2nd lecture for Binary Studio Academy PRO course about .NET Core by Max Goncharuk (.NET developer at Binary Studio) binary-studio.com

1. ASP.NET Core
binary-studio.com

2. Contents
1. Intro
2. Startup
3. Middleware
4. Logging
5. Static files
6. Routing
7. Authentication
8. Configuration

3. Intro

4. What is ASP.NET Core?
leaner and modular architecture
tighter security
reduced servicing
improved performance
pay-for-what-you-use model.

5. Why is ASP.NET Core?
Integration of modern client-side frameworks and development workflows
A cloud-ready environment-based configuration system
Built-in dependency injection
New light-weight and modular HTTP request pipeline (No System.Web.dll
Ability to host on IIS or self-host in your own process
Built on .NET Core, which supports true side-by-side app versioning
Ships entirely as NuGet packages

6. public static void Main(string[] args)
{
var host = new WebHostBuilder()
.UseKestrel() //
.UseServer("Microsoft.AspNet.Server.Kestrel")
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
host.Run();
}

7. Startup

8. Configure - how the ASP.NET application will respond to individual HTTP
requests.
ConfigureServices - method for configuring services that are used by your
application.

9. Configure
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddConsole(Configuration.GetSection("Logging"));
loggerFactory.AddDebug();
if (!env.IsDevelopment())
{
app.UseExceptionHandler("/Home/Error");
}
app.UseStaticFiles();
app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
});
}

10. ConfigureServices
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
services.AddIdentity<ApplicationUser, IdentityRole>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
services.AddMvc();
// Add application services.
services.AddTransient<IEmailSender, AuthMessageSender>();
services.AddTransient<ISmsSender, AuthMessageSender>();
}

11. Middleware

12. Pipeline with IApplicationBuilder
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseExceptionHandler("/Home/Error"); // Middleware 1
app.UseStaticFiles(); // Middleware 2
app.UseIdentity(); // Middleware 3
app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
}); // Middleware 4
}

13. Custom pipeline
public void ConfigureLogInline(IApplicationBuilder app, ILoggerFactory loggerfactory)
{
loggerfactory.AddConsole(minLevel: LogLevel.Information);
var logger = loggerfactory.CreateLogger(_environment);
app.Use(async (context, next) =>
{
logger.LogInformation("Handling request.");
await next.Invoke(); // Comment it to terminate the
pipeline
logger.LogInformation("Finished handling request.");
});
app.Run(async context =>
{
await context.Response.WriteAsync("Hello from " + _environment);
});
}

14. Logging

15. Logging
Interfaces:
ILoggerFactory
ILogger
Extension methods:
AddConsole
AddDebug
AddTraceSource

16. Simple logging
[Route("api/[controller]")]
public class TodoController : Controller
{
private readonly ITodoRepository _todoRepository;
private readonly ILogger<TodoController> _logger;
public TodoController(ITodoRepository todoRepository,
ILogger<TodoController> logger)
{
_todoRepository = todoRepository;
_logger = logger;
}
[HttpGet]
public IEnumerable<TodoItem> GetAll()
{
_logger.LogInformation(LoggingEvents.LIST_ITEMS, "Listing all items");
return _todoRepository.GetAll();
}
}

17. Thirdparty Providers
elmah.io - provider for the elmah.io service
Loggr - provider for the Loggr service
NLog - provider for the NLog library
Serilog - provider for the Serilog library
your own

18. Static Files

19. Set directory to content:
public static void Main(string[] args)
{
var host = new WebHostBuilder()
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
host.Run();
}
Set static files to pipeline:
public void Configure(IApplicationBuilder app,
IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseStaticFiles();
app.UseStaticFiles(new StaticFileOptions()
{
FileProvider = new PhysicalFileProvider(
Path.Combine(Directory.GetCurrentDirectory(),
@"MyStaticFiles")),
RequestPath = new PathString("/StaticFiles")
});
}

20. Content type mapping
public void Configure(IApplicationBuilder app)
{
// Set up custom content types -associating file extension to MIME type
var provider = new FileExtensionContentTypeProvider();
// Add new mappings
provider.Mappings[".myapp"] = "application/x-msdownload";
provider.Mappings[".htm3"] = "text/html";
provider.Mappings[".image"] = "image/png";
// Replace an existing mapping
provider.Mappings[".rtf"] = "application/x-msdownload";
// Remove MP4 videos.
provider.Mappings.Remove(".mp4");
app.UseStaticFiles(new StaticFileOptions()
{
FileProvider = new PhysicalFileProvider(
Path.Combine(Directory.GetCurrentDirectory(), @"wwwrootimages")),
RequestPath = new PathString("/MyImages"),
ContentTypeProvider = provider
});
}

