Validator for files has breaking changes, but very easy to migrate (just name change)

Author: HaikAsatryan

Readme.md

@@ -473,18 +473,50 @@ handler. If validation fails, a `BadRequestException` is thrown with the validat
 
 ### FluentValidation Extensions
 
-The package includes extension methods to simplify common validation scenarios:
-
-- File Validations:
-    - HasMaxFileSize(maxFileSizeInMb): Validates that an uploaded file does not exceed the specified maximum size.
-    - FileTypeIsOneOf(allowedFileExtensions): Validates that the uploaded file has one of the allowed file
-      extensions.
-- String Validations:
-    - IsValidJson(): Validates that a string is a valid JSON.
-    - IsXssSanitized(): Validates that a string is sanitized against XSS attacks.
-    - IsEmail(): Validates that a string is a valid email address. Native one is not working correctly.
-    - IsPhoneNumber(): Validates that a string is a valid phone number. Format requires area code to be in `()`.
-    - IsEmailOrPhoneNumber(): Validates that a string is either a valid email address or a valid phone number.
+We ship lightweight validators and presets for common scenarios, including file uploads and string checks.
+All file rules use name/extension checks only (simple + fast). Deep validation still happens inside your storage layer.
+
+**File upload validators**
+
+**Single file (`IFormFile`)**
+
+```csharp
+RuleFor(x => x.Avatar)
+   .HasMaxSizeMb(6)                       // size cap in MB
+   .ExtensionIn(".jpg", ".jpeg", ".png"); // or use a preset set below
+
+```
+
+**File collection (`IFormFileCollection`)**
+
+```csharp
+RuleFor(x => x.Docs)
+   .MaxCount(10)                          // number of files
+   .EachHasMaxSizeMb(10)                  // per-file size cap (MB)
+   .EachExtensionIn(CommonFileSets.Documents)
+   .TotalSizeMaxMb(50);                   // sum of all files (MB)
+```
+
+**Presets**
+
+```csharp
+using SharedKernel.ValidatorAndMediatR.Validators.Files;
+
+CommonFileSets.Images               // .jpg, .jpeg, .png, .webp, .heic, .heif, .svg, .avif
+CommonFileSets.Documents            // .pdf, .txt, .csv, .json, .xml, .yaml, .yml, .md, .docx, .xlsx, .pptx, .odt, .ods, .odp
+CommonFileSets.ImagesAndAnimations  // Images + .gif
+CommonFileSets.ImagesAndDocuments   // Images + Documents
+```
+
+**String validators**
+
+```csharp
+RuleFor(x => x.Email).IsEmail();
+RuleFor(x => x.Phone).IsPhoneNumber();
+RuleFor(x => x.Contact).IsEmailOrPhoneNumber(); // alias: IsPhoneNumberOrEmail
+RuleFor(x => x.PayloadJson).IsValidJson();
+RuleFor(x => x.Content).IsXssSanitized();
+```
 
 ## Cors
 

SharedKernel.Demo/VerticalFeature.cs

@@ -0,0 +1,54 @@
+using FluentMinimalApiMapper;
+using FluentValidation;
+using MediatR;
+using Microsoft.AspNetCore.Mvc;
+using SharedKernel.ValidatorAndMediatR.Validators;
+using SharedKernel.ValidatorAndMediatR.Validators.Files;
+using ICommand = SharedKernel.ValidatorAndMediatR.ICommand;
+
+namespace SharedKernel.Demo;
+
+public class VerticalFeature : IEndpoint
+{
+   public void AddRoutes(IEndpointRouteBuilder app)
+   {
+      app.MapPost("vertical",
+            async ([AsParameters] VerticalCommand command, [FromServices] ISender sender) =>
+            {
+               await sender.Send(command);
+               return Results.Ok();
+            })
+         .WithTags("vertical")
+         .DisableAntiforgery();
+   }
+}
+
+public class VerticalCommand : ICommand
+{
+   public IFormFile? Avatar { get; init; }
+   public IFormFileCollection? Docs { get; init; }
+}
+
+public class VerticalCommandHandler : IRequestHandler<VerticalCommand>
+{
+   public Task Handle(VerticalCommand request, CancellationToken cancellationToken)
+   {
+      return Task.CompletedTask;
+   }
+}
+
+public class VerticalCommandValidator : AbstractValidator<VerticalCommand>
+{
+   public VerticalCommandValidator()
+   {
+      RuleFor(x => x.Avatar)
+         .HasMaxSizeMb(3)
+         .ExtensionIn(".jpg", ".png");
+
+      RuleFor(x => x.Docs)
+         .MaxCount(4)
+         .EachHasMaxSizeMb(4)
+         .EachExtensionIn(CommonFileSets.Documents)
+         .TotalSizeMaxMb(10);
+   }
+}

