InvalidOperationException: Invalid non-ASCII or control character in header: 0x00F8

[severisv]

When getting files from Azure Blob Storage in my ASP.NET Core application, I obtain a temporary URI with an access signature and then redirect the user to that URI, like this:

type FileController () =
    inherit Controller(container: FileContainer)
 
    member this.GetFile(path: string) =
          let blob = container.GetBlockBlobReference path
          ...
          let sasContainerToken = blob.GetSharedAccessSignature(policy)
          let uri = Uri(blob.Uri, sasContainerToken)
          this.Response.Redirect(string uri)

This works fine until I try to get a file with a nordic character (ø). Then it crashes:

InvalidOperationException: Invalid non-ASCII or control character in header: 0x00F8

    Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameHeaders.ThrowInvalidHeaderCharacter(char ch)
    Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameHeaders.ValidateHeaderCharacters(string headerCharacters)
    Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameHeaders.ValidateHeaderCharacters(StringValues headerValues)
    Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameResponseHeaders.SetValueFast(string key, StringValues value)
    Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameHeaders.Microsoft.AspNetCore.Http.IHeaderDictionary.set_Item(string key, StringValues value)
    Microsoft.AspNetCore.Http.Internal.DefaultHttpResponse.Redirect(string location, bool permanent)
    Microsoft.AspNetCore.Http.HttpResponse.Redirect(string location)
    Microsoft.Extensions.Internal.ObjectMethodExecutor+<>c__DisplayClass33_0.<WrapVoidMethod>b__0(object target, Object[] parameters)
    Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(object target, Object[] parameters)
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker+<InvokeActionMethodAsync>d__12.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker+<InvokeNextActionFilterAsync>d__10.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker+<InvokeInnerFilterAsync>d__14.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeNextResourceFilter>d__22.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
    Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
    Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeFilterPipelineAsync>d__17.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeAsync>d__15.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Builder.RouterMiddleware+<Invoke>d__4.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Authentication.AuthenticationMiddleware+<Invoke>d__6.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware+<Invoke>d__7.MoveNext()

Accessing the generated URI manually (without redirecting) properly returns the file.

How can I work around this?

[Tratcher]

uri.AbsoluteUri will do the proper encoding for everything except the host name and is adequate as long as you're not dealing with IDNs.

[severisv]

That solves it, thanks!