C# Source Generators

A list of C# Source Generators (not necessarily awesome), because I haven't found a good list yet.

C# Source Generators is a Roslyn compiler feature introduced in C#9/.NET 5. It lets C# developers inspect user code and generate new C# source files that can be added to a compilation. 

While messing around with some C code in godbolt Compiler Explorer, I kept noticing a particular funny case.

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28 videos, 192,192 views, Last updated on Jan 13, 2019
Follow along in this free course as I show you how to create an application in C# from idea through the finished product. Everything is shown on screen and in great detail. Learn how to use SQL databases, CSV text files, custom events, Linq, Lambda expressions, emailing, and more. Everything you learn will be in context of a real application.

[HttpGet("/.well-known/acme-challenge/{id}")]
public IActionResult LetsEncrypt(string id, [FromServices] IHostingEnvironment env)
{
   id = Path.GetFileName(id); // security cleaning
   var file = Path.Combine(env.ContentRootPath, ".well-known", "acme-challenge", id);
   return PhysicalFile(file, "text/plain");
}

[Route(".well-known/acme-challenge/{id}")]
public ActionResult LetsEncrypt(string id)
{
   id = Path.GetFileName(id); // security cleaning
   var file = Path.Combine(Server.MapPath("~/.well-known/acme-challenge"), id);
   return File(file, "text/plain", id);
}

Type:http
Port:80
IP address:All Unassigned

 N: Create new certificate
 M: Create new certificate with advanced options
 L: List scheduled renewals
 R: Renew scheduled
 S: Renew specific
 A: Renew *all*
 V: Revoke certificate
 C: Cancel scheduled renewal
 X: Cancel *all* scheduled renewals
 Q: Quit

 [INFO] Running in Simple mode

 1: Single binding of an IIS site
 2: SAN certificate for all bindings of an IIS site
 3: SAN certificate for all bindings of multiple IIS sites
 4: Manually input host names
 C: Cancel

 1: Default Web Site
 C: Cancel

 Choose site: 1

 * www.dotnettips.info
 * dotnettips.info

 Press enter to include all listed hosts, or type a comma-separated lists of exclusions:

 [INFO] Adding renewal for Default Web Site
 [INFO] Next renewal scheduled at 2018/7/21 4:19:20 AM

 N: Create new certificate
 M: Create new certificate with advanced options
 L: List scheduled renewals
 R: Renew scheduled
 S: Renew specific
 A: Renew *all*
 V: Revoke certificate
 C: Cancel scheduled renewal
 X: Cancel *all* scheduled renewals
 Q: Quit

 [INFO] Running in Simple mode

 1: Single binding of an IIS site
 2: SAN certificate for all bindings of an IIS site
 3: SAN certificate for all bindings of multiple IIS sites
 4: Manually input host names
 C: Cancel

 Enter comma-separated list of host names, starting with the primary one: dotnettips.info, www.dotnettips.info

1: Default Web Site
2: mysiteName
Choose site to create new bindings: 1

This lesson covers the following topics:

The State of the Octoverse | The State of the Octoverse explores a year of change with new deep dives into writing code faster, creating documentation and how we build sustainable communities on GitHub. 

When you go to https://vscode.dev, you'll be presented with a lightweight version of VS Code running fully in the browser. Open a folder on your local machine and start coding.

No install required. 

namespace DNT.IDP
{
    public class Startup
    {
        public const string TwoFactorAuthenticationScheme = "idsrv.2FA";

        public void ConfigureServices(IServiceCollection services)
        {
            // ...

            services.AddAuthentication()
                .AddCookie(authenticationScheme: TwoFactorAuthenticationScheme)
                .AddGoogle(authenticationScheme: "Google", configureOptions: options =>
                {
                    options.SignInScheme = IdentityServerConstants.ExternalCookieAuthenticationScheme;
                    options.ClientId = Configuration["Authentication:Google:ClientId"];
                    options.ClientSecret = Configuration["Authentication:Google:ClientSecret"];
                });
        }

namespace DNT.IDP.Controllers.Account
{
    [SecurityHeaders]
    [AllowAnonymous]
    public class AccountController : Controller
    {
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Login(LoginInputModel model, string button)
        {
    // ... 

            if (ModelState.IsValid)
            {
                if (await _usersService.AreUserCredentialsValidAsync(model.Username, model.Password))
                {
                    var user = await _usersService.GetUserByUsernameAsync(model.Username);
                    
                    var id = new ClaimsIdentity();
                    id.AddClaim(new Claim(JwtClaimTypes.Subject, user.SubjectId));
                    await HttpContext.SignInAsync(scheme: Startup.TwoFactorAuthenticationScheme, principal: new ClaimsPrincipal(id));

                    await _twoFactorAuthenticationService.SendTemporaryCodeAsync(user.SubjectId);

                    var redirectToAdditionalFactorUrl =
                        Url.Action("AdditionalAuthenticationFactor",
                            new
                            {
                                returnUrl = model.ReturnUrl,
                                rememberLogin = model.RememberLogin
                            });                   

                    // request for a local page
                    if (Url.IsLocalUrl(model.ReturnUrl))
                    {
                        return Redirect(redirectToAdditionalFactorUrl);
                    }

                    if (string.IsNullOrEmpty(model.ReturnUrl))
                    {
                        return Redirect("~/");
                    }

