ASP.NET Core API Reference
This reference documents the D20Tek.Functional.AspNetCore package. It builds on the core Result<T> and Error types to remove repetitive boilerplate when translating results into HTTP responses, supporting both Minimal APIs and MVC/Web API controllers. The descriptions are derived from the XML documentation comments in the source.
The package organizes its members into three areas:
D20Tek.Functional.AspNetCore- error-to-status-code mapping.D20Tek.Functional.AspNetCore.MinimalApi- Minimal API (IResult) integration.D20Tek.Functional.AspNetCore.WebApi- MVC/Web API (ActionResult<T>) integration.
Table of contents
Error type mapping
IErrorTypeMapper
Maps ErrorType integer values to System.Net.HttpStatusCode values. Used by the ASP.NET Core integration to convert domain errors into appropriate HTTP responses. Access the singleton instance via ErrorTypeMapper.Instance.
| Member | Description |
|---|---|
IErrorTypeMapper Configure(Action<IErrorTypeConfigurator>? configure = null) |
Reconfigures the mapper using the provided configurator action. Passing null resets to default mappings. |
bool Contains(int errorType) |
Returns whether a mapping exists for the specified error type. |
HttpStatusCode Convert(int errorType) |
Converts an error type to its mapped HTTP status code. Returns HttpStatusCode.InternalServerError if no mapping exists. |
IErrorTypeMapper For(int errorType, HttpStatusCode statusCode) |
Adds or overrides a mapping from an error type to an HTTP status code. |
IErrorTypeMapper Remove(int errorType) |
Removes the mapping for the specified error type. |
IErrorTypeConfigurator
Fluent interface for configuring the mapping between ErrorType integer values and HttpStatusCode responses. Used within IErrorTypeMapper.Configure.
| Member | Description |
|---|---|
IErrorTypeConfigurator Clear() |
Removes all existing error-type-to-status-code mappings. |
IErrorTypeConfigurator For(int errorType, HttpStatusCode statusCode) |
Maps (or overrides) an error type to a specific HTTP status code. |
IErrorTypeConfigurator Remove(int errorType) |
Removes the mapping for the specified error type. |
ErrorTypeMapper
Singleton implementation of IErrorTypeMapper that maintains a global mapping between ErrorType integer values and HTTP status codes. Access the instance via Instance and reconfigure with Configure.
| Member | Description |
|---|---|
static IErrorTypeMapper Instance |
Gets the singleton IErrorTypeMapper instance with default mappings applied. |
IErrorTypeMapper For(int errorType, HttpStatusCode statusCode) |
Adds or overrides a mapping (see IErrorTypeMapper). |
IErrorTypeMapper Remove(int errorType) |
Removes a mapping. |
bool Contains(int errorType) |
Returns whether a mapping exists. |
HttpStatusCode Convert(int errorType) |
Converts an error type to its mapped HTTP status code. |
IErrorTypeMapper Configure(Action<IErrorTypeConfigurator>? configure = null) |
Reconfigures the mapper. |
Minimal API integration
ResultExtensions (MinimalApi)
Extension methods for converting Result<T> into Minimal API IResult responses. Supports OK, Created, and CreatedAtRoute response patterns.
| Member | Description |
|---|---|
IResult ToApiResult<TValue>(this Result<TValue> result) |
Converts to IResult: 200 OK on success, or Problem Details on failure. |
IResult ToApiResult<TValue, TResponse>(this Result<TValue> result, Func<TValue, TResponse> responseMap) |
Converts to IResult, mapping the success value to a response DTO. |
IResult ToApiResult<TValue, TResponse>(this Result<TValue> result, TResponse response) |
Converts to IResult, returning a fixed response object on success. |
IResult ToCreatedApiResult<TValue>(this Result<TValue> result, string? routeName = null, object? routeValues = null) |
Converts to a 201 CreatedAtRoute response on success, or Problem Details on failure. |
IResult ToCreatedApiResult<TValue, TResponse>(this Result<TValue> result, Func<TValue, TResponse> responseMap, ...) |
Converts to a 201 CreatedAtRoute response, mapping the success value to a response DTO. |
IResult ToCreatedApiResult<TValue, TResponse>(this Result<TValue> result, TResponse response, ...) |
Converts to a 201 CreatedAtRoute response with a fixed response object. |
ResultAsyncExtensions (MinimalApi)
Async counterparts that operate on Task<Result<TValue>>, so results produced by async handlers can be converted without an intermediate await.
| Member | Description |
|---|---|
Task<IResult> ToApiResultAsync<TValue>(this Task<Result<TValue>> result) |
Awaits the result and converts it to an OK/Problem IResult. |
Task<IResult> ToApiResultAsync<TValue, TResponse>(...) |
Awaits and converts, mapping the success value to a response DTO or fixed response. |
Task<IResult> ToCreatedApiResultAsync<TValue>(...) |
Awaits and converts to a 201 CreatedAtRoute response. |
Task<IResult> ToCreatedApiResultAsync<TValue, TResponse>(...) |
Awaits and converts to a 201 CreatedAtRoute response with a mapped or fixed response. |
TypedResultExtensions
Extension methods on IResultExtensions for converting Error arrays into RFC 7807 Problem Details responses in Minimal APIs.
