Nullable types

src/Directory.Build.props

@@ -13,6 +13,7 @@
         <AnalysisLevel>latest</AnalysisLevel>
         <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
 			  <NuGetAuditLevel>critical</NuGetAuditLevel>
+			  <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <PropertyGroup Condition="'$(Configuration)' == 'Release'">

src/LinkDotNet.Blog.Domain/BlogPost.cs

@@ -10,33 +10,29 @@ namespace LinkDotNet.Blog.Domain;
 
 public sealed partial class BlogPost : Entity
 {
-    private BlogPost()
-    {
-    }
-
-    public string Title { get; private set; }
+    public string Title { get; private set; } = default!;
 
-    public string ShortDescription { get; private set; }
+    public string ShortDescription { get; private set; } = default!;
 
-    public string Content { get; private set; }
+    public string Content { get; private set; } = default!;
 
-    public string PreviewImageUrl { get; private set; }
+    public string PreviewImageUrl { get; private set; } = default!;
 
-    public string PreviewImageUrlFallback { get; private set; }
+    public string? PreviewImageUrlFallback { get; private set; }
 
     public DateTime UpdatedDate { get; private set; }
 
     public DateTime? ScheduledPublishDate { get; private set; }
 
-    public IList<string> Tags { get; private set; }
+    public IList<string> Tags { get; private set; } = [];
 
     public bool IsPublished { get; private set; }
 
     public int Likes { get; set; }
 
     public bool IsScheduled => ScheduledPublishDate is not null;
 
-    public string TagsAsString => string.Join(",", Tags ?? []);
+    public string TagsAsString => string.Join(",", Tags);
 
     public int ReadingTimeInMinutes { get; private set; }
 
@@ -95,8 +91,8 @@ public static BlogPost Create(
         bool isPublished,
         DateTime? updatedDate = null,
         DateTime? scheduledPublishDate = null,
-        IEnumerable<string> tags = null,
-        string previewImageUrlFallback = null)
+        IEnumerable<string>? tags = null,
+        string? previewImageUrlFallback = null)
     {
         if (scheduledPublishDate is not null && isPublished)
         {

src/LinkDotNet.Blog.Domain/BlogPostRecord.cs

@@ -4,7 +4,7 @@ namespace LinkDotNet.Blog.Domain;
 
 public class BlogPostRecord : Entity
 {
-    public string BlogPostId { get; init; }
+    public required string BlogPostId { get; init; }
 
     public DateOnly DateClicked { get; init; }
 

src/LinkDotNet.Blog.Domain/Entity.cs

@@ -2,5 +2,5 @@
 
 public abstract class Entity
 {
-    public string Id { get; set; }
+    public string Id { get; set; } = default!;
 }

src/LinkDotNet.Blog.Domain/Enumeration.cs

@@ -10,10 +10,6 @@ public abstract class Enumeration<TEnumeration>
    where TEnumeration : Enumeration<TEnumeration>
 #pragma warning restore
 {
-    protected Enumeration()
-    {
-    }
-
     protected Enumeration(string key)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(key);
@@ -35,7 +31,7 @@ public static TEnumeration Create(string key)
 
     public override int GetHashCode() => Key.GetHashCode(StringComparison.Ordinal);
 
-    public override bool Equals(object obj) => obj?.GetType() == typeof(TEnumeration) && ((TEnumeration)obj).Key == Key;
+    public override bool Equals(object? obj) => obj?.GetType() == typeof(TEnumeration) && ((TEnumeration)obj).Key == Key;
 
     public override string ToString() => Key;
 
@@ -46,7 +42,7 @@ private static FrozenSet<TEnumeration> GetEnumerations()
         return enumerationType
             .GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.DeclaredOnly)
             .Where(info => info.FieldType == typeof(TEnumeration))
-            .Select(info => (TEnumeration)info.GetValue(null))
+            .Select(info => (TEnumeration)info.GetValue(null)!)
             .ToFrozenSet();
     }
 }

src/LinkDotNet.Blog.Domain/Introduction.cs

@@ -4,9 +4,9 @@ public sealed record Introduction
 {
     public const string IntroductionSection = "Introduction";
 
-    public string BackgroundUrl { get; init; }
+    public string? BackgroundUrl { get; init; }
 
-    public string ProfilePictureUrl { get; init; }
+    public required string ProfilePictureUrl { get; init; }
 
-    public string Description { get; init; }
+    public required string Description { get; init; }
 }

src/LinkDotNet.Blog.Domain/LinkDotNet.Blog.Domain.csproj

@@ -2,7 +2,7 @@
 
     <PropertyGroup>
         <TargetFramework>net9.0</TargetFramework>
-        <Nullable>disable</Nullable>
+        <Nullable>enable</Nullable>
         <AssemblyName>LinkDotNet.Blog.Domain</AssemblyName>
         <RootNamespace>LinkDotNet.Blog.Domain</RootNamespace>
     </PropertyGroup>

src/LinkDotNet.Blog.Domain/ProficiencyLevel.cs

@@ -6,12 +6,8 @@ public sealed class ProficiencyLevel : Enumeration<ProficiencyLevel>
     public static readonly ProficiencyLevel Proficient = new(nameof(Proficient));
     public static readonly ProficiencyLevel Expert = new(nameof(Expert));
 
