Start Me Up: Configuration and DI in ASP.NET Core

Adoption of ASP.NET Core continues to grow in development shops around the world. The .NET community offers a nice selection of templates for getting a new project moving quickly. On the other hand, more complex applications may require you to go deeper than what comes out of the box. The configuration and dependency injection systems in ASP.NET Core are flexible and powerful, and it is worth understanding the details of how a modern web application on the framework spins up on start.

This session provides a walkthrough of the Startup and Program classes, the host and app builders, configuration, DI, and middleware. Learn how to build your own middleware providers and pipeline. Create custom extension methods to register services with your application quickly and easily. Leverage the power of ASP.NET Core to work best for you and your organization.

Transcript

1. #startMeUp C O N F I G A N D D I I N A S P . N E T C O R E @ j e f f r e y s t r a u ss
3. global.asax web.config
7. ASP.NET Core
8. ASP.NET Core PROGRAM STARTUP
9. host
10. public class Program { public static Main(string[] args) { CreateWebHostBuilder(args).Build().Run(); } public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>(); } PROGRAM.CS
11. public class Program { public static Main(string[] args) { CreateWebHostBuilder(args).Build().Run(); } public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>(); } PROGRAM.CS
12. public class Program { public static Main(string[] args) { CreateWebHostBuilder(args).Build().Run(); } public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>(); } PROGRAM.CS
13. IWebHostBuilder
14. WebHost.CreateDefaultBuilder
15. public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args) .UseStartup<Startup>(); PROGRAM.CS
16. public static IWebHostBuilder CreateWebHostBuilder(string[] args) => new WebHostBuilder() .UseContentRoot(Directory.GetCurrentDirectory()) .UseKestrel() .UseIISIntegration() .UseEnvironment("Development") .UseStartup<Startup>(); PROGRAM.CS
17. public static IWebHostBuilder CreateWebHostBuilder(string[] args) => new WebHostBuilder() .UseContentRoot(Directory.GetCurrentDirectory()) .UseKestrel() .UseIISIntegration() .UseEnvironment("Development") .UseStartup<Startup>(); PROGRAM.CS
18. public static IWebHostBuilder CreateWebHostBuilder(string[] args) => new WebHostBuilder() .UseContentRoot(Directory.GetCurrentDirectory()) .UseKestrel() .UseIISIntegration() .UseEnvironment("Development") .UseStartup<Startup>(); PROGRAM.CS
19. 3.0
20. generic host
21. generic host MESSAGING BACKGROUND TASKS NON-HTTP
22. public class Program { public static Main(string[] args) { CreateHostBuilder(args).Build().Run(); } public static IHostBuilder CreateHostBuilder(string[] args) => Host.CreateDefaultBuilder(args); } PROGRAM.CS
23. public class Program { public static Main(string[] args) { CreateHostBuilder(args).Build().Run(); } public static IHostBuilder CreateHostBuilder(string[] args) => Host.CreateDefaultBuilder(args) .ConfigureWebHostDefaults(webBuilder => { webBuilder.UseStartup<Startup>(); }); } PROGRAM.CS
24. configuration
25. web.config
26. <appSettings> <add key="ApplicationName" value="MyDemoApp" /> </appSettings> <system.webServer> <defaultDocument> <files> <add value="default.aspx" /> </files> </defaultDocument> </system.webServer> WEB.CONFIG
27. web.config
28. configuration providers
29. providers SETTINGS FILES USER SECRETS ENVIRONMENT COMMAND LINE
30. appsettings.json
31. appsettings.{env}.json
32. { "FooServiceSettings": { "Url": "api.fooservice.nl", "Timeout": 60 }, "Setting1": "Value1" } APPSETTINGS.JSON
33. { "FooServiceSettings": { "Url": "dev-api.fooservice.nl", "Persist": false } } APPSETTINGS.DEVELOPMENT .JSON
34. { "FooServiceSettings": { "Url": "dev-api.fooservice.nl", "Persist": false } } APPSETTINGS.DEVELOPMENT .JSON
36. user secrets
37. <UserSecretsId>
38. <PropertyGroup> <TargetFramework>netcoreapp2.2</TargetFramework> <UserSecretsId> 18b6c74c-731d-4590-8a07-3d46a29b9228 </UserSecretsId> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.AspNetCore.App" /> </ItemGroup> MYDEMO.CSPROJ
39. ../MyDemo/ $ dotnet user-secrets list No secrets configured for this application. CLI TOOLING
40. ../MyDemo/ $ dotnet user-secrets list No secrets configured for this application. ../MyDemo/ $ dotnet user-secrets set "FooServiceSettings:ApiKey" "abcde12345" Successfully saved FooServiceSettings:ApiKey = abcde12345 to the secret store. CLI TOOLING
41. secrets.json
