FIX Concurrency Problem in MediatR

src/SwiftLink.Application/Common/Interfaces/IApplicationDbContext.cs

@@ -5,18 +5,12 @@
 /// </summary>
 public interface IApplicationDbContext
 {
-    /// <summary>
-    /// Save all entities in to database.
-    /// </summary>
-    /// <returns></returns>
-    public Task<Result> SaveChangesAsync();
-
     /// <summary>
     /// Save all entities in to database.
     /// </summary>
     /// <param name="cancellationToken"></param>
     /// <returns></returns>
-    public Task<Result> SaveChangesAsync(CancellationToken cancellationToken);
+    public Task<int> SaveChangesAsync(CancellationToken cancellationToken);
 
     DbSet<TEntity> Set<TEntity>() where TEntity : class;
 }

src/SwiftLink.Application/ConfigServices.cs

@@ -16,7 +16,7 @@ public static IServiceCollection RegisterApplicationServices(this IServiceCollec
         services.AddMediatR(config =>
         {
             config.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
-            config.AddBehavior(typeof(IPipelineBehavior<,>), typeof(ValidationBehavior<,>));
+           // config.AddBehavior(typeof(IPipelineBehavior<,>), typeof(ValidationBehavior<,>));
         });
 
         services.AddScoped<IShortCodeGenerator, TimeBasedShortCodeGenerator>();

src/SwiftLink.Application/UseCases/Links/GenerateCommand/GenerateShortCodeCommandHandler.cs

@@ -17,7 +17,7 @@ public class GenerateShortCodeCommandHandler(IApplicationDbContext dbContext,
     private readonly IShortCodeGenerator _codeGenerator = codeGenerator;
     private readonly AppSettings _options = options.Value;
 
-    public async Task<Result<object>> Handle(GenerateShortCodeCommand request, CancellationToken cancellationToken)
+    public async Task<Result<object>> Handle(GenerateShortCodeCommand request, CancellationToken cancellationToken = default)
     {
         var link = new Link
         {
@@ -32,7 +32,7 @@ public async Task<Result<object>> Handle(GenerateShortCodeCommand request, Cance
         _dbContext.Set<Link>().Add(link);
 
         var dbResult = await _dbContext.SaveChangesAsync(cancellationToken);
-        if (dbResult.IsFailure)
+        if (dbResult > 1)
             return Result<object>.Failure(Constants.Database.InsertFailed);
 
         await _cache.Set(request.Url, JsonSerializer.Serialize(link), link.ExpirationDate);

src/SwiftLink.Infrastructure/Persistence/Context/ApplicationDbContext.cs

@@ -1,10 +1,12 @@
-using SwiftLink.Domain.Common;
+using Azure;
+using SwiftLink.Domain.Common;
 using SwiftLink.Infrastructure.Persistence.Extensions;
 using System.Reflection;
 
 namespace SwiftLink.Infrastructure.Persistence.Context;
 
-public class ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : DbContext(options), IApplicationDbContext
+public class ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
+    : DbContext(options), IApplicationDbContext
 {
     protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
     {
@@ -22,16 +24,11 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
             relationship.DeleteBehavior = DeleteBehavior.NoAction;
     }
 
-    public async Task<Result> SaveChangesAsync()
-        => await SaveChangesAsync(default);
-
-    public new async Task<Result> SaveChangesAsync(CancellationToken cancellationToken)
+    public new async Task<Result> SaveChangesAsync(CancellationToken cancellationToken = default)
     {
         try
         {
-            return await base.SaveChangesAsync(cancellationToken) is 0 ?
-                            Result.Failure("Faile On Save into Database.") :
-                            Result.Success();
+            return await base.SaveChangesAsync(cancellationToken) is 0 ? Result.Failure("Database operation failed :(") : Result.Success();
         }
         catch (Exception ex)
         {

src/SwiftLink.Presentation/Controllers/LinkController.cs

@@ -10,8 +10,6 @@ public class LinkController : BaseController
 {
     [HttpPost]
     [ShortenEndpointFilter]
-    public JsonResult Shorten([FromBody] GenerateShortCodeCommand command)
-    {
-        return Json(MediatR.Send(command));
-    }
+    public async Task<IActionResult> Shorten([FromBody] GenerateShortCodeCommand command,CancellationToken cancellationToken=default)
+        =>Ok(await MediatR.Send(command, cancellationToken));
 }

src/SwiftLink.Shared/Result.cs

@@ -1,13 +1,11 @@
-using System.Text.Json.Serialization;
-
-namespace SwiftLink.Shared;
+namespace SwiftLink.Shared;
 
 public class Result
 {
     public bool IsSuccess { get; init; }
 
-    [JsonIgnore]
-    public bool IsFailure => !IsSuccess;
+    public bool IsFailure
+        => !IsSuccess;
 
     public string Message { get; init; }