-    private ProficiencyLevel()
-    {
-    }
-
     private ProficiencyLevel(string key)
         : base(key)
     {
     }
-}
+}

src/LinkDotNet.Blog.Domain/ProfileInformation.cs

@@ -3,9 +3,10 @@
 public sealed record ProfileInformation
 {
     public const string ProfileInformationSection = "ProfileInformation";
-    public string Name { get; init; }
 
-    public string Heading { get; init; }
+    public required string Name { get; init; }
 
-    public string ProfilePictureUrl { get; init; }
+    public required string Heading { get; init; }
+
+    public required string ProfilePictureUrl { get; init; }
 }

src/LinkDotNet.Blog.Domain/ProfileInformationEntry.cs

@@ -6,11 +6,7 @@ namespace LinkDotNet.Blog.Domain;
 [DebuggerDisplay("{Content} with sort order {SortOrder}")]
 public sealed class ProfileInformationEntry : Entity
 {
-    private ProfileInformationEntry()
-    {
-    }
-
-    public string Content { get; private init; }
+    public string Content { get; private init; } = default!;
 
     public int SortOrder { get; set; }
 

src/LinkDotNet.Blog.Domain/Skill.cs

@@ -4,27 +4,23 @@ namespace LinkDotNet.Blog.Domain;
 
 public sealed class Skill : Entity
 {
-    private Skill()
-    {
-    }
-
-    private Skill(string name, string iconUrl, string capability, ProficiencyLevel proficiencyLevel)
+    private Skill(string name, string? iconUrl, string capability, ProficiencyLevel proficiencyLevel)
     {
         IconUrl = iconUrl;
         Name = name;
         Capability = capability;
         ProficiencyLevel = proficiencyLevel;
     }
 
-    public string IconUrl { get; private set; }
+    public string? IconUrl { get; private set; }
 
     public string Name { get; private set; }
 
     public string Capability { get; private set; }
 
     public ProficiencyLevel ProficiencyLevel { get; private set; }
 
-    public static Skill Create(string name, string iconUrl, string capability, string proficiencyLevel)
+    public static Skill Create(string name, string? iconUrl, string capability, string proficiencyLevel)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(name);
         ArgumentException.ThrowIfNullOrWhiteSpace(capability);

src/LinkDotNet.Blog.Domain/Social.cs

@@ -4,15 +4,15 @@ public sealed record Social
 {
     public const string SocialSection = "Social";
 
-    public string LinkedinAccountUrl { get; init; }
+    public string? LinkedinAccountUrl { get; init; }
 
     public bool HasLinkedinAccount => !string.IsNullOrEmpty(LinkedinAccountUrl);
 
-    public string GithubAccountUrl { get; init; }
+    public string? GithubAccountUrl { get; init; }
 
     public bool HasGithubAccount => !string.IsNullOrEmpty(GithubAccountUrl);
 
-    public string TwitterAccountUrl { get; init; }
+    public string? TwitterAccountUrl { get; init; }
 
     public bool HasTwitterAccount => !string.IsNullOrEmpty(TwitterAccountUrl);
-}
+}

src/LinkDotNet.Blog.Domain/Talk.cs

@@ -4,15 +4,11 @@ namespace LinkDotNet.Blog.Domain;
 
 public sealed class Talk : Entity
 {
-    private Talk()
-    {
-    }
-
-    public string PresentationTitle { get; private set; }
+    public string PresentationTitle { get; private set; } = default!;
 
-    public string Place { get; private set; }
+    public string Place { get; private set; } = default!;
 
-    public string Description { get; private set; }
+    public string Description { get; private set; } = default!;
 
     public DateTime PublishedDate { get; private set; }
 

src/LinkDotNet.Blog.Domain/UserRecord.cs

@@ -6,5 +6,5 @@ public sealed class UserRecord : Entity
 {
     public DateOnly DateClicked { get; init; }
 
-    public string UrlClicked { get; init; }
+    public required string UrlClicked { get; init; }
 }

src/LinkDotNet.Blog.Infrastructure/LinkDotNet.Blog.Infrastructure.csproj

@@ -4,6 +4,7 @@
         <TargetFramework>net9.0</TargetFramework>
         <AssemblyName>LinkDotNet.Blog.Infrastructure</AssemblyName>
         <RootNamespace>LinkDotNet.Blog.Infrastructure</RootNamespace>
+			  <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>

src/LinkDotNet.Blog.Infrastructure/Persistence/CachedRepository.cs

@@ -22,25 +22,24 @@ public CachedRepository(IRepository<T> repository, IMemoryCache memoryCache)
 
     public ValueTask<HealthCheckResult> PerformHealthCheckAsync() => repository.PerformHealthCheckAsync();
 