                    // user might have clicked on a malicious link - should be logged
                    throw new Exception("invalid return URL");
                }

                await _events.RaiseAsync(new UserLoginFailureEvent(model.Username, "invalid credentials"));
                ModelState.AddModelError("", AccountOptions.InvalidCredentialsErrorMessage);
            }

            // something went wrong, show form with error
            var vm = await BuildLoginViewModelAsync(model);
            return View(vm);
        }

 await HttpContext.SignInAsync(scheme: Startup.TwoFactorAuthenticationScheme, principal: new ClaimsPrincipal(id));

    public interface ITwoFactorAuthenticationService
    {
        Task SendTemporaryCodeAsync(string subjectId);
        Task<bool> IsValidTemporaryCodeAsync(string subjectId, string code);
    }

using System.ComponentModel.DataAnnotations;

namespace DNT.IDP.Controllers.Account
{
    public class AdditionalAuthenticationFactorViewModel
    {
        [Required]
        public string Code { get; set; }

        public string ReturnUrl { get; set; }

        public bool RememberLogin { get; set; }
    }
}

namespace DNT.IDP.Controllers.Account
{
    public class AccountController : Controller
    {
        [HttpGet]
        public IActionResult AdditionalAuthenticationFactor(string returnUrl, bool rememberLogin)
        {
            // create VM
            var vm = new AdditionalAuthenticationFactorViewModel
            {
                RememberLogin = rememberLogin,
                ReturnUrl = returnUrl
            };

            return View(vm);
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> AdditionalAuthenticationFactor(
            AdditionalAuthenticationFactorViewModel model)
        {
            if (!ModelState.IsValid)
            {
                return View(model);
            }

            // read identity from the temporary cookie
            var info = await HttpContext.AuthenticateAsync(Startup.TwoFactorAuthenticationScheme);
            var tempUser = info?.Principal;
            if (tempUser == null)
            {
                throw new Exception("2FA error");
            }

            // ... check code for user
            if (!await _twoFactorAuthenticationService.IsValidTemporaryCodeAsync(tempUser.GetSubjectId(), model.Code))
            {
                ModelState.AddModelError("code", "2FA code is invalid.");
                return View(model);
            }

            // login the user
            AuthenticationProperties props = null;
            if (AccountOptions.AllowRememberLogin && model.RememberLogin)
            {
                props = new AuthenticationProperties
                {
                    IsPersistent = true,
                    ExpiresUtc = DateTimeOffset.UtcNow.Add(AccountOptions.RememberMeLoginDuration)
                };
            }

            // issue authentication cookie for user
            var user = await _usersService.GetUserBySubjectIdAsync(tempUser.GetSubjectId());
            await _events.RaiseAsync(new UserLoginSuccessEvent(user.Username, user.SubjectId, user.Username));
            await HttpContext.SignInAsync(user.SubjectId, user.Username, props);

            // delete temporary cookie used for 2FA
            await HttpContext.SignOutAsync(Startup.TwoFactorAuthenticationScheme);

            if (_interaction.IsValidReturnUrl(model.ReturnUrl) || Url.IsLocalUrl(model.ReturnUrl))
            {
                return Redirect(model.ReturnUrl);
            }

            return Redirect("~/");
        }

@model AdditionalAuthenticationFactorViewModel

<div>
    <div class="page-header">
        <h1>2-Factor Authentication</h1>
    </div>

    @Html.Partial("_ValidationSummary")

    <div class="row">
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title">Input your 2FA code</h3>
            </div>
            <div class="panel-body">
                <form asp-route="Login">
                    <input type="hidden" asp-for="ReturnUrl" />
                    <input type="hidden" asp-for="RememberLogin" />

                    <fieldset>
                        <div class="form-group">
                            <label asp-for="Code"></label>
                            <input class="form-control" placeholder="Code" asp-for="Code" autofocus>
                        </div>

                        <div class="form-group">
                            <button class="btn btn-primary">Submit code</button>
                        </div>
                    </fieldset>
                </form>

            </div>
        </div>
    </div>
</div>

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00:00:00 – Start
00:00:09 – What is C#
00:01:27 – C#: Hello World
00:06:01 – C#: The Basics of Strings
00:14:35 – C#: Searching Strings
00:17:27 – C#: Numbers and Integer Math
00:22:04 – C#: Numbers and Integer Precision
00:27:32 – C#: Numbers and Decimals
00:33:10 – C#: Branches (if)
00:44:29 – C#: “Hello World” Explained
00:50:29 – C#: What are Loops?
00:57:42 – C#: Combining Branches and Loops
01:04:34 – C#: Arrays, List, and Collections
01:15:09 – C#: Sort, Search, and Index Lists
01:22:08 – C#: Lists of Other Types
01:29:51 – C#: Debugging
01:34:30 – C#: Object Oriented Programming – Objects and Classes
01:47:20 – C#: Object Oriented Programming – Methods and Members
01:56:02 – C#: Object Oriented Programming – Methods and Exceptions
02:03:00 – C#: Object Oriented Programming – Catching Exceptions