StaticFileCompression Net5 Synchronous operations are disallowed

Phil · October 27, 2021, 2:18pm

Hi,

When using StaticFileCompression (https://docs.servicestack.net/compression#static-file-compression) on Net5 we get the following error:

fail: ServiceStack.Host.Handlers.StaticFileHandler[0]
  Static file /js/servicestack-client.js forbidden: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.

Seems to be the outputStream.Close which internally uses a non-async “Write” in Dispose

github.com

ServiceStack/ServiceStack/blob/5c6daec3faed17a5907587ffe9ead4827dd75480/src/ServiceStack/Host/Handlers/StaticFileHandler.cs#L265


                            r.SetContentLength(contentLength);
                            await fs.CopyToAsync(outputStream, BufferSize).ConfigAwait();
                            await outputStream.FlushAsync().ConfigAwait();
                        }
                        else
                        {
                            r.AddHeader(HttpHeaders.ContentEncoding, encoding);
                            outputStream = outputStream.CompressStream(encoding);
                            await fs.CopyToAsync(outputStream).ConfigAwait();
                            await outputStream.FlushAsync().ConfigAwait();
                            outputStream.Close();
                        }
                    }
                }
#if !NETCORE
                catch (System.Net.HttpListenerException ex)
                {
                    if (ex.ErrorCode == 1229)
                        return;
                    //Error: 1229 is "An operation was attempted on a nonexistent network connection"
                    //This exception occurs when http stream is terminated by web browser because user

To repro, we created a new 5.12.1 project using the cli (x new web WebApp), and added CompressFilesWithExtensions = { "js", "css" } on the HostConfig. Then run the app on Kestrel and disabling the browser caching to get the error every time we load up the webpage.

Thanks!

mythz · October 27, 2021, 4:39pm

This should be resolved from this commit, this change is now available from v5.12.1+ that’s now available on MyGet.

As the .NET 5 project templates contain a NuGet.Config which is already configured to use the latest pre-release packages on MyGet, you should be able to get the latest version by clearing your NuGet packages cache and re-creating the web template, e.g:

$ nuget locals all -clear
$ x new web WebApp

thx for reporting!