resize.min.cs - remove UTF-8 byte order mark (which appears in the content of js bundle)

[jirikanda]

resize.min.cs contains byte order mark.
Unfortunately, the content of the file is used in the js bundle and the byte order mark appears in the "middle" of the bundle.
This causes problems on some firewalls/gateways which do not expect this symbol here.

The commit/pull request only removes the byte order mark from the beginning of the resize.min.cs. Thats why the diff of the commit does not look "understandable".

What is byte order mark?
see https://en.wikipedia.org/wiki/Byte_order_mark

[LarsBlaabjerg]

Would be nice if this was merged. It is causing problems with Azure.

[jirikanda]

@LarsBlaabjerg Yes, we also found this issue with Azure. It was solved somehow by the customer's Azure network administrator, but I have no information, how.

As a developer, I found the following awful workaround - use a middleware to remove the BOM.
We did NOT use this at production finally, use it at your own risk.

public class HangfireConsoleJsByteOrderMaskRemovingMiddleware
{
	private RequestDelegate _next;

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

	/// <summary>
	/// The middleware Invoke method.
	/// </summary>
	/// <param name="httpContext">The current <see cref="HttpContext"/>.</param>
	/// <returns>A Task to support async calls.</returns>
	public async Task Invoke(HttpContext httpContext)
	{
		byte[] byteOrderMask = System.Text.UTF8Encoding.UTF8.GetPreamble();
		Stream originalBodyStream = httpContext.Response.Body;
		try
		{
			var memoryStream = new MemoryStream();
			httpContext.Response.Body = memoryStream;

			await _next(httpContext).ConfigureAwait(false);

			memoryStream.Position = 0;
			var content = memoryStream.ToArray();

			int indexOfBom = content.AsSpan().IndexOf(byteOrderMask);
			Contract.Assert(indexOfBom >= 0);

			await originalBodyStream.WriteAsync(content, 0, indexOfBom);
			await originalBodyStream.WriteAsync(content, indexOfBom + byteOrderMask.Length, content.Length - indexOfBom - byteOrderMask.Length);
		}
		finally
		{
			httpContext.Response.Body = originalBodyStream;
		}
	}
}

and register the middleware:

app.UseWhen(context => context.Request.Path.Value.StartsWith("/hangfire/js"), appBuilder =>
{
        appBuilder.UseMiddleware<HangfireConsoleJsByteOrderMaskRemovingMiddleware>();
});