src/SharedKernel/SharedKernel.csproj

@@ -8,13 +8,13 @@
         <PackageReadmeFile>Readme.md</PackageReadmeFile>
         <Authors>Pandatech</Authors>
         <Copyright>MIT</Copyright>
-        <Version>1.7.0</Version>
+        <Version>1.8.0</Version>
         <PackageId>Pandatech.SharedKernel</PackageId>
         <Title>Pandatech Shared Kernel Library</Title>
         <PackageTags>Pandatech, shared kernel, library, OpenAPI, Swagger, utilities, scalar</PackageTags>
         <Description>Pandatech.SharedKernel provides centralized configurations, utilities, and extensions for ASP.NET Core projects. For more information refere to readme.md document.</Description>
         <RepositoryUrl>https://github.com/PandaTechAM/be-lib-sharedkernel</RepositoryUrl>
-        <PackageReleaseNotes>Maintenance mode has been added</PackageReleaseNotes>
+        <PackageReleaseNotes>Validator for files has breaking changes, but very easy to migrate (just name change)</PackageReleaseNotes>
     </PropertyGroup>
 
     <ItemGroup>
@@ -46,14 +46,14 @@
         <PackageReference Include="OpenTelemetry.Instrumentation.EntityFrameworkCore" Version="1.0.0-beta.12"/>
         <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.12.0"/>
         <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" Version="1.12.0"/>
-        <PackageReference Include="Pandatech.Crypto" Version="6.0.0"/>
+        <PackageReference Include="Pandatech.Crypto" Version="6.1.0" />
         <PackageReference Include="Pandatech.DistributedCache" Version="4.0.9"/>
         <PackageReference Include="PandaTech.FileExporter" Version="4.1.2"/>
         <PackageReference Include="PandaTech.FluentImporter" Version="3.0.9"/>
         <PackageReference Include="Pandatech.FluentMinimalApiMapper" Version="2.0.4"/>
         <PackageReference Include="Pandatech.PandaVaultClient" Version="4.0.6"/>
         <PackageReference Include="Pandatech.ResponseCrafter" Version="5.2.2"/>
-        <PackageReference Include="Scalar.AspNetCore" Version="2.8.1"/>
+        <PackageReference Include="Scalar.AspNetCore" Version="2.8.4" />
         <PackageReference Include="Serilog.AspNetCore" Version="9.0.0"/>
         <PackageReference Include="Serilog.Sinks.Async" Version="2.1.0"/>
         <PackageReference Include="Serilog.Sinks.Grafana.Loki" Version="8.3.1"/>

src/SharedKernel/ValidatorAndMediatR/Behaviors/ValidationAggregation.cs

@@ -0,0 +1,65 @@
+using FluentValidation.Results;
+using ResponseCrafter.HttpExceptions;
+
+namespace SharedKernel.ValidatorAndMediatR.Behaviors;
+
+internal static class ValidationAggregation
+{
+   public static (string? Message, Dictionary<string, string>? Errors) ToMessageAndErrors(
+      IEnumerable<ValidationFailure> failures)
+   {
+      var globalMessages = new List<string>();
+      var errors = new Dictionary<string, string>(StringComparer.Ordinal);
+
+      foreach (var f in failures)
+      {
+         var prop = (f.PropertyName ?? string.Empty).Trim();
+
+         // Global messages (no property name) -> headline message
+         if (string.IsNullOrEmpty(prop))
+         {
+            if (!string.IsNullOrWhiteSpace(f.ErrorMessage))
+            {
+               globalMessages.Add(f.ErrorMessage);
+            }
+
+            continue;
+         }
+
+         // Per-property errors: keep the first message per property for brevity
+         if (!errors.ContainsKey(prop))
+         {
+            errors[prop] = f.ErrorMessage;
+         }
+      }
+
+      var message = globalMessages.Count > 0
+         ? string.Join(" | ", globalMessages.Distinct())
+         : null;
+
+      return (message, errors.Count > 0 ? errors : null);
+   }
+
+   public static BadRequestException ToBadRequestException(IEnumerable<ValidationFailure> failures)
+   {
+      var (message, errors) = ToMessageAndErrors(failures);
+
+      if (!string.IsNullOrWhiteSpace(message) && errors is not null)
+      {
+         return new BadRequestException(message, errors);
+      }
+
+      if (!string.IsNullOrWhiteSpace(message))
+      {
+         return new BadRequestException(message);
+      }
+
+      if (errors is not null)
+      {
+         return new BadRequestException(errors);
+      }
+
+      // Should not happen if we had failures, but just in case:
+      return new BadRequestException("validation_failed");
+   }
+}

