MonadicSharp.Azure.Core

MonadicSharp.Azure.Core is required by all other MonadicSharp.Azure packages. It provides the AzureError hierarchy, HTTP status mapping, RFC 9457 ProblemDetails integration, and IActionResult extensions.

Install

dotnet add package MonadicSharp.Azure.Core

AzureError hierarchy

AzureError extends the base MonadicSharp Error type with Azure-specific properties and HTTP status codes baked in.

// Every AzureError carries an HTTP status code
public abstract record AzureError(string Code, string Message) : Error(Code, Message)
{
    public abstract int HttpStatusCode { get; }
}

// Concrete types
public record NotFoundError(string ResourceType, string ResourceId)
    : AzureError($"{ResourceType}.NotFound", $"{ResourceType} '{ResourceId}' was not found.")
{
    public override int HttpStatusCode => 404;
}

public record RateLimitError(TimeSpan RetryAfter)
    : AzureError("Azure.RateLimit", "Too many requests.")
{
    public override int HttpStatusCode => 429;
}

You never instantiate these directly — they are produced by the extension methods on Azure SDK clients.

HTTP status mapping

AzureError implements IHttpStatusProvider, which ResultExtensions.ToActionResult() uses to determine the correct HTTP response code.

public static class ResultExtensions
{
    // Synchronous
    public static IActionResult ToActionResult<T>(this Result<T> result);

    // Asynchronous — use in controllers and Functions
    public static Task<IActionResult> ToActionResultAsync<T>(this Task<Result<T>> resultTask);
}

Mapping table (default, overridable):

AzureError type	HTTP status
AzureError.NotFound	404
AzureError.Conflict	409
AzureError.ConcurrencyConflict	412
AzureError.Unauthorized	401
AzureError.Forbidden	403
AzureError.RateLimit	429
AzureError.Timeout	408
AzureError.ServiceUnavailable	503
AzureError.Unexpected	500
Error.Validation	422

ProblemDetails integration

ToActionResult serialises failures as RFC 9457 ProblemDetails automatically:

{
  "type": "https://errors.monadic.dev/azure/not-found",
  "title": "Resource not found",
  "status": 404,
  "detail": "Order '3fa85f64-5717-4562-b3fc-2c963f66afa6' was not found.",
  "instance": "/orders/3fa85f64-5717-4562-b3fc-2c963f66afa6"
}

For validation errors, extensions.errors contains field-level details:

{
  "type": "https://errors.monadic.dev/validation",
  "title": "One or more validation errors occurred.",
  "status": 422,
  "extensions": {
    "errors": {
      "UserId": ["UserId is required."],
      "Items": ["Order must contain at least one item."]
    }
  }
}

Minimal API example

using MonadicSharp.Azure.Core;

var app = builder.Build();

app.MapGet("/orders/{id}", async (
    Guid id,
    IOrderService orderService,
    CancellationToken ct) =>
{
    return await orderService.GetOrderAsync(id, ct)
        .ToActionResultAsync();
    // Result<Order> → 200 OK with order body, or ProblemDetails on failure
});

app.MapPost("/orders", async (
    CreateOrderRequest req,
    IOrderService orderService,
    CancellationToken ct) =>
{
    return await orderService.CreateOrderAsync(req, ct)
        .ToActionResultAsync();
    // Result<Order> → 201 Created or 422/409/500 ProblemDetails
});

Custom ProblemDetails factory

Override the default factory to add correlation IDs, custom extensions, or company-specific type URIs:

builder.Services.AddSingleton<IProblemDetailsFactory, MyProblemDetailsFactory>();

public class MyProblemDetailsFactory : IProblemDetailsFactory
{
    public ProblemDetails Create(Error error, HttpContext? context = null)
    {
        var pd = DefaultProblemDetailsFactory.Instance.Create(error, context);
        pd.Extensions["correlationId"] = Activity.Current?.Id ?? context?.TraceIdentifier;
        pd.Extensions["environment"]   = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
        return pd;
    }
}

Registration

builder.Services.AddMonadicAzureCore();
// Registers IProblemDetailsFactory, ResultExtensions, AzureError mappings

Most packages call this internally — you only need it explicitly if using Core without any sub-package.