
builder.ConfigureServices(configureServices);
}
builder.Configure(app);
if (!string.IsNullOrEmpty(applicationName))
{
builder.UseSetting(WebHostDefaults.ApplicationKey, applicationName);
}
var host = builder.Build();
host.Start();
return host;
}
/// <summary>
/// Initializes a new instance of the <see cref="WebHostBuilder"/> class with pre-configured defaults.
/// </summary>
/// <remarks>
/// The following defaults are applied to the returned <see cref="WebHostBuilder"/>:
/// use Kestrel as the web server and configure it using the application's configuration providers,
/// set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/>,
/// load <see cref="IConfiguration"/> from 'appsettings.json' and 'appsettings.[<see cref="IHostEnvironment.EnvironmentName"/>].json',
/// load <see cref="IConfiguration"/> from User Secrets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
/// load <see cref="IConfiguration"/> from environment variables,
/// configure the <see cref="ILoggerFactory"/> to log to the console and debug output,
/// adds the HostFiltering middleware,
/// adds the ForwardedHeaders middleware if ASPNETCORE_FORWARDEDHEADERS_ENABLED=true,
/// and enable IIS integration.
/// </remarks>
/// <returns>The initialized <see cref="IWebHostBuilder"/>.</returns>
public static IWebHostBuilder CreateDefaultBuilder() =>
CreateDefaultBuilder(args: null!);
/// <summary>
/// Initializes a new instance of the <see cref="WebHostBuilder"/> class with pre-configured defaults.
/// </summary>
/// <remarks>
/// The following defaults are applied to the returned <see cref="WebHostBuilder"/>:
/// use Kestrel as the web server and configure it using the application's configuration providers,
/// set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/>,
/// load <see cref="IConfiguration"/> from 'appsettings.json' and 'appsettings.[<see cref="IHostEnvironment.EnvironmentName"/>].json',
/// load <see cref="IConfiguration"/> from User Secrets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
/// load <see cref="IConfiguration"/> from environment variables,
/// load <see cref="IConfiguration"/> from supplied command line args,
/// configure the <see cref="ILoggerFactory"/> to log to the console and debug output,
/// configure the <see cref="IWebHostEnvironment.WebRootFileProvider"/> to map static web assets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
/// adds the HostFiltering middleware,
/// adds the ForwardedHeaders middleware if ASPNETCORE_FORWARDEDHEADERS_ENABLED=true,
/// and enable IIS integration.
/// </remarks>
/// <param name="args">The command line args.</param>
/// <returns>The initialized <see cref="IWebHostBuilder"/>.</returns>
public static IWebHostBuilder CreateDefaultBuilder(string[] args)
{
var builder = new WebHostBuilder();
if (string.IsNullOrEmpty(builder.GetSetting(WebHostDefaults.ContentRootKey)))
{
builder.UseContentRoot(Directory.GetCurrentDirectory());
}
if (args != null)
{
builder.UseConfiguration(new ConfigurationBuilder().AddCommandLine(args).Build());
}
builder.ConfigureAppConfiguration((hostingContext, config) =>
{
var env = hostingContext.HostingEnvironment;
config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true);
if (env.IsDevelopment())
{
if (!string.IsNullOrEmpty(env.ApplicationName))
{
var appAssembly = Assembly.Load(new AssemblyName(env.ApplicationName));
if (appAssembly != null)
{
config.AddUserSecrets(appAssembly, optional: true);
}
}
}
config.AddEnvironmentVariables();
if (args != null)
{
config.AddCommandLine(args);
}
})
.ConfigureLogging((hostingContext, loggingBuilder) =>
{
loggingBuilder.Configure(options =>
{
options.ActivityTrackingOptions = ActivityTrackingOptions.SpanId
| ActivityTrackingOptions.TraceId
| ActivityTrackingOptions.ParentId;
});
loggingBuilder.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
loggingBuilder.AddConsole();
loggingBuilder.AddDebug();
loggingBuilder.AddEventSourceLogger();
}).
