System.IO.InvalidDataException: Multipart body length limit 16384 exceeded.

[eliezeralmeida]

Problem

I'm not able to upload a 50 mb file. The request is being accepted by Kestrel, but when using the MultipartReader class a threshold error occurs.

Analyzing the aspnetcore code the exception occurs due to the limit defined in MultipartReader, and I am defining it as int.MaxValue.

I'm using DotNet 5.0.100-rc.1.20452.10

The Code was based on this example:
https://github.com/dotnet/AspNetCore.Docs/tree/master/aspnetcore/mvc/models/file-uploads/samples

My code

Part of the code that occurs the exception, some words are in Portuguese, but the important thing is in English.

My Kestrel configuration

AspNetCore MultipartReaderStream

StackTrace

System.IO.InvalidDataException: Multipart body length limit 16384 exceeded. at Microsoft.AspNetCore.WebUtilities.MultipartReaderStream.UpdatePosition(Int32 read) at Microsoft.AspNetCore.WebUtilities.MultipartReaderStream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken) at Microsoft.AspNetCore.WebUtilities.StreamHelperExtensions.DrainAsync(Stream stream, ArrayPool1 bytePool, Nullable1 limit, CancellationToken cancellationToken) at Microsoft.AspNetCore.WebUtilities.MultipartReader.ReadNextSectionAsync(CancellationToken cancellationToken) at Releases.Api.Controladores.VersaoSoftwareItemControlador.ConteudoAnexo(Guid itemId) in C:\Users\eliez\source\repos\FusionReleases\src\Releases.Api\Controladores\VersaoSoftwareItemControlador.cs:line 77 at lambda_method5(Closure , Object ) at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask1 actionResultValueTask)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

HEADERS

Cache-Control: no-cache
Connection: keep-alive
Content-Type: multipart/form-data; boundary=--------------------------687707978948167667470949
Accept: /
Accept-Encoding: gzip, deflate, br
Host: localhost:53206
Referer: http://localhost:53106/releases-itens/ef59de1f-616a-4db3-8d95-c63d674c5781/update-anexo
User-Agent: PostmanRuntime/7.26.5
Content-Length: 57822091
Postman-Token: 6344c39b-1fd6-4b0a-be26-e0e13b5dfc2f`

[Tratcher]

That usually means the boundary is wrong so it can't find the start of the first section. There's a non-configurable 16kb limit for how much preamble data it will search looking for the first boundary marker. Can you share the first few lines of the request body?

[eliezeralmeida]

Sorry @Tratcher, I'm trying to find a way to extract these lines, but I'm not finding it. In tests I'm using Postman.

I also tried to extract the lines by code but I didn't get a readable string.
I found this at the postman.

[Tratcher]

That second picture shows the boundary set in the header is -----541608..., but the boundary used in the body is -----postman. That would explain the issue, those two must match for the server to be able to parse the body.

[eliezeralmeida]

I sent it using HttpClient, so I assume it’s something on Postman, I’ll research about.