《ASP.NET Core 高性能系列》ASP.NET Core的启动过程(1)

public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
}

            public
            interface
             IHostBuilder
{
    IDictionary<object, object> Properties
    {
        get;
    }
　　//宿主程序的配置
    IHostBuilder ConfigureHostConfiguration(Action<IConfigurationBuilder> configureDelegate);
　　//应用程序的配置
    IHostBuilder ConfigureAppConfiguration(Action<HostBuilderContext, IConfigurationBuilder> configureDelegate);
　　//添加service到容器
    IHostBuilder ConfigureServices(Action<HostBuilderContext, IServiceCollection> configureDelegate);
    IHostBuilder UseServiceProviderFactory<TContainerBuilder>(IServiceProviderFactory<TContainerBuilder> factory);
　　//覆盖用于创建ServiceProvider的工厂。
    IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Func<HostBuilderContext, IServiceProviderFactory<TContainerBuilder>> factory);
/　　/配置依赖注入的容器
    IHostBuilder ConfigureContainer<TContainerBuilder>(Action<HostBuilderContext, TContainerBuilder> configureDelegate);

    IHost Build();
}

public static IHostBuilder CreateDefaultBuilder(string[] args)
{
	HostBuilder hostBuilder = new HostBuilder();
	hostBuilder.UseContentRoot(Directory.GetCurrentDirectory());
//设置Host的配置信息
	hostBuilder.ConfigureHostConfiguration((Action<IConfigurationBuilder>)delegate(IConfigurationBuilder config)
	{
		config.AddEnvironmentVariables("DOTNET_");
		if (args != null)
		{
			config.AddCommandLine(args);
		}
	});
//设置应用程序的配置信息
	hostBuilder.ConfigureAppConfiguration((Action<HostBuilderContext, IConfigurationBuilder>)delegate(HostBuilderContext hostingContext, IConfigurationBuilder config)
	{
		IHostEnvironment hostingEnvironment = hostingContext.HostingEnvironment;
		config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true).AddJsonFile("appsettings." + hostingEnvironment.EnvironmentName + ".json", optional: true, reloadOnChange: true);
		if (hostingEnvironment.IsDevelopment() && !string.IsNullOrEmpty(hostingEnvironment.ApplicationName))
		{
			Assembly assembly = Assembly.Load(new AssemblyName(hostingEnvironment.ApplicationName));
			if (assembly != null)
			{
				config.AddUserSecrets(assembly, optional: true);
			}
		}
		config.AddEnvironmentVariables();
		if (args != null)
		{
			config.AddCommandLine(args);
		}
	})//设置日志的相关配置
       .ConfigureLogging((Action<HostBuilderContext, ILoggingBuilder>)delegate(HostBuilderContext hostingContext, ILoggingBuilder logging)
	{
		bool num = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
		if (num)
		{
			logging.AddFilter<EventLogLoggerProvider>((LogLevel level) => level >= LogLevel.Warning);
		}
		logging.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
		logging.AddConsole();
		logging.AddDebug();
		logging.AddEventSourceLogger();
		if (num)
		{
			logging.AddEventLog();
		}
	}).UseDefaultServiceProvider((Action<HostBuilderContext, ServiceProviderOptions>)delegate(HostBuilderContext context, ServiceProviderOptions options)
	{
		bool validateOnBuild = options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
		options.ValidateOnBuild = validateOnBuild;
	});
	return hostBuilder;
}

ContentRoot:  C:\MyApp\wwwroot
WebRoot:      C:\MyApp\wwwroot\wwwroot

    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public IConfiguration Configuration { get; }
        // 该方法会被运行时自动调用,通过此方法可将service添加到容器中.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews();
        }
        // 该方法会被运行时自动调用. 使用此方法配置 HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }
            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseRouting();
            app.UseAuthorization();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }