Response.Flush() throws System.Web.HttpException

Question

I have a HttpHandler that I\'m using to handle certain images on a client\'s website. When I\'m outputting the image stream to the response object and call Flush occasionally an

Answer 1

I realise this is an old post but it came up when I was looking for an answer to a similar issue. The following is largely verbatim from this SO answer. More background info is available at Is Response.End() considered harmful?.

Replace this: HttpContext.Current.Response.End();

With this:

HttpContext.Current.Response.SuppressContent = true;  // Gets or sets a value indicating whether to send HTTP content to the client.
HttpContext.Current.ApplicationInstance.CompleteRequest(); // Causes ASP.NET to bypass all events and filtering in the HTTP pipeline chain of execution and directly execute the EndRequest event.

Answer 2

Personally in your implementation since the next line is Response.End(), just remove the call to Response.Flush() as Response.End() takes care of everything for you.

Answer 3

While I agree with Mitchel - there's little need to call flush as you're about to call End, if you're using this elsewhere, you could try calling Response.IsClientConnnected first.

Gets a value indicating whether the client is still connected to the server.

Answer 4

For future readers..

I ran into this case where Response.End() throws an error because the client is disconnected.

An error occurred while communicating with the remote host. The error code is 0x80070057

Oddly a CRLF in the StatusDescription was causing the connection to close.

Response.StatusDescription = ex.Message;

Cannot insert the value NULL into column '', table ''; column does not allow nulls. INSERT fails.\r\nThe statement has been terminated

Removing it fixed my problem.

Response.StatusDescription = ex.Message.Replace("\r\n", " ");