Handles finding views for ASP.NET MVC on case-sensitive file systems

CaseInsensitiveViewEngine.cs

// Call CaseInsensitiveViewEngine.Register(...) from Global.asax

using System;
using System.Web;
using System.Web.Mvc;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web.Routing;
 
/// <summary>
/// Works around case sensitive file systems by locating
/// views regardless of the case they are in
/// </summary>
public class CaseInsensitiveViewEngine : WebFormViewEngine {
      
    private static string _Root = HttpContext.Current.Server.MapPath("~/");
     
    //adds a new CaseInsensitiveViewEngine to the routes provided
    public static void Register(ViewEngineCollection engines) {
         
        //clear the existing WebForm View Engines
        IViewEngine[] webforms = engines.Where(engine => 
            engine is WebFormViewEngine).ToArray();
        foreach(IViewEngine engine in webforms) 
            ViewEngines.Engines.Remove(engine);
         
        //add the new case-insensitive engine
        ViewEngines.Engines.Add(new CaseInsensitiveViewEngine());
 
    }
      
    //holds all of the actual paths to the required files
    private static Dictionary<string, string> _ViewPaths = 
        new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
      
    //update the path to match a real file
    protected override IView CreateView (ControllerContext controllerContext, 
        string viewPath, string masterPath) {
        viewPath = this._GetActualFilePath(viewPath);
        masterPath = this._GetActualFilePath(masterPath);
        return base.CreateView (controllerContext, viewPath, masterPath);
    }
     
    //finds partial views by detecting matches
    protected override IView CreatePartialView (ControllerContext controllerContext, 
        string partialPath) {
        partialPath = this._GetActualFilePath(partialPath);
        return base.CreatePartialView (controllerContext, partialPath);
    }
      
    //perform a case-insensitive file search
    protected override bool FileExists (ControllerContext context, string virtualPath) {
        virtualPath = this._GetActualFilePath(virtualPath);
        return base.FileExists(context, virtualPath);
    }
      
    //determines (and caches) the actual path for a file
    private string _GetActualFilePath(string virtualPath) {
          
        //check if this has already been matched before
        if (CaseInsensitiveViewEngine._ViewPaths.ContainsKey(virtualPath))
            return CaseInsensitiveViewEngine._ViewPaths[virtualPath];
  
        //break apart the path
        string[] segments = virtualPath.Split(new char[] { '/' });
          
        //get the root folder to work from
        var folder = new DirectoryInfo(CaseInsensitiveViewEngine._Root);
          
        //start stepping up the folders to replace with the correct cased folder name
        for(int i = 0; i < segments.Length; i++) {
            string part = segments[i];
            bool last = i == segments.Length - 1;
              
            //ignore the root
            if (part.Equals("~")) continue;
              
            //process the file name if this is the last segment
            else if (last) part = this._GetFileName(part, folder);
              
            //step up the directory for another part
            else part = this._GetDirectoryName(part, ref folder);
              
            //if no matches were found, just return the original string
            if (part == null || folder == null) return virtualPath;
              
            //update the segment with the correct name
            segments[i] = part;
              
        }
          
        //save this path for later use
        virtualPath = string.Join("/", segments);
        CaseInsensitiveViewEngine._ViewPaths.Remove(virtualPath);
        CaseInsensitiveViewEngine._ViewPaths.Add(virtualPath, virtualPath);
        return virtualPath;
    }
      
    //searches for a matching file name in the current directory
    private string _GetFileName(string part, DirectoryInfo folder) {
          
        //try and find a matching file, regardless of case
        FileInfo match = folder.GetFiles().FirstOrDefault(file => 
            file.Name.Equals(part, StringComparison.OrdinalIgnoreCase));
        return match is FileInfo ? match.Name : null;
    }
      
    //searches for a folder in the current directory and steps up a level
    private string _GetDirectoryName(string part, ref DirectoryInfo folder) {
        folder = folder.GetDirectories().FirstOrDefault(dir => 
            dir.Name.Equals(part, StringComparison.OrdinalIgnoreCase));
        return folder is DirectoryInfo ? folder.Name : null;
    }
      
}