21. Routing

22. URL Matching
Request
Route 1
Route 2
Route N
RouterMiddleware
.RouteAsync()
Handle()
Next()

23. Mapping
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
routes.MapRoute(
name: "us_english_products",
template: "en-US/Products/{id}",
defaults: new { controller = "Products", action = "Details" },
constraints: new { id = new IntRouteConstraint() },
dataTokens: new { locale = "en-US" });

24. Routing Middleware
public void ConfigureServices(
IServiceCollection services)
{
services.AddRouting();
}
public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
{
var trackPackageRouteHandler = new RouteHandler(context =>
{
var routeValues = context.GetRouteData().Values;
return context.Response.WriteAsync(
$"Hello! Route values: {string.Join(", ", routeValues)}");
});
var routeBuilder = new RouteBuilder(app, trackPackageRouteHandler);
routeBuilder.MapRoute(
"Track Package Route",
"package/{operation:regex(^track|create|detonate$)}/{id:int}");
routeBuilder.MapGet("hello/{name}", context =>
{
var name = context.GetRouteValue("name");
return context.Response.WriteAsync($"Hi, {name}!");
});
var routes = routeBuilder.Build();
app.UseRouter(routes);

25. RouteBuilder methods
MapRoute
MapGet
MapPost
MapPut
MapDelete
MapVerb

26. Authentication

27. Identity
// Authentication should be set to Individual User Accounts
// ConfigureServices
services.AddIdentity<ApplicationUser, IdentityRole>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
// Configure
app.UserIdentity();
// Manage users
UserManager<ApplicationUser> _usermanager;
// Manage sign in/sign out
SignInManage<ApplicationUser> _signinmanager;

28. Facebook, Twitter, Google Providers
app.UseFacebookAuthentication(new FacebookOptions()
{
AppId = Configuration["Authentication:Facebook:AppId"],
AppSecret = Configuration["Authentication:Facebook:AppSecret"]
});
// Other providers use similar approach

29. Other Features
Two-factor authentication with SMS
Supporting Third Party Clients using OAuth 2.0
Azure Active Directory
Securing ASP.NET Core apps with IdentityServer4

30. Configuration

31. var builder = new ConfigurationBuilder();
builder.SetBasePath(Directory.GetCurrentDirectory());
builder.AddJsonFile("appsettings.json");
builder.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);
builder.AddCommandLine(args);
var connectionStringConfig = builder.Build();
var str = connectionStringConfig.GetConnectionString("DefaultConnection")

32. IOptions
// ConfigureServices
services.AddOptions();
services.Configure<MyOptions>(Configuration);
// Configure MyOptions using code
services.Configure<MyOptions>(myOptions =>
{
myOptions.Option1 = "value1_from_action";
myOptions.Option2 = connectionStringConfig.GetConnectionString("DefaultConnection");
});
public class HomeController : Controller
{
private readonly IOptions<MyOptions> _optionsAccessor;
public HomeController(IOptions<MyOptions> optionsAccessor)
{
_optionsAccessor = optionsAccessor;
}
// GET: /<controller>/
public IActionResult Index() => View(_optionsAccessor.Value);
}
public class MyOptions
{
public string Option1 { get; set;
}
public string Option2 { get; set;
}
}

33. Error Handling

34. Exception Handling Page
// Configure
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Error");
}

35. Status Code Pages
// Configure
app.UseStatusCodePages();
app.UseStatusCodePages(context =>
context.HttpContext.Response.SendAsync("Handler, status code: " +
context.HttpContext.Response.StatusCode, "text/plain"));
app.UseStatusCodePages("text/plain", "Response, status code: {0}");
app.UseStatusCodePagesWithRedirects("~/errors/{0}");
app.UseStatusCodePagesWithReExecute("/errors/{0}");

36. ASP.NET MVC Handling
Exception filters
Model validation

37. Swagger

38. Swagger is a machine readable representation of a RESTful API
Swashbuckle is an open source project for generating Swagger documents for
Web APIs

39. Set Up
// Install package
Install-Package Swashbuckle -Pre
Add Swashbuckle to project.json: "Swashbuckle": "6.0.0-beta902"
// Configure
// Enable middleware to serve generated Swagger as a JSON endpoint
app.UseSwagger();
// Enable middleware to serve swagger-ui assets (HTML, JS, CSS etc.)
app.UseSwaggerUi();
// ConfigureServices
// Inject an implementation of ISwaggerProvider with defaulted settings applied
services.AddSwaggerGen();