namespace DNT.IDP
{
    public static class Config
    {
        public static List<TestUser> GetUsers()
        {
            return new List<TestUser>
            {
                new TestUser
                {
                    Username = "User 1",
                    // ...

                    Claims = new List<Claim>
                    {
    // ...
                        new Claim("subscriptionlevel", "PayingUser"),
                        new Claim("country", "ir")
                    }
                },
                new TestUser
                {
                    Username = "User 2",
// ...

                    Claims = new List<Claim>
                    {
    // ...
                        new Claim("subscriptionlevel", "FreeUser"),
                        new Claim("country", "be")
                    }
                }
            };
        }

namespace DNT.IDP
{
    public static class Config
    {
        // identity-related resources (scopes)
        public static IEnumerable<IdentityResource> GetIdentityResources()
        {
            return new List<IdentityResource>
            {
   // ...     
                new IdentityResource(
                    name: "country",
                    displayName: "The country you're living in",
                    claimTypes: new List<string> { "country" }),
                new IdentityResource(
                    name: "subscriptionlevel",
                    displayName: "Your subscription level",
                    claimTypes: new List<string> { "subscriptionlevel" })
            };
        }

namespace DNT.IDP
{
    public static class Config
    {
        public static IEnumerable<Client> GetClients()
        {
            return new List<Client>
            {
                new Client
                {
                    ClientName = "Image Gallery",
// ...
                    AllowedScopes =
                    {
    // ...
                        "country",
                        "subscriptionlevel"
                    }
// ...
                }
             };
        }
    }

options.Scope.Add("subscriptionlevel");
options.Scope.Add("country");

options.ClaimActions.MapUniqueJsonKey(claimType: "role", jsonKey: "role");
options.ClaimActions.MapUniqueJsonKey(claimType: "subscriptionlevel", jsonKey: "subscriptionlevel");
options.ClaimActions.MapUniqueJsonKey(claimType: "country", jsonKey: "country");

namespace ImageGallery.MvcClient.WebApp
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthorization(options =>
            {
                options.AddPolicy(
                   name: "CanOrderFrame",
                   configurePolicy: policyBuilder =>
                    {
                        policyBuilder.RequireAuthenticatedUser();
                        policyBuilder.RequireClaim(claimType: "country", requiredValues: "ir");
                        policyBuilder.RequireClaim(claimType: "subscriptionlevel", requiredValues: "PayingUser");
                    });
            });

@if(User.IsInRole("PayingUser"))
{
  <li><a asp-area="" asp-controller="Gallery" asp-action="AddImage">Add an image</a></li>
  <li><a asp-area="" asp-controller="Gallery" asp-action="OrderFrame">Order a framed picture</a></li>
}

@using Microsoft.AspNetCore.Authorization
@inject IAuthorizationService AuthorizationService

@if (User.IsInRole("PayingUser"))
{
  <li><a asp-area="" asp-controller="Gallery" asp-action="AddImage">Add an image</a></li>
}
@if ((await AuthorizationService.AuthorizeAsync(User, "CanOrderFrame")).Succeeded)
{
  <li><a asp-area="" asp-controller="Gallery" asp-action="OrderFrame">Order a framed picture</a></li>
}

namespace ImageGallery.MvcClient.WebApp.Controllers
{
    [Authorize]
    public class GalleryController : Controller
    {
        [Authorize(Policy = "CanOrderFrame")]
        public async Task<IActionResult> OrderFrame()
        {

using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.Logging;

namespace ImageGallery.WebApi.Services
{
    public class MustOwnImageRequirement : IAuthorizationRequirement
    {
    }

    public class MustOwnImageHandler : AuthorizationHandler<MustOwnImageRequirement>
    {
        private readonly IImagesService _imagesService;
        private readonly ILogger<MustOwnImageHandler> _logger;

        public MustOwnImageHandler(
            IImagesService imagesService,
            ILogger<MustOwnImageHandler> logger)
        {
            _imagesService = imagesService;
            _logger = logger;
        }

        protected override async Task HandleRequirementAsync(
            AuthorizationHandlerContext context, MustOwnImageRequirement requirement)
        {
            var filterContext = context.Resource as AuthorizationFilterContext;
            if (filterContext == null)
            {
                context.Fail();
                return;
            }

            var imageId = filterContext.RouteData.Values["id"].ToString();
            if (!Guid.TryParse(imageId, out Guid imageIdAsGuid))
            {
                _logger.LogError($"`{imageId}` is not a Guid.");
                context.Fail();
                return;
            }

            var subClaim = context.User.Claims.FirstOrDefault(c => c.Type == "sub");
            if (subClaim == null)
            {
                _logger.LogError($"User.Claims don't have the `sub` claim.");
                context.Fail();
                return;
            }

            var ownerId = subClaim.Value;
            if (!await _imagesService.IsImageOwnerAsync(imageIdAsGuid, ownerId))
            {
                _logger.LogError($"`{ownerId}` is not the owner of `{imageIdAsGuid}` image.");
                context.Fail();
                return;
            }

            // all checks out
            context.Succeed(requirement);
        }
    }
}

<Project Sdk="Microsoft.NET.Sdk">
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Authorization" Version="2.1.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.Abstractions" Version="2.1.1.0" />
  </ItemGroup>
</Project>

public class MustOwnImageRequirement : IAuthorizationRequirement
{
}

namespace ImageGallery.WebApi.WebApp
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthorization(authorizationOptions =>
            {
                authorizationOptions.AddPolicy(
                   name: "MustOwnImage",
                   configurePolicy: policyBuilder =>
                    {
                        policyBuilder.RequireAuthenticatedUser();
                        policyBuilder.AddRequirements(new MustOwnImageRequirement());
                    });
            });
            services.AddScoped<IAuthorizationHandler, MustOwnImageHandler>();