-    public async ValueTask<T> GetByIdAsync(string id) =>
-        await memoryCache.GetOrCreateAsync(id, async entry =>
+    public async ValueTask<T?> GetByIdAsync(string id) =>
+        (await memoryCache.GetOrCreateAsync(id, async entry =>
         {
             entry.SlidingExpiration = TimeSpan.FromDays(7);
             return await repository.GetByIdAsync(id);
-        });
+        }))!;
 
-    public async ValueTask<IPagedList<T>> GetAllAsync(
-        Expression<Func<T, bool>> filter = null,
-        Expression<Func<T, object>> orderBy = null,
+    public async ValueTask<IPagedList<T>> GetAllAsync(Expression<Func<T, bool>>? filter = null,
+        Expression<Func<T, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue) =>
         await repository.GetAllAsync(filter, orderBy, descending, page, pageSize);
 
     public async ValueTask<IPagedList<TProjection>> GetAllByProjectionAsync<TProjection>(
-        Expression<Func<T, TProjection>> selector,
-        Expression<Func<T, bool>> filter = null,
-        Expression<Func<T, object>> orderBy = null,
+        Expression<Func<T, TProjection>>? selector,
+        Expression<Func<T, bool>>? filter = null,
+        Expression<Func<T, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue) =>

src/LinkDotNet.Blog.Infrastructure/Persistence/IRepository.cs

@@ -12,20 +12,19 @@ public interface IRepository<TEntity>
 {
     ValueTask<HealthCheckResult> PerformHealthCheckAsync();
 
-    ValueTask<TEntity> GetByIdAsync(string id);
+    ValueTask<TEntity?> GetByIdAsync(string id);
 
     ValueTask<IPagedList<TEntity>> GetAllAsync(
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity,
-            object>> orderBy = null,
+        Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue);
 
     ValueTask<IPagedList<TProjection>> GetAllByProjectionAsync<TProjection>(
-        Expression<Func<TEntity, TProjection>> selector,
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity, object>> orderBy = null,
+        Expression<Func<TEntity, TProjection>>? selector,
+        Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue);

src/LinkDotNet.Blog.Infrastructure/Persistence/InMemory/Repository.cs

@@ -15,24 +15,23 @@ public sealed class Repository<TEntity> : IRepository<TEntity>
 
     public ValueTask<HealthCheckResult> PerformHealthCheckAsync() => ValueTask.FromResult(HealthCheckResult.Healthy());
 
-    public ValueTask<TEntity> GetByIdAsync(string id)
+    public ValueTask<TEntity?> GetByIdAsync(string id)
     {
-        var entity = entities.SingleOrDefault(b => b.Id == id);
-        return new ValueTask<TEntity>(entity);
+        var entity = entities.Find(b => b.Id == id);
+        return new ValueTask<TEntity?>(entity);
     }
 
-    public ValueTask<IPagedList<TEntity>> GetAllAsync(
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity, object>> orderBy = null,
+    public ValueTask<IPagedList<TEntity>> GetAllAsync(Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue) =>
         GetAllByProjectionAsync(s => s, filter, orderBy, descending, page, pageSize);
 
     public ValueTask<IPagedList<TProjection>> GetAllByProjectionAsync<TProjection>(
-        Expression<Func<TEntity, TProjection>> selector,
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity, object>> orderBy = null,
+        Expression<Func<TEntity, TProjection>>? selector,
+        Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue)

src/LinkDotNet.Blog.Infrastructure/Persistence/MongoDB/Repository.cs

@@ -36,25 +36,24 @@ public async ValueTask<HealthCheckResult> PerformHealthCheckAsync()
         }
     }
 
-    public async ValueTask<TEntity> GetByIdAsync(string id)
+    public async ValueTask<TEntity?> GetByIdAsync(string id)
     {
         var filter = Builders<TEntity>.Filter.Eq(e => e.Id, id);
         var result = await Collection.FindAsync(filter);
         return await result.FirstOrDefaultAsync();
     }
 
-    public async ValueTask<IPagedList<TEntity>> GetAllAsync(
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity, object>> orderBy = null,
+    public async ValueTask<IPagedList<TEntity>> GetAllAsync(Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue) =>
         await GetAllByProjectionAsync(s => s, filter, orderBy, descending, page, pageSize);
 
     public async ValueTask<IPagedList<TProjection>> GetAllByProjectionAsync<TProjection>(
-        Expression<Func<TEntity, TProjection>> selector,
-        Expression<Func<TEntity, bool>> filter = null,
-        Expression<Func<TEntity, object>> orderBy = null,
+        Expression<Func<TEntity, TProjection>>? selector,
+        Expression<Func<TEntity, bool>>? filter = null,
+        Expression<Func<TEntity, object>>? orderBy = null,
         bool descending = true,
         int page = 1,
         int pageSize = int.MaxValue)