44. ASPNETCORE_
45. 3.0
46. DOTNET_
47. launchSettings.json
48. launch.json
49. new WebHostBuilder() .ConfigureAppConfiguration((builderContext, config) => { config.AddJsonFile("settings.json") .AddXmlFile("config.xml", optional: true) .AddInMemoryCollection( Dictionary<string,string> ) .AddCommandLine(args) }) .UseStartup<Startup>(); PROGRAM.CS
50. WebHost.CreateDefaultBuilder(args) .ConfigureAppConfiguration((builderContext, config) => { config.AddJsonFile("settings.json") .AddXmlFile("config.xml", optional: true) .AddInMemoryCollection( Dictionary<string,string> ) .AddCommandLine(args) }) .UseStartup<Startup>(); PROGRAM.CS
52. IConfiguration
53. // assuming IConfiguration is injected as _config _config.GetValue<string>("Setting1"); // "Value1" _config.GetValue<string>("FooServiceSettings:ApiKey"); // "abcde12345" DEMOCLASS.CS
54. // assuming IConfiguration is injected as _config _config.GetValue<string>("Setting1"); // "Value1" _config.GetValue<string>("FooServiceSettings:ApiKey"); // "abcde12345" var section = _config.GetSection("FooServiceSettings"); section.GetValue<int>("Timeout") // 60 DEMOCLASS.CS
56. public class FooServiceSettings { public string Url { get; set; } public string ApiKey { get; set; } public int Timeout { get; set; } public bool Persist { get; set; } } FOOSERVICESETTINGS.CS
57. // assuming IConfiguration is injected as _config var options = new FooServiceSettings(); var configSection = _config.GetSection("FooServiceSettings"); DEMOCLASS.CS configSection.Bind(options);
58. // options: {FooServiceSettings} // ApiKey [string]: "abcde12345" // Persist [bool]: false // Timeout [int]: 60 // Url [string]: dev-api.fooservice.nl DEMOCLASS.CS configSection.Bind(options);
59. IOptions<T>
60. services
61. startup
62. public class Startup { public void ConfigureServices(IServiceCollection services) { // optionally register services here... } public void Configure(IApplicationBuilder app, IHostingEnvironment env) { // register middleware and build HTTP pipeline here... } } STARTUP .CS
63. public class Startup { public void ConfigureServices(IServiceCollection services) { // optionally register services here... } public void Configure(IApplicationBuilder app, IHostingEnvironment env) { // register middleware and build HTTP pipeline here... } } STARTUP .CS
65. IServiceCollection
66. public void ConfigureServices(IServiceCollection services) {b private IConfiguration _config; public Startup(IConfiguration config) {c _config = config; }c public class Startup {a }a STARTUP .CS
67. }c STARTUP .CS public void ConfigureServices(IServiceCollection services) {b services.Configure<FooServiceSettings>(b _config.GetSection("FooServiceSettings") ); }b public class Startup {a }a
68. public class FooService { private FooServiceSettings _settings; public FooService(IOptions<FooServiceSettings> settings) { _settings = settings.Value; } } FOOSERVICE.CS
69. public class FooService { private FooServiceSettings _settings; public FooService(IOptions<FooServiceSettings> settings) { _settings = settings.Value; } } FOOSERVICE.CS
70. IOptionsSnapshot<T>
71. IOptionsMonitor<T>
73. public interface IFooService { void Connect(); List<int> GetFoos(); } IFOOSERVICE.CS public class FooService : IFooService { public void Connect() { // ... } public List<int> GetFoos() { // ... } } FOOSERVICE.CS
74. STARTUP .CS public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddScoped<IFooService, FooService>(); } }
75. STARTUP .CS public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddScoped( typeof(IFooService), typeof(FooService) ); } }
76. STARTUP .CS public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddScoped<IFooService>( new FooService( args ) ); } }
77. service lifetimes TRANSIENT SCOPED SINGLETON
78. extension methods
79. services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer( Configuration.GetConnectionString("FooConn") )b ); STARTUP .CS public class Startup {a public void ConfigureServices(IServiceCollection services) {a }a }a
80. services.AddMvc(); )b ); STARTUP .CS public class Startup {a public void ConfigureServices(IServiceCollection services) {a }a }a
81. 3.0
82. services.AddControllers(); services.AddControllersWithViews(); services.AddRazorPages(); )b ); STARTUP .CS public class Startup {a public void ConfigureServices(IServiceCollection services) {a }a }a
84. public static class FooExtensions { public static IServiceCollection AddFoo( this IServiceCollection services, string logPath) { services.AddSingleton<IFooFactory, FooFactory>(); services.AddScoped<IFooService, FooService>(); services.AddSingleton<IFooLogger>(sp => new FooLogger(logPath)); return services; } } FOOEXTENSIONS.CS
