MinimalApi MapMethods with muti methods use WithOpenApi() throw Error!

[vipwan]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

both .net7 & .net8 error

System.Linq.ThrowHelper.ThrowMoreThanOneElementException()
System.Linq.Enumerable.TryGetSingle(IEnumerable source, out bool found)
System.Linq.Enumerable.SingleOrDefault(IEnumerable source)
Microsoft.AspNetCore.OpenApi.OpenApiGenerator.GetOpenApiOperation(MethodInfo methodInfo, EndpointMetadataCollection metadata, RoutePattern pattern)
Microsoft.AspNetCore.Builder.OpenApiEndpointConventionBuilderExtensions.AddAndConfigureOperationForEndpoint(EndpointBuilder endpointBuilder, Func<OpenApiOperation, OpenApiOperation> configure)
Microsoft.AspNetCore.Builder.OpenApiEndpointConventionBuilderExtensions+<>c__DisplayClass1_0.b__0(EndpointBuilder endpointBuilder)
Microsoft.AspNetCore.Routing.RouteEndpointDataSource.CreateRouteEndpointBuilder(RouteEntry entry, RoutePattern groupPrefix, IReadOnlyList<Action> groupConventions, IReadOnlyList<Action> groupFinallyConventions)
Microsoft.AspNetCore.Routing.RouteEndpointDataSource.get_Endpoints()
Microsoft.AspNetCore.Routing.CompositeEndpointDataSource.CreateEndpointsUnsynchronized()
Microsoft.AspNetCore.Routing.CompositeEndpointDataSource.EnsureEndpointsInitialized()
Microsoft.AspNetCore.Routing.DataSourceDependentCache.Initialize()
System.Threading.LazyInitializer.EnsureInitializedCore(ref T target, ref bool initialized, ref object syncLock, Func valueFactory)
Microsoft.AspNetCore.Routing.Matching.DataSourceDependentMatcher..ctor(EndpointDataSource dataSource, Lifetime lifetime, Func matcherBuilderFactory)
Microsoft.AspNetCore.Routing.Matching.DfaMatcherFactory.CreateMatcher(EndpointDataSource dataSource)
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.InitializeCoreAsync()
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.g__AwaitMatcher|8_0(EndpointRoutingMiddleware middleware, HttpContext httpContext, Task matcherTask)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

7.0.11

Anything else?

No response

[captainsafia]

@vipwan Thanks for reporting this issue!

Yes, unfortunately, this is a known limitation of the current design. We only support emitting one OpenApiOperation per endpoint so multiple HTTP methods are not supported since they require multiple OpenApiOperations per endpoint definition.

If it's possible for you, I'd recommend using a combination of route groups and local methods to get the desired behavior.

app.MapMethods("/hello", new[] { "GET", "POST" }, () => Results.Ok()).WithOpenApi();
// becomes
var hello = app.MapGroup("/hello").WithOpenApi();
IResult GetHello() => Results.Ok();
hello.MapGet("", GetHello);
hello.MapPost("", GetHello);

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[vipwan]

@vipwan Thanks for reporting this issue!

是的，不幸的是，这是当前设计的已知限制。我们仅支持为每个端点发出一个 OpenApiOperation，因此不支持多个 HTTP 方法，因为它们需要每个端点定义多个 OpenApiOperations。

如果可能的话，我建议结合使用路由组和本地方法来获得所需的行为。

app.MapMethods("/hello", new[] { "GET", "POST" }, () => Results.Ok()).WithOpenApi();
// becomes
var hello = app.MapGroup("/hello").WithOpenApi();
IResult GetHello() => Results.Ok();
hello.MapGet("", GetHello);
hello.MapPost("", GetHello);

It solves the problem, but this writing is really verbose, and I still hope to add relevant features in the future 😄