src/SharedKernel/ValidatorAndMediatR/Behaviors/ValidationBehaviorWithResponse.cs

@@ -18,20 +18,17 @@ public async Task<TResponse> Handle(TRequest request,
       }
 
       var context = new ValidationContext<TRequest>(request);
+      var results = await Task.WhenAll(validators.Select(v => v.ValidateAsync(context, cancellationToken)));
 
-      var validationResults = await Task.WhenAll(validators.Select(v => v.ValidateAsync(context, cancellationToken)));
-      var failures = validationResults.SelectMany(r => r.Errors)
-                                      .Where(f => f != null)
-                                      .ToList();
+      var failures = results.SelectMany(r => r.Errors)
+                            .Where(f => f is not null)
+                            .ToList();
 
       if (failures.Count == 0)
       {
          return await next(cancellationToken);
       }
 
-      var errors = failures.GroupBy(e => e.PropertyName, e => e.ErrorMessage)
-                           .ToDictionary(failureGroup => failureGroup.Key, failureGroup => failureGroup.First());
-
-      throw new BadRequestException(errors);
+      throw ValidationAggregation.ToBadRequestException(failures);
    }
 }

src/SharedKernel/ValidatorAndMediatR/Behaviors/ValidationBehaviorWithoutResponse.cs

@@ -18,20 +18,17 @@ public async Task<TResponse> Handle(TRequest request,
       }
 
       var context = new ValidationContext<TRequest>(request);
+      var results = await Task.WhenAll(validators.Select(v => v.ValidateAsync(context, cancellationToken)));
 
-      var validationResults = await Task.WhenAll(validators.Select(v => v.ValidateAsync(context, cancellationToken)));
-      var failures = validationResults.SelectMany(r => r.Errors)
-                                      .Where(f => f != null)
-                                      .ToList();
+      var failures = results.SelectMany(r => r.Errors)
+                            .Where(f => f is not null)
+                            .ToList();
 
       if (failures.Count == 0)
       {
          return await next(cancellationToken);
       }
 
-      var errors = failures.GroupBy(e => e.PropertyName, e => e.ErrorMessage)
-                           .ToDictionary(failureGroup => failureGroup.Key, failureGroup => failureGroup.First());
-
-      throw new BadRequestException(errors);
+      throw ValidationAggregation.ToBadRequestException(failures);
    }
 }

src/SharedKernel/ValidatorAndMediatR/Validators/FileSizeValidator.cs

@@ -0,0 +1,17 @@
+namespace SharedKernel.ValidatorAndMediatR.Validators.Files;
+
+public static class CommonFileSets
+{
+   public static readonly string[] ImagesAndAnimations =
+      [".jpg", ".jpeg", ".png", ".gif", ".webp", ".heic", ".heif", ".svg", ".avif"];
+
+   public static readonly string[] Documents =
+   [
+      ".pdf", ".txt", ".csv", ".json", ".xml", ".yaml", ".yml", ".md", ".docx", ".xlsx", ".pptx", ".odt", ".ods", ".odp"
+   ];
+
+   public static readonly string[] Images = [".jpg", ".jpeg", ".png", ".webp", ".heic", ".heif", ".svg", ".avif"];
+
+   public static readonly string[] ImagesAndDocuments = Images.Concat(Documents)
+                                                              .ToArray();
+}

src/SharedKernel/ValidatorAndMediatR/Validators/FileTypeValidator.cs

@@ -0,0 +1,16 @@
+namespace SharedKernel.ValidatorAndMediatR.Validators.Files;
+
+internal static class Exts
+{
+   public static string Norm(string ext)
+   {
+      if (string.IsNullOrWhiteSpace(ext))
+      {
+         return "";
+      }
+
+      return ext.StartsWith('.') ? ext.ToLowerInvariant() : "." + ext.ToLowerInvariant();
+   }
+
+   public static string GetExt(string fileName) => Norm(Path.GetExtension(fileName));
+}