Application/GetLink/GetLinkQuery.cs

@@ -4,7 +4,7 @@ using MediatR;
 
 namespace HN.Application
 {
-  public sealed class GetLinkQuery : IRequest<LinkDTO>
+  public sealed class GetLinkQuery : IRequest<LinkDto>
   {
     [Required]
     public Guid Id { get; set; }

Application/GetLink/GetLinkQueryHandler.cs

@@ -2,10 +2,11 @@ using System.Threading;
 using System.Linq;
 using System.Threading.Tasks;
 using MediatR;
+using HN.Domain;
 
 namespace HN.Application
 {
-  public sealed class GetLinkQueryHandler : IRequestHandler<GetLinkQuery, LinkDTO>
+  public sealed class GetLinkQueryHandler : IRequestHandler<GetLinkQuery, LinkDto>
   {
     private readonly IDbContext _context;
 
@@ -14,13 +15,20 @@ namespace HN.Application
       _context = context;
     }
 
-    public Task<LinkDTO> Handle(GetLinkQuery request, CancellationToken cancellationToken)
+    public Task<LinkDto> Handle(GetLinkQuery request, CancellationToken cancellationToken)
     {
       var result = from link in _context.Links
                    where link.Id == request.Id
-                   select new LinkDTO(link);
+                   select new LinkDto
+                   {
+                     Id = link.Id,
+                     Url = link.Url,
+                     CreatedAt = link.CreatedAt,
+                     UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
+                     DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)
+                   };
 
-      return Task.FromResult(result.FirstOrDefault());
+      return Task.FromResult(result.SingleOrDefault());
     }
   }
 }

Application/ListLinks/LinkDTO.cs

@@ -1,19 +1,18 @@
 using System;
-using HN.Domain;
 
 namespace HN.Application
 {
-  public sealed class LinkDTO
+  public sealed class LinkDto
   {
     public Guid Id { get; set; }
     public string Url { get; set; }
     public DateTime CreatedAt { get; set; }
+    public int UpVotes { get; set; }
+    public int DownVotes { get; set; }
 
-    public LinkDTO(Link link)
+    public LinkDto()
     {
-      Id = link.Id;
+
-      Url = link.Url;
-      CreatedAt = link.CreatedAt;
     }
   }
 }

Application/ListLinks/ListLinksQuery.cs

@@ -2,7 +2,7 @@ using MediatR;
 
 namespace HN.Application
 {
-  public sealed class ListLinksQuery : IRequest<LinkDTO[]>
+  public sealed class ListLinksQuery : IRequest<LinkDto[]>
   {
 
   }

Application/ListLinks/ListLinksQueryHandler.cs

@@ -2,10 +2,39 @@ using System.Threading;
 using System.Linq;
 using System.Threading.Tasks;
 using MediatR;
+using HN.Domain;
 
 namespace HN.Application
 {
-  public sealed class ListLinksQueryHandler : IRequestHandler<ListLinksQuery, LinkDTO[]>
+  // public static class LinkQueriesExtensions
+  // {
+  //   public static IQueryable<LinkDto> AllAsDto(this DbSet<Link> links)
+  //   {
+  //     return from link in links
+  //            select new LinkDto
+  //            {
+  //              Id = link.Id,
+  //              Url = link.Url,
+  //              CreatedAt = link.CreatedAt,
+  //              UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
+  //              DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)
+  //            };
+  //   }
+
+  //   public static IQueryable<LinkDto> ToLinkDto(this IQueryable<Link> links)
+  //   {
+  //     return links.Select(link => new LinkDto
+  //     {
+  //       Id = link.Id,
+  //       Url = link.Url,
+  //       CreatedAt = link.CreatedAt,
+  //       UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
+  //       DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)
+  //     });
+  //   }
+  // }
+
+  public sealed class ListLinksQueryHandler : IRequestHandler<ListLinksQuery, LinkDto[]>
   {
     private readonly IDbContext _context;
 
