Disable chunking in ASP.NET Core

Question

I'm using an ASP.NET Core Azure Web App to provide a RESTful API to a client, and the client doesn't handle chunking correctly.

Is it possible to completely turn off Transfer-Encoding: chunked, either at the controller level or in file web.config?

I'm returning a JsonResult somewhat like this:

[HttpPost]
[Produces("application/json")]
public IActionResult Post([FromBody] AuthRequest RequestData)
{
    AuthResult AuthResultData = new AuthResult();

    return Json(AuthResultData);
}

Answer 1

How to get rid of chunking in .NET Core 2.2:

The trick is to read the response body into your own MemoryStream, so you can get the length. Once you do that, you can set the content-length header, and IIS won't chunk it. I assume this would work for Azure too, but I haven't tested it.

Here's the middleware:

public class DeChunkerMiddleware
{
    private readonly RequestDelegate _next;

    public DeChunkerMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var originalBodyStream = context.Response.Body;
        using (var responseBody = new MemoryStream())
        {
            context.Response.Body = responseBody;
            long length = 0;
            context.Response.OnStarting(() =>
            {
                context.Response.Headers.ContentLength = length;
                return Task.CompletedTask;
            });
            await _next(context);

            // If you want to read the body, uncomment these lines.
            //context.Response.Body.Seek(0, SeekOrigin.Begin);
            //var body = await new StreamReader(context.Response.Body).ReadToEndAsync();

            length = context.Response.Body.Length;
            context.Response.Body.Seek(0, SeekOrigin.Begin);
            await responseBody.CopyToAsync(originalBodyStream);
        }
    }
}

Then add this in Startup:

app.UseMiddleware<DeChunkerMiddleware>();

It needs to be before app.UseMvC().

Answer 2

In ASP.NET Core, this seems to work across hosts:

response.Headers["Content-Encoding"] = "identity";
response.Headers["Transfer-Encoding"] = "identity";

Indicates the identity function (i.e., no compression, nor modification). This token, except if explicitly specified, is always deemed acceptable.

• Content-Encoding
• Transfer-Encoding

This also works when you explicitly disable response buffering:

var bufferingFeature = httpContext.Features.Get<IHttpBufferingFeature>();
bufferingFeature?.DisableResponseBuffering();