.Net 9 RC1 - Cannot set reponse headers when returning IAsyncEnumerable in controller #57895
Description
Is there an existing issue for this?
- I have searched the existing issues
Describe the bug
Had similar issues on .NET 6 release, adding just in case it's related:
- .Net 6 Preview 7 - Cannot set reponse headers before returning IAsyncEnumerable in controller #35364
- .Net 6 RC1 - Cannot set reponse headers in ExceptionMiddleware returning IAsyncEnumerable in controller #36977 (Was fixed after this one)
In .Net 9 RC1 when trying to set a header before yielding the first value on an IAsyncEnumerable, I get the following error:
System.InvalidOperationException: Headers are read-only, response has already started.
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.ThrowHeadersReadOnlyException()
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.System.Collections.Generic.IDictionary<System.String,Microsoft.Extensions.Primitives.StringValues>.Add(String key, StringValues value)
Implementation of Controller looks like this:
[HttpGet("set-header-aysnc-enumerable-error")]
public async IAsyncEnumerable<WeatherForecastData> GetLocal([EnumeratorCancellation] CancellationToken cancellationToken)
{
var results = await dataService.GetData();
// Adding a response header before yielding first result errors out
Response.Headers.Add("Test", results.Name);
await foreach (var result in results.Data.WithCancellation(cancellationToken))
{
yield return result;
}
}Expected Behavior
The header to be set without errors as is possible in .NET 8
Usecase
We use this mostly to set Pagination headers for paginated lists
Steps To Reproduce
Use this webapi minimal reproduction
https://github.com/gabynevada/.net6-iasync-enumerable-set-header-error
Call endpoint returning IAsyncEnumerable
GET http://localhost:5000/api/data/set-header-aysnc-enumerable-errorCan replicate both on RC1 and the daily build for RC2
Exceptions (if any)
Connection id "0HN6MDAM4CBVH", Request id "0HN6MDAM4CBVH:00000001": An unhandled exception was thrown by the application.
System.InvalidOperationException: Headers are read-only, response has already started.
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.ThrowHeadersReadOnlyException()
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.System.Collections.Generic.IDictionary<System.String,Microsoft.Extensions.Primitives.StringValues>.Add(String key, StringValues value)
at SetResponseHeaders.Controllers.WeatherForecastController.GetLocal(CancellationToken cancellationToken)+MoveNext() in /Users/elvisnievesmiranda/RiderProjects/.net6-iasync-enumerable-set-header-error/Controllers/WeatherForecastController.cs:line 18
at SetResponseHeaders.Controllers.WeatherForecastController.GetLocal(CancellationToken cancellationToken)+System.Threading.Tasks.Sources.IValueTaskSource<System.Boolean>.GetResult()
at System.Text.Json.Serialization.Converters.IAsyncEnumerableOfTConverter`2.OnWriteResume(Utf8JsonWriter writer, TAsyncEnumerable value, JsonSerializerOptions options, WriteStack& state)
at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryWrite(Utf8JsonWriter writer, TCollection value, JsonSerializerOptions options, WriteStack& state)
at System.Text.Json.Serialization.JsonConverter`1.TryWrite(Utf8JsonWriter writer, T& value, JsonSerializerOptions options, WriteStack& state)
at System.Text.Json.Serialization.JsonConverter`1.WriteCore(Utf8JsonWriter writer, T& value, JsonSerializerOptions options, WriteStack& state)
at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(PipeWriter pipeWriter, T rootValue, Int32 flushThreshold, CancellationToken cancellationToken, Object rootValueBoxed)
at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(PipeWriter pipeWriter, T rootValue, Int32 flushThreshold, CancellationToken cancellationToken, Object rootValueBoxed)
at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(PipeWriter pipeWriter, T rootValue, Int32 flushThreshold, CancellationToken cancellationToken, Object rootValueBoxed)
at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(PipeWriter pipeWriter, T rootValue, Int32 flushThreshold, CancellationToken cancellationToken, Object rootValueBoxed)
at Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonOutputFormatter.WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultAsync>g__Logged|22_0(ResourceInvoker invoker, IActionResult result)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
.NET Version
9.0.100-rc.2.24466.1
Anything else?
IDE: JetBrains Rider 2024.2.4 on Mac M1 Arm 64
dotnet --info:
dotnet --info
.NET SDK:
Version: 9.0.100-rc.2.24466.1
Commit: c4104e5646
Workload version: 9.0.100-manifests.792c81b2
MSBuild version: 17.12.0-preview-24463-04+8500d97af
Runtime Environment:
OS Name: Mac OS X
OS Version: 14.6
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.100-rc.2.24466.1/
.NET workloads installed:
Configured to use loose manifests when installing new manifests.
There are no installed workloads to display.
Host:
Version: 9.0.0-rc.2.24462.10
Architecture: arm64
Commit: static