@@ -14,10 +43,17 @@ namespace HN.Application
       _context = context;
     }
 
-    public Task<LinkDTO[]> Handle(ListLinksQuery request, CancellationToken cancellationToken)
+    public Task<LinkDto[]> Handle(ListLinksQuery request, CancellationToken cancellationToken)
     {
       var links = from link in _context.Links
-                  select new LinkDTO(link);
+                  select new LinkDto
+                  {
+                    Id = link.Id,
+                    Url = link.Url,
+                    CreatedAt = link.CreatedAt,
+                    UpVotes = link.Votes.Count(v => v.Type == VoteType.Up),
+                    DownVotes = link.Votes.Count(v => v.Type == VoteType.Down)
+                  };
 
       return Task.FromResult(links.ToArray());
     }

Apps/Website/Views/Links/Index.cshtml

@@ -1,4 +1,4 @@
-@model HN.Application.LinkDTO[]
+@model HN.Application.LinkDto[]
 @{
   ViewData["Title"] = "Latest Links";
 }

Apps/Website/Views/Links/Show.cshtml

@@ -1,3 +1,3 @@
-@model HN.Application.LinkDTO
+@model HN.Application.LinkDto
 
 <partial name="_LinkItem" model="@Model" />

Apps/Website/Views/Links/_LinkItem.cshtml

@@ -1,3 +1,3 @@
-@model HN.Application.LinkDTO
+@model HN.Application.LinkDto
 
-<a asp-action="Show" asp-controller="Links" asp-route-id="@Model.Id">@Model.Url - created at @Model.CreatedAt.ToLocalTime()</a>
+<a asp-action="Show" asp-controller="Links" asp-route-id="@Model.Id">@Model.Url - created at @Model.CreatedAt.ToLocalTime() (👍: @Model.UpVotes / 👎: @Model.DownVotes)</a>

Apps/Website/appsettings.Development.json

@@ -3,7 +3,8 @@
     "LogLevel": {
       "Default": "Information",
       "Microsoft": "Warning",
-      "Microsoft.Hosting.Lifetime": "Information"
+      "Microsoft.Hosting.Lifetime": "Information",
+      "Microsoft.EntityFrameworkCore": "Information"
     }
   }
 }

Domain/Link.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 namespace HN.Domain
 {
@@ -7,12 +8,15 @@ namespace HN.Domain
     public Guid Id { get; }
     public string Url { get; }
     public DateTime CreatedAt { get; }
+    private List<Vote> _votes;
+    public IReadOnlyList<Vote> Votes { get { return _votes; } }
 
     private Link(string url)
     {
       this.Id = Guid.NewGuid();
       this.CreatedAt = DateTime.UtcNow;
       this.Url = url;
+      this._votes = new List<Vote>();
     }
 
     public static Link FromUrl(string url)

Domain/Vote.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace HN.Domain
+{
+  public sealed class Vote
+  {
+    public VoteType Type { get; private set; }
+    public DateTime CreatedAt { get; private set; }
+
+    public Vote(VoteType type)
+    {
+      Type = type;
+      CreatedAt = DateTime.UtcNow;
+    }
+  }
+}

Domain/VoteType.cs

@@ -0,0 +1,8 @@
+namespace HN.Domain
+{
+  public enum VoteType
+  {
+    Up,
+    Down
+  }
+}

Infrastructure/EntityTypes/LinkEntityType.cs

@@ -13,6 +13,12 @@ namespace HN.Infrastructure.EntityTypes
       builder.Property(o => o.Url).IsRequired().HasMaxLength(500);
       builder.Property(o => o.CreatedAt).IsRequired();
       builder.HasIndex(o => o.Url).IsUnique();
+
+      builder.HasMany<Vote>(o => o.Votes)
+        .WithOne()
+        .HasForeignKey("LinkId")
+        .OnDelete(DeleteBehavior.Cascade)
+        .IsRequired();
     }
   }
 }

