Question

I’m using ASP.net MVC 3 and the ASP.net Development Server.

My web app downloads image files from Amazon S3 into a session folder. A user then sees the images in their browser because one of the app’s web pages references the images.

If I then delete the contents of the session folder and re-download the images the application restarts.

It only seems to restart if I’ve looked at the images files in a web page and delete them before re-downloading them. So if I don’t look at them in a web page I can delete them, do the download again and the app won’t restart. Similarly, if I view them in a web page, don’t delete them and just write over them when doing the download, the app doesn’t restart.

Any ideas if there’s a way I can, say, delete them so that the web server doesn’t mind if I then re-download them?

I don’t want to lose the session you see.

Here is the deletion code…

    public static void EmptyFolder(string directory)
    {
        if (!Directory.Exists(directory))
        {
            return;
        }

        DirectoryInfo directoryInfo = new DirectoryInfo(directory);

        EmptyFolder(directoryInfo);
    }

    private static void EmptyFolder(DirectoryInfo directoryInfo)
    {
        foreach (FileInfo file in directoryInfo.GetFiles())
        {
            file.Delete();
        }

        foreach (DirectoryInfo subfolder in directoryInfo.GetDirectories())
        {
            EmptyFolder(subfolder);

            subfolder.Delete();
        }
    }

Answer 1

This is expected behaviour; If you delete a file that exists in the folder context of the website, IIS will restart in-case it has to dynamically recompile anything.

It’s the same as saving a change to Web.Config.

If this is too much of a problem, you need to move the images outside of the Website folder.

Regarding the Session, you can either move the resources like I suggested, or consider switching to SQL session storage, or using the ASP.Net session service; which disconnects it from the website.

Loading the image in a browser causes IIS to bind it to your worker process, likely because of caching, but it’s relevant I guess to ask where the session folder is.

Does your folder structure look similar to this ?

c:\
   inetpub
   |__ + wwwroot
          |__ - MyWebSite
          |__ - SessionFolder

or this ?

c:\
   inetpub
   |__ + wwwroot
          |__ - MyWebSite
                |__ - bin
                |__ - Content
                |__ - Scripts
                |__ - SessionFolder
                |__ - Views
                |__ - web.config
                |__ - global.asax