Codify.GrpcCodeFirstDataAnnotations 1.0.0

GRPC Code-First Data Annotations

Data annotation validation for gRPC Code-First models in ASP.NET Core. Automatically validates request messages using System.ComponentModel.DataAnnotations attributes and required properties then returns structured validation errors via gRPC trailers.

Packages

Getting Started

Server Setup

1. Install the NuGet package:

dotnet add package Codify.GrpcCodeFirstDataAnnotations

2. Register services and enable the validation interceptor:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddGrpcDataAnnotationValidation();
builder.Services.AddCodeFirstGrpc(options =>
{
    options.EnableDataAnnotationValidation();
});

3. Add DataAnnotations attributes to your request models:

[DataContract]
public class CreatePersonRequest
{
    [DataMember(Order = 1)]
    [Required]
    [StringLength(50)]
    public string FirstName { get; set; }

    [DataMember(Order = 2)]
    [Required]
    [EmailAddress]
    public string Email { get; set; }

    [DataMember(Order = 3)]
    [Range(1, 120)]
    public int Age { get; set; }

    [DataMember(Order = 4)]
    [Range(typeof(TimeSpan), "00:30:00", "08:00:00")]
    public TimeSpan SessionDuration { get; set; }

    [DataMember(Order = 5)]    
    public required string Job { get; set; }
}

When a request fails validation, the interceptor throws an RpcException with StatusCode.InvalidArgument and includes the validation errors as Base64-encoded JSON in the gRPC trailers.

Client Setup

1. Install the client package:

dotnet add package Codify.GrpcCodeFirstDataAnnotations.Exceptions

2. Catch and read validation errors:

try
{
    var response = await client.CreatePersonAsync(request);
}
catch (RpcException ex)
{
    var errors = ex.GetValidationErrors();
    foreach (var error in errors)
    {
        Console.WriteLine($"{string.Join(", ", error.PropertyNames)}: {error.ErrorMessage}");
    }
}

Custom Validation Handling

Implement IDataAnnotationsResultHandler to customize how validation failures are processed:

public class MyCustomHandler : IDataAnnotationsResultHandler
{
    public Task<DataAnnotationValidationResult> HandleAsync(IList<ValidationResult> failures)
    {
        // Custom logic here
    }
}

Register it before calling AddGrpcDataAnnotationValidation:

builder.Services.AddSingleton<IDataAnnotationsResultHandler, MyCustomHandler>();

Supported gRPC Method Types

• Unary
• Server streaming
• Client streaming
• Duplex streaming

For streaming methods, each incoming message is validated as it is read.

License

See license.txt for details.