Infrastructure/EntityTypes/VoteEntityType.cs

@@ -0,0 +1,18 @@
+using HN.Domain;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace HN.Infrastructure.EntityTypes
+{
+  public sealed class VoteEntityType : IEntityTypeConfiguration<Vote>
+  {
+    public void Configure(EntityTypeBuilder<Vote> builder)
+    {
+      builder.ToTable("link_votes");
+      builder.HasKey("LinkId");
+      builder.Property(o => o.Type).IsRequired();
+      builder.Property(o => o.CreatedAt).IsRequired();
+    }
+  }
+
+}

Infrastructure/HNDbContext.cs

@@ -1,11 +1,13 @@
 using HN.Application;
 using HN.Domain;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
 
 namespace HN.Infrastructure
 {
   public sealed class HNDbContext : DbContext, IDbContext
   {
+    private readonly ILoggerFactory _loggerFactory;
     public DbSet<Link> Links { get; set; }
 
     public HNDbContext()
@@ -13,9 +15,9 @@ namespace HN.Infrastructure
 
     }
 
-    public HNDbContext(DbContextOptions<HNDbContext> options) : base(options)
+    public HNDbContext(DbContextOptions<HNDbContext> options, ILoggerFactory loggerFactory) : base(options)
     {
-
+      _loggerFactory = loggerFactory;
     }
 
     protected override void OnModelCreating(ModelBuilder modelBuilder) => modelBuilder.ApplyConfigurationsFromAssembly(this.GetType().Assembly);
@@ -27,6 +29,8 @@ namespace HN.Infrastructure
       {
         optionsBuilder.UseSqlite("Data Source=:memory:");
       }
+
+      optionsBuilder.UseLoggerFactory(_loggerFactory);
     }
   }
 }

Infrastructure/Migrations/20201210094301_CreateLinkVote.Designer.cs

@@ -0,0 +1,75 @@
+// <auto-generated />
+using System;
+using HN.Infrastructure;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+namespace Infrastructure.Migrations
+{
+    [DbContext(typeof(HNDbContext))]
+    [Migration("20201210094301_CreateLinkVote")]
+    partial class CreateLinkVote
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "5.0.0");
+
+            modelBuilder.Entity("HN.Domain.Link", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Url")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Url")
+                        .IsUnique();
+
+                    b.ToTable("links");
+                });
+
+            modelBuilder.Entity("HN.Domain.Vote", b =>
+                {
+                    b.Property<Guid>("LinkId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("LinkId");
+
+                    b.ToTable("link_votes");
+                });
+
+            modelBuilder.Entity("HN.Domain.Vote", b =>
+                {
+                    b.HasOne("HN.Domain.Link", null)
+                        .WithMany("Votes")
+                        .HasForeignKey("LinkId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HN.Domain.Link", b =>
+                {
+                    b.Navigation("Votes");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Infrastructure/Migrations/20201210094301_CreateLinkVote.cs

@@ -0,0 +1,36 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Infrastructure.Migrations
+{
+    public partial class CreateLinkVote : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "link_votes",
+                columns: table => new
+                {
+                    LinkId = table.Column<Guid>(type: "TEXT", nullable: false),
+                    Type = table.Column<int>(type: "INTEGER", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "TEXT", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_link_votes", x => x.LinkId);
+                    table.ForeignKey(
+                        name: "FK_link_votes_links_LinkId",
+                        column: x => x.LinkId,
+                        principalTable: "links",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "link_votes");
+        }
+    }
+}

Infrastructure/Migrations/HNDbContextModelSnapshot.cs

@@ -37,6 +37,36 @@ namespace Infrastructure.Migrations
 
                     b.ToTable("links");
                 });
+
+            modelBuilder.Entity("HN.Domain.Vote", b =>
+                {
+                    b.Property<Guid>("LinkId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("LinkId");
+
+                    b.ToTable("link_votes");
+                });
+
+            modelBuilder.Entity("HN.Domain.Vote", b =>
+                {
+                    b.HasOne("HN.Domain.Link", null)
+                        .WithMany("Votes")
+                        .HasForeignKey("LinkId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("HN.Domain.Link", b =>
+                {
+                    b.Navigation("Votes");
+                });
 #pragma warning restore 612, 618
         }
     }