PostSharp custom architecture constraint ("HmacSignatureRequiredAttribute.cs" here) requires that every specified method of WebAPIcontroller ("SomeController.cs" here) contains both User Identity and HMAC (keyed-hash message authentication code ) signature. Otherwise compile-time error will happens

HmacSignatureRequiredAttribute.cs

namespace CodeSmells.FakeWebApplication.Aspect
{
    [Serializable]
    [MulticastAttributeUsage(MulticastTargets.Class)]
    public class HmacSignatureRequiredAttribute : ScalarConstraint
    {
        private readonly string[] _httpVerbs;

        public HmacSignatureRequiredAttribute(string[] httpVerbs)
        {
            _httpVerbs = httpVerbs;
        }

        public override void ValidateCode(object target)
        {
            var targetType = (Type)target;

            var httpVerbsMethods = targetType
                .GetMethods(BindingFlags.Public | BindingFlags.Instance)
                .Where(methodInfo => _httpVerbs.Contains(methodInfo.Name))
                .Where(
                    methodInfo =>
                    !(methodInfo.GetParameters().First().ParameterType == typeof (int)
                      && methodInfo.GetParameters().First().Name == "userId")
                    ||
                    !(methodInfo.GetParameters().Last().ParameterType == typeof (string)
                      && methodInfo.GetParameters().Last().Name == "hmacSignature"));

            foreach (var methodInfo in httpVerbsMethods)
            {
                Message.Write(MessageLocation.Of(targetType),
                                SeverityType.Error,
                                "997",
                                "Method '{0}' in ApiController class {1} required to have both userId/hmacSignature",
                                    methodInfo.Name, targetType.FullName);
            }
        }
    }
}

SomeController.cs

namespace CodeSmells.FakeWebApplication.Controllers
{
    // Require following HTTP verbs to have identity and signature
    [HmacSignatureRequired(new[] { "Post", "Put", "Delete" })]
    public class SomeController : ApiController
    {
        public IEnumerable<string> Get()
        {
            return new string[] { "value1", "value2" };
        }
        
        public string Get(int id)
        {
            return "value";
        }
        
        // ok
        public void Post([FromBody]int userId, [FromBody]string value, [FromBody]string hmacSignature)
        {
        }
        
        // ok
        public void Put([FromBody]int userId, int id, [FromBody]string value, [FromBody]string hmacSignature)
        {
        }

        // without both `int userId` and `string hmacSignature` parameters 
        // PostSharp will generate compile-time error message
        public void Delete(int userId, int id, decimal hmacSignature)
        {
        }
    }
}