UseDefaultServiceProvider((context, options) =>
{
options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
});
ConfigureWebDefaults(builder);
return builder;
}
internal static void ConfigureWebDefaults(IWebHostBuilder builder)
{
builder.ConfigureAppConfiguration((ctx, cb) =>
{
if (ctx.HostingEnvironment.IsDevelopment())
{
StaticWebAssetsLoader.UseStaticWebAssets(ctx.HostingEnvironment, ctx.Configuration);
}
});
ConfigureWebDefaultsWorker(
builder.UseKestrel(ConfigureKestrel),
services =>
{
services.AddRouting();
});
builder
.UseIIS()
.UseIISIntegration();
}
internal static void ConfigureWebDefaultsSlim(IWebHostBuilder builder)
{
ConfigureWebDefaultsWorker(builder.UseKestrelCore().ConfigureKestrel(ConfigureKestrel), configureRouting: null);
}
private static void ConfigureKestrel(WebHostBuilderContext builderContext, KestrelServerOptions options)
{
options.Configure(builderContext.Configuration.GetSection("Kestrel"), reloadOnChange: true);
}
private static void ConfigureWebDefaultsWorker(IWebHostBuilder builder, Action<IServiceCollection>? configureRouting)
{
builder.ConfigureServices((hostingContext, services) =>
{
// Fallback
services.PostConfigure<HostFilteringOptions>(options =>
{
if (options.AllowedHosts == null || options.AllowedHosts.Count == 0)
{
// "AllowedHosts": "localhost;127.0.0.1;[::1]"
var hosts = hostingContext.Configuration["AllowedHosts"]?.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
// Fall back to "*" to disable.
options.AllowedHosts = (hosts?.Length > 0 ? hosts : new[] { "*" });
}
});
// Change notification
services.AddSingleton<IOptionsChangeTokenSource<HostFilteringOptions>>(
new ConfigurationChangeTokenSource<HostFilteringOptions>(hostingContext.Configuration));
services.AddTransient<IStartupFilter, HostFilteringStartupFilter>();
services.AddTransient<IStartupFilter, ForwardedHeadersStartupFilter>();
services.AddTransient<IConfigureOptions<ForwardedHeadersOptions>, ForwardedHeadersOptionsSetup>();
// Provide a way for the default host builder to configure routing. This probably means calling AddRouting.
// A lambda is used here because we don't want to reference AddRouting directly because of trimming.
// This avoids the overhead of calling AddRoutingCore multiple times on app startup.
if (configureRouting == null)
{
services.AddRoutingCore();
}
else
{
configureRouting(services);
}
});
}
/// <summary>
/// Initializes a new instance of the <see cref="WebHostBuilder"/> class with pre-configured defaults using typed Startup.
/// </summary>
/// <remarks>
/// The following defaults are applied to the returned <see cref="WebHostBuilder"/>:
/// use Kestrel as the web server and configure it using the application's configuration providers,
/// set the <see cref="IHostEnvironment.ContentRootPath"/> to the result of <see cref="Directory.GetCurrentDirectory()"/>,
/// load <see cref="IConfiguration"/> from 'appsettings.json' and 'appsettings.[<see cref="IHostEnvironment.EnvironmentName"/>].json',
/// load <see cref="IConfiguration"/> from User Secrets when <see cref="IHostEnvironment.EnvironmentName"/> is 'Development' using the entry assembly,
/// load <see cref="IConfiguration"/> from environment variables,
/// load <see cref="IConfiguration"/> from supplied command line args,
/// configure the <see cref="ILoggerFactory"/> to log to the console and debug output,
/// enable IIS integration.
/// </remarks>
/// <typeparam name ="TStartup">The type containing the startup methods for the application.</typeparam>
/// <param name="args">The command line args.</param>
/// <returns>The initialized <see cref="IWebHostBuilder"/>.</returns>
public static IWebHostBuilder CreateDefaultBuilder<[DynamicallyAccessedMembers(StartupLinkerOptions.Accessibility)] TStartup>(string[] args) where TStartup : class =>
CreateDefaultBuilder(args).UseStartup<TStartup>();
}
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