| Member | Description |
|---|---|
IResult Problem(this IResultExtensions _, IEnumerable<Error> errors) |
Converts a collection of errors into a Problem Details response. Validation-only errors produce a 400 ValidationProblem; other errors produce a standard Problem response. |
IResult Problem(this IResultExtensions _, Error error) |
Converts a single error into a Problem Details response. |
IResult Problem(this IResultExtensions _, int statusCode, string errorCode, string message) |
Creates a Problem Details response with an explicit status code, error code, and message. |
Invoke these via Results.Extensions.Problem(...).
HandleResultFilter
An endpoint filter for Minimal APIs that automatically converts IResultMonad return values into appropriate HTTP responses (200 OK or Problem Details). Register with .AddEndpointFilter<HandleResultFilter>() on route handlers.
| Member | Description |
|---|---|
ValueTask<object?> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next) |
Invokes the next filter and, if the result is an IResultMonad, converts it to an IResult. |
HandleTypedResultFilter<T>
A typed endpoint filter for Minimal APIs that converts Result<T> return values into appropriate HTTP responses. Use when the endpoint's return type is known at compile time. Register with .AddEndpointFilter<HandleTypedResultFilter<T>>(). T must be a reference type.
| Member | Description |
|---|---|
ValueTask<object?> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next) |
Invokes the next filter and, if the result is a Result<T>, converts it to a 200 OK or Problem Details response. |
Web API integration
ResultExtensions (WebApi)
Extension methods for converting Result<T> into ActionResult<T> responses in Web API controllers. Supports OK, Created, and CreatedAtAction patterns.
| Member | Description |
|---|---|
ActionResult<TResponse> ToActionResult<TValue, TResponse>(this Result<TValue> result, Func<TValue, TResponse> responseMap, ControllerBase controller) |
Converts to an ActionResult<T>, mapping the success value to a response DTO. |
ActionResult<TResponse> ToActionResult<TValue, TResponse>(this Result<TValue> result, TResponse response, ControllerBase controller) |
Converts to an ActionResult<T>, returning a fixed response on success. |
ActionResult<TResponse> ToCreatedActionResult<TValue, TResponse>(this Result<TValue> result, Func<TValue, TResponse> responseMap, ControllerBase controller, string? routeName = null, object? routeValues = null) |
Converts to a 201 CreatedAtAction response, mapping the success value. |
ActionResult<TResponse> ToCreatedActionResult<TValue, TResponse>(this Result<TValue> result, TResponse response, ControllerBase controller, ...) |
Converts to a 201 CreatedAtAction response with a fixed response object. |
ResultAsyncExtensions (WebApi)
Async counterparts that operate on Task<Result<TValue>>.
| Member | Description |
|---|---|
Task<ActionResult<TResponse>> ToActionResultAsync<TValue, TResponse>(...) |
Awaits the result and converts it to an ActionResult<T>, with a mapped or fixed response. |
Task<ActionResult<TResponse>> ToCreatedActionResultAsync<TValue, TResponse>(...) |
Awaits the result and converts it to a 201 CreatedAtAction response, with a mapped or fixed response. |
ActionResultExtensions
Extension methods for ControllerBase that convert Error arrays into RFC 7807 Problem Details ActionResult<T> responses for Web API controllers.
| Member | Description |
|---|---|
ActionResult<TResult> Problem<TResult>(this ControllerBase controller, IEnumerable<Error> errors) |
Converts a collection of errors into a Problem Details ActionResult<T>. Validation-only errors produce a 400 ValidationProblem; other errors produce a standard Problem response. |
ActionResult<TResult> Problem<TResult>(this ControllerBase controller, Error error) |
Converts a single error into a Problem Details ActionResult<T>. |
ActionResult<TResult> Problem<TResult>(this ControllerBase controller, int statusCode, string errorCode, string message) |
Creates a Problem Details response with an explicit status code, error code, and message. |
IActionResult ToIActionResult(this IConvertToActionResult actionResult) |
Converts an IConvertToActionResult to an IActionResult. |
Task<IActionResult> ToIActionResult(this Task<ActionResult<T>> ...) |
Asynchronously converts a Task<ActionResult<T>> to an IActionResult. |
HandleResultFilter
An MVC action filter that automatically converts IResultMonad return values from controller actions into appropriate ActionResult responses (OK or Problem Details). Register globally or per-controller with [ServiceFilter(typeof(HandleResultFilter))].
| Member | Description |
|---|---|
void OnActionExecuting(ActionExecutingContext context) |
No-op; part of the IActionFilter contract. |
void OnActionExecuted(ActionExecutedContext context) |
Converts an IResultMonad returned in an ObjectResult into an ActionResult response. |
static Optional<IResultMonad> GetResultMonad(ObjectResult objRes) |
Extracts an IResultMonad from the given ObjectResult, if present. |