ResultObjects

About

ResultObjects provide a simple and easy to use object Result to handle state of applications. This minimizes the use of Exceptions, which is bad for application performance.

ResultObjects belong in the application-layer of the architecture. We do not recommend adding this to neither domains, nor primitives.

Installation

dotnet add package Arcturus.ResultObjects 

Usage

Result objects have a state where Result.IsSuccess is either true/false as well as Result.IsFailure will become the opposite true/false.

Calling .Success() will automatically set Result.IsSuccess to true, and .Failure() will automatically set Result.IsSuccess to false.

To use the library, simply define a result using the API:

// defines a value-less success result
var successResult = Result.Success();

Success

Use the generic API to provide a value of the result. The value is available from the Result.Value property.

// defines a value-based success result
//  successResult would be of type Result<ReturnValue>
var successResult = Result.Success(new ReturnValue() { ... });

Failure

When things go bad, you can use the failure API to provide a failed response. Fail responses do not handle values, as there is not reason to pass along the value of a failed operation.

// defines a value-less failure result
var failedResult = Result.Failure();

// define a value-less failure result of generic type
var failedResult = Result.Failure<ReturnValue>();

Who's at fault?

To help provide context and information, failures can hold a Fault reason.

var failedResult = Result.Failure<ReturnValue>(Fault.From("ReturnValue is missing a correct state."));

Fault objects hold two properties.

property	type	description
Code	string	Optional. A system specific code of the fault.
Message	string	Required. A human friendly message of the fault.

Specialized faults

Specialized faults provide response, by setting an http status code of the resulting Result object. This enables a minimal design when returning fault using the implicit operator.

fault	corresponding status code
AmbiguousFault	Ambiguous
BadRequestFault	BadRequest
ConflictFault	Conflict
ConstraintFault	UnprocessableContent
ForbiddenFault	Forbidden
PaymentFault	Payment
UnauthorizedFault	Unauthorized

Extensions

Result objects have two extensions allowing to provide further state.

WithException

Allows passing on a captured exception.

try {
  // do action that throws an exception
  ...
  return Result.Success();
}
catch (Exception e)
{
  return Result
    .Failure(new Fault("error", e.Message))
    .WithException(new Exception("Error"));
}

WithHttpStatusCode

Allows assigning a Http status code to the result. This is extremely useful when using the ASP.NET Core extension to provide response results.

return Result
  .Failure(Fault.From("error", e.Message))
  .WithHttpStatusCode(System.Net.HttpStatusCode.BadRequest)
  .WithException(new Exception("Error"));