Trying to implement IVirtualImageProvider in ImageResizer - asp.net-mvc

Question

I'm trying to implement an IVirtualImageProvider plugin for ImageResizer as explained here. I didn't find the instructions hard to follow, however it doesn't seem like any of my images are passing through the plugin. My images are stored in a Windows folder located outside of the ASP .NET root.
Any image path that starts with "assets" or "images" should be handled by the plugin. Here is my implementation of the IVirtualImageProvider and IVirtualFile interfaces:
namespace ImageResizer.Plugins.Basic
{
public class ResizerVirtFolder : IPlugin, IVirtualImageProvider
{
public IPlugin Install(Configuration.Config c)
{
c.Plugins.add_plugin(this);
return this;
}
public bool Uninstall(Configuration.Config c)
{
c.Plugins.remove_plugin(this);
return true;
}
public bool FileExists(string virtualPath, System.Collections.Specialized.NameValueCollection queryString)
{
return (virtualPath.StartsWith("assets", StringComparison.OrdinalIgnoreCase) || virtualPath.StartsWith("images", StringComparison.OrdinalIgnoreCase));
}
public IVirtualFile GetFile(string virtualPath, System.Collections.Specialized.NameValueCollection queryString)
{
return new ResizerVirtualFile(virtualPath);
}
}
public class ResizerVirtualFile : IVirtualFile
{
public ResizerVirtualFile(string virtualPath)
{
this._virtualPath = virtualPath;
}
protected string _virtualPath;
public string VirtualPath
{
get { return _virtualPath; }
}
public System.IO.Stream Open()
{
string sitePath = System.Configuration.ConfigurationManager.AppSettings["PageFilesLocation"];
_virtualPath = _virtualPath.Contains("assets/") ? _virtualPath.Substring(_virtualPath.IndexOf("assets/") + 7) : _virtualPath;
string assetPath = Path.Combine(sitePath, _virtualPath.TrimStart('/').Replace("/", #"\"));
System.IO.FileStream oStream = new FileStream(assetPath, FileMode.Open);
return oStream;
}
}
}
Here's a brief snippet of the Web.config modification I made for the plugin:
<resizer>
<plugins>
<add name="MvcRoutingShim" />
<add name="ResizerVirtFolder" />
</plugins>
</resizer>
ImageResizer.Plugins.Basic.ResizerVirtFolder shows up under registered plugins when I go to resizer.debug.ashx, so I believe that means the plugin is loaded. However, when I put a breakpoint on the FileExists or GetFile functions, it isn't triggered.
I thought to use the VirtualFolder plugin, but it doesn't look like it's included in the download any more. I'm using v 3.4.3.
Edit: Added link to the debug output Gist here.
Longer Edit: I should add that the images that are not showing up do not have query strings in their requests and are not being resized in any way. Does that mean that ImageResizer will not look at them at all, and as a result, the Virtual Image Provider's functions will not be executing in this case?
Another Edit: Looking at this page, it seems like the simplest way to get the images to work in ImageResizer might be to add a different prefix rather than /assets or /images, like perhaps /resize. In this case, should I add an ignore route for /resize or not? There is a route handler provided by my CMS which will eventually try to deal with this route if I do not ignore it.

Answer 1

Well, looks like I found my own solution. Here's the problem:
return (virtualPath.StartsWith("assets", StringComparison.OrdinalIgnoreCase)
StartsWith will always return false because the virtualPath will start with my hostname. Switching to a Contains() statement has this working perfectly.
Great plugin, by the way!