Attributes reference

Immediate.Apis defines its attributes in the Immediate.Apis.Shared namespace. It also recognises a handful of attributes from ASP.NET Core and from Immediate.Handlers.

MapMethodAttribute

The base type of all the verb attributes, and usable directly for verbs that have no dedicated attribute.

public class MapMethodAttribute : Attribute
{
	public MapMethodAttribute(string method, [StringSyntax("Route")] params string[] routes);

	public string[] Routes { get; }
	public string Method { get; }
	public string[]? Tags { get; init; }
}

• method — the HTTP verb, emitted verbatim into MapMethods(app, route, ["HEAD"], …).
• routes — one or more route templates. One endpoint registration is generated per route.
• Tags — optional registration tags; see Tagged registration.

[Handler]
[MapMethod("HEAD", "/api/health", "/health", Tags = ["Public"])]
public static partial class HeadHealth
{
	// ...
}

The verb attributes

MapGetAttribute, MapPostAttribute, MapPutAttribute, MapPatchAttribute and MapDeleteAttribute are sealed subclasses of MapMethodAttribute that supply the verb for you:

public sealed class MapGetAttribute(
	[StringSyntax("Route")] params string[] routes
) : MapMethodAttribute("GET", routes)
{
	public MapGetAttribute(string route) : this([route]) { }
}

They inherit Routes, Method and Tags. Each also has a single-string constructor, so [MapGet("/users")] works on language versions without collection expressions.

[MapGet("/users")]
[MapGet("/api/users", "/v1/users")]
[MapGet("/users", Tags = ["Public", "Admin"])]

[AttributeUsage(AttributeTargets.Class)] — endpoints are declared on the handler class, never on the Handle method. The generator reads the first Map attribute it finds, so only one per class is meaningful.

RouteGroupAttribute

[AttributeUsage(AttributeTargets.Class)]
public sealed class RouteGroupAttribute([StringSyntax("route")] string route) : Attribute
{
	public string Route { get; }
	public string[]? Tags { get; init; }
}

• route — a single route prefix. Unlike the Map attributes, this is not a params array.
• Tags — filters the entire group, including its endpoints and child groups.

The class must be partial; the generator adds a MapGroup method to it. A [RouteGroup] class nested inside another [RouteGroup] class becomes a child group. See Route groups.

MapGroupAttribute<T>

[AttributeUsage(AttributeTargets.Class)]
public sealed class MapGroupAttribute<T> : Attribute;

Attaches the endpoint to route group T. T must carry [RouteGroup] or IAPI0013 is reported and no endpoint is generated. Name the innermost group when groups are nested:

[Handler]
[MapGet("")]
[MapGroup<Api.V1.Users>]
public static partial class GetUsers
{
	// ...
}

An endpoint carrying [MapGroup<T>] is not registered by MapXxxEndpoints() directly — only through its group.

Recognised ASP.NET Core attributes

[Authorize] and [AllowAnonymous]

From Microsoft.AspNetCore.Authorization, applied to the handler class.

Any other named argument, such as Roles or AuthenticationSchemes, is IAPI0002. If both attributes are present, [AllowAnonymous] wins and IAPI0003 warns. See Authorization.

Binding attributes

[AsParameters] (from Microsoft.AspNetCore.Http) and [FromBody], [FromForm], [FromHeader], [FromQuery] and [FromRoute] (from Microsoft.AspNetCore.Mvc) are read in two positions:

• On the request parameter of Handle/HandleAsync, where they override the inference entirely.
• On a property of the request type, where any of the [FromXxx] five causes the request to bind as [AsParameters].

[FromServices] and [FromKeyedServices] are not part of this set — handler dependencies are resolved by Immediate.Handlers, not by the endpoint. See Binding request data.

Metadata attributes on the handle method

Any attribute on Handle/HandleAsync — [ProducesResponseType<T>], [Produces], [Tags], [EndpointSummary], your own — is copied verbatim onto the generated minimal-API delegate, constructor and named arguments included. See Customizing endpoints.

Recognised methods

These are not attributes, but the generator looks for them by name and shape on your class:

A method with the right name and the wrong shape is ignored and reported: IAPI0004, IAPI0005 and IAPI0011 respectively.