AnnotatedResult 1.0.0-preview.13

AnnotatedResult

AnnotatedResult is a lightweight .NET model validation library utilizing System.ComponentModel.DataAnnotations.

NuGet Package

dotnet add package AnnotatedResult --version 1.0.0-preview.12

Overview

Validation

public class Request
{
    [Required]
    [RegularExpression(RegexPattern.Username)]
    public string Username { get; init; }

    [EmailAddress]
    public string Email { get; init; }

    [Required]
    [RegularExpression(RegexPattern.StrongPassword)]
    public string Password { get; init; }
}

Request is a class with Data Annotation attribute assigned for each properties. AnnotatedResult make it so it's easy to validate.

    var request = new Request();
    bool isValid = request.TryValidate(out Error[] errors);

TryValidate is an extension method use to validation any instance of object. If the object has Data Annotation attribute assigned to either field of property it will perform the validation process and return a boolean and an out parameter of type Error[].

    if(!isValid)
    {
        Result<Request> result = Result<Request>.Invalid(errors);
        return result;
    }

    Result<Request> result = Result<Request>.Ok(request);
    return result;

Result<T> is a generic wrapper class that encapsulate Data Annotation validation result. The example above it hold the generic type of Request. Result<T> can be modified whether the is a success or an error--or a specified error such as Unauthorized or NotFound.

Result<T> with 200 status code or Ok status return the validated object in question where as error (specified or otherwise) return list of errors.

    var ok           = Result<Request>.Ok(request);

    var error        = Result<Request>.Error(errors);
    var invalid      = Result<Request>.Invalid(errors);
    var unauthorized = Result<Request>.Unauthorized(errors);
    var forbidden    = Result<Request>.Forbidden(errors);
    var conflict     = Result<Request>.Conflict(errors);
    var notFound     = Result<Request>.NotFound(errors);

Usage

The library provides a convenient way to handle the validation results using the Result<T> class. Here are some common patterns:

Match Success and Failure

    result.Match(
        () => Console.WriteLine("Operation successful!"),
        (statusAndErrors) => Console.WriteLine($"Operation failed with status {statusAndErrors.status}. Errors: {statusAndErrors.errors.Count}")
    );

Match Success and Return Value

    string resultValue = result.Match(
        (value) => value,
        (statusAndErrors) => "Default Value"
    );

Add Metadata

    result.AddMetadata(new Dictionary<string, object>
    {
        { "Key1", "Value1" },
        { "Key2", 42 }
    });

Inherit Result

    Result<DerivedType> derivedResult = Result<DerivedType>.Inherit(result);