85. public static class FooExtensions { public static IServiceCollection AddFoo( this IServiceCollection services, string logPath) { services.AddSingleton<IFooFactory, FooFactory>(); services.AddScoped<IFooService, FooService>(); services.AddSingleton<IFooLogger>(sp => new FooLogger(logPath)); return services; } } FOOEXTENSIONS.CS
86. public static class FooExtensions { public static IServiceCollection AddFoo( this IServiceCollection services, string logPath) { services.AddSingleton<IFooFactory, FooFactory>(); services.AddScoped<IFooService, FooService>(); services.AddSingleton<IFooLogger>(sp => new FooLogger(logPath)); return services; } } FOOEXTENSIONS.CS
87. public static class FooExtensions { public static IServiceCollection AddFoo( this IServiceCollection services, string logPath) { services.AddSingleton<IFooFactory, FooFactory>(); services.AddScoped<IFooService, FooService>(); services.AddSingleton<IFooLogger>(sp => new FooLogger(logPath)); return services; } } FOOEXTENSIONS.CS
88. STARTUP .CS public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddMvc() .AddFoo( path ) .AddDbContext(...) .AddIdentity(...) } }
89. pipeline
90. middleware
91. Middleware 1 Middleware 2 Middleware 3 // inbound logic await next(); // inbound logic // inbound logic // outbound logic // outbound logic // outbound logic Request Response await next();
92. Middleware 1 Middleware 2 Middleware 3 // inbound logic await next(); // inbound logic // inbound logic // outbound logic // outbound logic // outbound logic Request Response await next();
93. Middleware 1 Middleware 2 Middleware 3 // inbound logic await next(); // inbound logic // inbound logic // outbound logic // outbound logic // outbound logic Request Response
94. if (env.IsDevelopment()) STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) {a }a
95. app.UseHttpsRedirection(); if (env.IsDevelopment()) {a app.UseDeveloperExceptionPage(); }a else {a app.UseHsts(); }a STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) {a }a
96. app.UseHttpsRedirection(); app.UseStaticFiles(); app.UseMvc(routes => {a routes.MapRoute( "default", "{controller=Home}/{action="Index"}/{id?}"); }); else {a app.UseHsts(); }a STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) {a }a
97. app.UseHttpsRedirection(); app.UseStaticFiles(); app.UseMvc(routes => {a routes.MapRoute( "default", "{controller=Home}/{action="Index"}/{id?}"); }); else {a app.UseHsts(); }a STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) {a }a
98. app.UseHttpsRedirection(); app.UseStaticFiles(); app.UseMvc(routes => { routes.MapRoute( "default", "{controller=Home}/{action="Index"}/{id?}"); }); else { app.UseHsts(); } STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) {a }a
100. STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) { app.Run(async (context) => { // do some logic on the context await context.Response.WriteAsync("I'm done!"); }); }
101. STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) { app.Use(async (context, next) => { // do some inbound logic on the request await next(); // do some outbound logic on the response }); }
102. STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) { app.UseHttpsRedirection(); app.Use(async (context, next) => { // do some inbound logic on the request await next(); // do some outbound logic on the response }); app.UseStaticFiles(); }
103. public async Task Invoke(HttpContext context) {a private readonly RequestDelegate _next; public FooMiddleware(RequestDelegate next) {a _next = next; }a public class FooMiddleware {b }b FOOMIDDLEWARE.CS
104. public async Task Invoke(HttpContext context) {a // do some inbound logic on the request await next(); // do some outbound logic on the response }a }a public class FooMiddleware {b }b FOOMIDDLEWARE.CS
105. FOOMIDDLEWAREEXTENSIONS.CS public static class FooMiddlewareExtensions {b public static IApplicationBuilder UseFoo( this IApplicationBuilder app) { return app.UseMiddleware<FooMiddleware>(); } }b
106. STARTUP .CS public void Configure( IApplicationBuilder app, IHostingEnvironment env) { app.UseHttpsRedirection(); app.UseFoo(); app.UseStaticFiles(); }
107. order matters people carving pumpkins pumpkins carving people
108. W H E R E T O G O F R O M H E R E dig deeper
109. leverage tools
110. keep learning
111. #startMeUp jeffrey.s.strauss@gmail.com @ j e f f r e y s t r a u ss