Many concurrent requests

[cody82]

Description

Nancy can not serve many(<10) concurrent requests at once.

Steps to Reproduce

1. Add a StaticContentsConventions to serve files from a directory.
2. Copy a long video file to the directory.
3. Open the video in your browser in many tabs(>10) by pointing all to e.g. http://localhost/myvideo.mp4.
4. Observe: Video is not displayed on all tabs, instead they wait for a connection till you close other tabs.

System Configuration

• Nancy version: 1.4.1
• Nancy host: OWIN
• Browser: Chrome

[Yantrio]

This screams of a common issue with full iis on non-server windows OS, what version of windows/iis are you running in (if at all)?

[cody82]

Forgot to mention: I am using Selfhosting with Microsoft.Owin.Host.HttpListener.
Maybe thats the Problem?
OS is Windows 10.
What would be the best Option for Selfhosting?

[hey-red]

The best option to use nginx for static content(or another http server).

[sphiecoh]

I agree with @kiri-rin nginx is perfect for static content and then let nancy handle api related stuff.

[cody82]

Well, the problem is that I also have nonstatic content that is large or takes some time to generate.
I understand that this is no common use case though.
I will investigate this further. If someone can give me a hint where the problem could be it would be great.

[thecodejunkie]

@cody82 if you have long running routes then you should make them async so they do not block up the request threads

[cody82]

Yes. So does that mean that the problem is not in the general HTTP request handling in Nancy but in the handler for static files that does not properly use async?

I also experienced the same problem in ServiceStack that does most its handling asynchronous but then it calls one synchronous Socket.Write function that blocks everything.

[cody82]

I have tracked the problem to GenericFileResponse.GetFileContent:

        private static Action<Stream> GetFileContent(string filePath, long length)
        {
            return stream =>
            {
                using (var file = File.OpenRead(filePath))
                {
                    file.CopyTo(stream, (int)(length < BufferSize ? length : BufferSize));
                }
            };
        }

So File.CopyTo blocks the thread while the file/video is transfered.
(Also this class does not seam to handle partial responses but thats another issue.)
I doubt this can be just converted to an async function but I may be wrong?

[danbarua]

(Also this class does not seam to handle partial responses but thats another issue.)

@cody82 I created a PartialFileResponse for video/audio streaming applications: https://gist.github.com/danbarua/0fd9fcad5ec85e0c02dc

Needs a little cleaning up but could possibly be merged in to Nancy or have the functionality added to GenericFileResponse.