Application/GetLink/GetLinkQueryHandler.cs

@@ -18,11 +18,13 @@ namespace HN.Application
     public Task<LinkDto> Handle(GetLinkQuery request, CancellationToken cancellationToken)
     {
       var result = from link in _context.Links
+                   join user in _context.Users on link.CreatedBy equals user.Id
                    where link.Id == request.Id
                    select new LinkDto
                    {
                      Id = link.Id,
                      Url = link.Url,
+                     CreatedByName = user.UserName,
                      CreatedAt = link.CreatedAt,
                      UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
                      DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)

Application/IHNContext.cs

@@ -1,3 +1,4 @@
+using System.Linq;
 using HN.Domain;
 using Microsoft.EntityFrameworkCore;
 
@@ -10,5 +11,6 @@ namespace HN.Application
   {
     DbSet<Link> Links { get; }
     DbSet<Comment> Comments { get; }
+    IQueryable<IUser> Users { get; }
   }
 }

Application/IUser.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace HN.Application
+{
+  public interface IUser
+  {
+    Guid Id { get; }
+    string UserName { get; }
+  }
+}

Application/ListLinks/LinkDTO.cs

@@ -7,6 +7,7 @@ namespace HN.Application
     public Guid Id { get; set; }
     public string Url { get; set; }
     public DateTime CreatedAt { get; set; }
+    public string CreatedByName { get; set; }
     public int UpVotes { get; set; }
     public int DownVotes { get; set; }
 

Application/ListLinks/ListLinksQueryHandler.cs

@@ -46,10 +46,12 @@ namespace HN.Application
     public Task<LinkDto[]> Handle(ListLinksQuery request, CancellationToken cancellationToken)
     {
       var links = from link in _context.Links
+                  join user in _context.Users on link.CreatedBy equals user.Id
                   select new LinkDto
                   {
                     Id = link.Id,
                     Url = link.Url,
+                    CreatedByName = user.UserName,
                     CreatedAt = link.CreatedAt,
                     UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
                     DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)

Apps/Website/Views/Shared/_CommentForm.cshtml

@@ -2,6 +2,7 @@
 
 <div>
   <h2>Add a comment</h2>
+  @if(User.Identity.IsAuthenticated) {
     <form asp-action="Create" asp-controller="Comments" method="post">
       <input type="hidden" asp-for="@Model.LinkId" />
       <textarea asp-for="@Model.Content"></textarea>
@@ -9,4 +10,7 @@
       
       <button type="submit">Post a comment</button>
     </form>
+  } else {
+    <p>Only logged in users can comment.</p>
+  }
 </div>

Apps/Website/Views/Shared/_CommentItem.cshtml

@@ -4,8 +4,11 @@
 <div>
   👍: @Model.UpVotes / 👎: @Model.DownVotes
 </div>
-<form asp-action="Vote" asp-controller="Comments" asp-route-id="@Model.Id" method="post">
+
+@if (User.Identity.IsAuthenticated) {
+  <form asp-action="Vote" asp-controller="Comments" asp-route-id="@Model.Id" method="post">
     <input type="hidden" name="redirectTo" value="@Context.Request.Path" />
     <input type="submit" name="type" value="up" />
     <input type="submit" name="type" value="down" />
-</form>
+  </form>
+}

Apps/Website/Views/Shared/_LinkItem.cshtml

@@ -1,9 +1,11 @@
 @model HN.Application.LinkDto
 
-<a asp-action="Show" asp-controller="Links" asp-route-id="@Model.Id">@Model.Url - created at @Model.CreatedAt.ToLocalTime() (👍: @Model.UpVotes / 👎: @Model.DownVotes)</a>
+<a asp-action="Show" asp-controller="Links" asp-route-id="@Model.Id">@Model.Url - created at @Model.CreatedAt.ToLocalTime() by @Model.CreatedByName (👍: @Model.UpVotes / 👎: @Model.DownVotes)</a>
 
-<form asp-controller="Links" asp-action="Vote" asp-route-id="@Model.Id" asp-route-url="@Model.Url" method="post">
+@if(User.Identity.IsAuthenticated) {
+  <form asp-controller="Links" asp-action="Vote" asp-route-id="@Model.Id" asp-route-url="@Model.Url" method="post">
     <input type="hidden" name="redirectTo" value="@Context.Request.Path" />
     <input type="submit" name="type" value="up" />
     <input type="submit" name="type" value="down" />
-</form>
+  </form>
+}

Infrastructure/HNDbContext.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using HN.Application;
 using HN.Domain;
 using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
@@ -13,6 +14,8 @@ namespace HN.Infrastructure
     public DbSet<Link> Links { get; set; }
     public DbSet<Comment> Comments { get; set; }
 
+    IQueryable<IUser> IHNContext.Users => Users;
+
     public HNDbContext()
     {
 

Infrastructure/User.cs

@@ -1,9 +1,10 @@
 using System;
+using HN.Application;
 using Microsoft.AspNetCore.Identity;
 
 namespace HN.Infrastructure
 {
-  public sealed class User : IdentityUser<Guid>
+  public sealed class User : IdentityUser<Guid>, IUser
   {
     public User(string userName) : base(userName)
     {