Fluens.Web 0.7.2

Fluens.Web

ASP.NET Core base types for Fluens web libraries: Result-to-HTTP mapping, global exception handler, and paged responses.

Installation

dotnet add package Fluens.Web

Usage

fluensBuilder.AddWeb();

// In middleware pipeline
app.UseExceptionHandler(); // GlobalExceptionHandler returns ProblemDetails

ResultExtensions map Result / Result<T> to HTTP responses:

app.MapPost("/orders", async (CreateOrder cmd, ICommandDispatcher dispatcher, CancellationToken ct) =>
{
    var result = await dispatcher.SendAsync(cmd, ct);
    return result.ToHttpResult(); // 204 on success, 4xx/5xx on failure
});

Error mapping: NotFoundError → 404, ValidationError → 400, ConflictError → 409, ForbiddenError → 403, unknown Error → 500.

Server-Side Localization

Pass an optional IStringLocalizer to translate error messages server-side. The Error.Message is used as the localization key and {Key} placeholders are replaced with MessageArgs values:

app.MapPost("/orders", async (
    CreateOrder cmd,
    ICommandDispatcher dispatcher,
    IStringLocalizer<OrderErrors> localizer,
    CancellationToken ct) =>
{
    var result = await dispatcher.SendAsync(cmd, ct);
    return result.ToHttpResult(localizer); // Translates error messages using localizer
});

When no localizer is provided (default), Error.Message is returned as-is — maintaining full backward compatibility. MessageArgs is always included in ProblemDetails.Extensions["messageArgs"] regardless of whether a localizer is used.

IServiceCatalog

IServiceCatalog is the central, synchronous service-resolution contract consumed by web libraries (HTTP, messaging) without depending on the underlying discovery implementation. It lives in the base project — like IHealthEndpointInfo — so consumers stay decoupled from the Consul-backed implementation in Fluens.Web.Discovery.

public interface IServiceCatalog
{
    // One healthy endpoint for the service, or null when none is available.
    ResolvedServiceEndpoint? Resolve(string serviceName);

    // Services advertising the tag, optionally filtered by metadata key/value pairs.
    IReadOnlyList<DiscoveredService> List(string tag, IReadOnlyDictionary<string, string>? metaMatch = null);

    // Fires when the catalog snapshot changes (topology updates).
    IChangeToken GetChangeToken();
}

The return types are immutable records:

var endpoint = catalog.Resolve("orders-api");
Uri uri = endpoint?.ToUri(); // scheme://host:port/

foreach (var service in catalog.List("fluens-mesh", new Dictionary<string, string> { ["fluens-cluster"] = "c1" }))
{
    ResolvedServiceEndpoint? first = service.FirstHealthyEndpoint; // null when no endpoints
}

• ResolvedServiceEndpoint(string Scheme, string Host, int Port) — ToUri() composes an absolute scheme://host:port/ URI.
• DiscoveredService(string ServiceName, IReadOnlyList<ResolvedServiceEndpoint> Endpoints, IReadOnlyList<string> Tags, IReadOnlyDictionary<string, string> Meta) — FirstHealthyEndpoint returns the first endpoint or null when Endpoints is empty.

TranslatableMessageExtensions

Translate TranslatableMessage instances (from Fluens.Kernel.Translations) using ASP.NET Core IStringLocalizer:

var message = new TranslatableMessage("order.status.changed")
    .WithArg("orderId", "ORD-123")
    .WithArg("newStatus", "Shipped");

// Translate using IStringLocalizer — Code is the localization key,
// {Key} placeholders are replaced with Args values
string translated = message.Translate(localizer);

License

This project is licensed under the MIT License.