[Authorize(Policy ="MustOwnImage")]

namespace ImageGallery.WebApi.WebApp.Controllers
{
    [Route("api/images")]
    [Authorize]
    public class ImagesController : Controller
    {
        [HttpGet("{id}", Name = "GetImage")]
        [Authorize("MustOwnImage")]
        public async Task<IActionResult> GetImage(Guid id)
        {
        }

        [HttpDelete("{id}")]
        [Authorize("MustOwnImage")]
        public async Task<IActionResult> DeleteImage(Guid id)
        {
        }

        [HttpPut("{id}")]
        [Authorize("MustOwnImage")]
        public async Task<IActionResult> UpdateImage(Guid id, [FromBody] ImageForUpdateModel imageForUpdate)
        {
        }
    }
}

A Tour of Go (golang) for the C# Developer

Learning other programming languages enhances our work in our primary language. From the perspective of a C# developer, the Go language (golang) has many interesting ideas. Go is opinionated on some things (such as where curly braces go and what items are capitalized). Declaring an unused variable causes a compile failure; the use of "blank identifiers" (or "discards" in C#) are common. Concurrency is baked right in to the language through goroutines and channels. Programming by exception is discouraged; it's actually called a "panic" in Go. Instead, errors are treated as states to be handled like any other data state. We'll explore these features (and others) by building an application that uses concurrent operations to get data from a service. These ideas make us think about the way we program and how we can improve our day-to-day work (in C# or elsewhere).

0:00 Welcome to Go
2:40 Step 1: Basics
12:20 Step 2: Calling a web service
23:35 Step 3: Parsing JSON
36:26 Step 4: "for" loops
41:00 Step 5: Interfaces and methods
50:05 Step 6: Time and Args
55:10 Step 7: Concurrency
1:07:10 Step 8: Errors
1:14:40 Step 9: Concurrency and errors
1:24:35 Where to go next 

using System;
using System.Net.Http;
using System.Threading.Tasks;

namespace HttpClientTips.LargeFiles
{
    class Program
    {
        private static readonly HttpClient _client = new HttpClient();

        static async Task Main(string[] args)
        {
            var bytes = await DownloadLargeFileAsync();
        }

        public static async Task<byte[]> DownloadLargeFileAsync()
        {
            Console.WriteLine("Downloading a 4K content - too much bytes.");
            var response = await _client.GetAsync("http://downloads.4ksamples.com/downloads/sample-Elysium.2013.2160p.mkv");
            var bytes = await response.Content.ReadAsByteArrayAsync();
            return bytes;
        }
    }
}

private static readonly HttpClient _client = new HttpClient
{
    Timeout = Timeout.InfiniteTimeSpan
};

namespace HttpClientTips.LargeFiles
{
    class Program
    {
        private static readonly HttpClient _client = new HttpClient
        {
            Timeout = Timeout.InfiniteTimeSpan
        };

        static async Task Main(string[] args)
        {
            await DownloadLargeFileAsync();
        }

        public static async Task DownloadLargeFileAsync()
        {
            Console.WriteLine("Downloading a 4K content. too much bytes.");
            var response = await _client.GetAsync("http://downloads.4ksamples.com/downloads/sample-Elysium.2013.2160p.mkv");
            using (var streamToReadFrom = await response.Content.ReadAsStreamAsync())
            {
                string fileToWriteTo = Path.GetTempFileName();
                Console.WriteLine($"Save path: {fileToWriteTo}");
                using (var streamToWriteTo = File.Open(fileToWriteTo, FileMode.Create))
                {
                    await streamToReadFrom.CopyToAsync(streamToWriteTo);
                }
            }
        }
    }
}

private static readonly HttpClientHandler _handler = new HttpClientHandler
{
    MaxConnectionsPerServer = int.MaxValue, // default for .NET Core
    UseDefaultCredentials = true
};
private static readonly HttpClient _client = new HttpClient(_handler)
{
    Timeout = Timeout.InfiniteTimeSpan
};

پیش زمینه: سیستم عضویت در ASP.NET

[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
    if (ModelState.IsValid)
    {
        var user = new ApplicationUser() { UserName = model.UserName };
        var result = await UserManager.CreateAsync(user, model.Password);
        if (result.Succeeded)
        {
            await SignInAsync(user, isPersistent: false);
            return RedirectToAction("Index", "Home");
        }
        else
        {
            AddErrors(result);
        }
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
    if (ModelState.IsValid)
    {
        var user = new ApplicationUser() { UserName = model.UserName };
        var result = await UserManager.CreateAsync(user, model.Password);
        if (result.Succeeded)
        {
            await SignInAsync(user, isPersistent: false);
            return RedirectToAction("Index", "Home");
        }
        else
        {
            AddErrors(result);
        }
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

private async Task SignInAsync(ApplicationUser user, bool isPersistent)
{
    AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie);

    var identity = await UserManager.CreateIdentityAsync(
       user, DefaultAuthenticationTypes.ApplicationCookie);

    AuthenticationManager.SignIn(
       new AuthenticationProperties() { 
          IsPersistent = isPersistent 
       }, identity);
}

// POST: /Account/LogOff
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult LogOff()
{
    AuthenticationManager.SignOut();
    return RedirectToAction("Index", "Home");
}