Minimizing css files

Before I join the language debate I’d like to share something entirely different. My take on optimizing your css files for production.

Making css files production ready is surprisingly simple.  I use the following setup in my applications.

The css compressor (just removes whitespace in this configuration).

public class CssMinifier

    {
        static readonly Regex whitespaceRegex = new Regex(@"\s+", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
 
        // You can uncomment the following line if you're not using css hacks that rely on comment notation.
        //static readonly Regex commentsRegex = new Regex(@"\/\*(.*?)\*\/ ", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
 
        static readonly Regex addLineBreaksRegex = new Regex(@"\} ", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
        static readonly Regex removeLastBreakRegex = new Regex(@"\n$", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
        static readonly Regex trimInsideLeftBracketsRegex = new Regex(@" \{ ", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
        static readonly Regex trimInsideRightBracketsRegex = new Regex(@"; \}", RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.ECMAScript);
 
        public static string Compress(string source)
        {
            source = whitespaceRegex.Replace(source, " ");
 
            // You can uncomment the following line if you're not using css hacks that rely on comment notation.
            //source = commentsRegex.Replace(source, string.Empty);
 
            source = addLineBreaksRegex.Replace(source, "}\r\n");
            source = removeLastBreakRegex.Replace(source, string.Empty);
            source = trimInsideLeftBracketsRegex.Replace(source, " {");
            source = trimInsideRightBracketsRegex.Replace(source, "}");
 
            return source;
        }
    }

(\cf4=”" <\cf1="" list\cf0="" new\cf0="" csslib="\par" >=”" .mappath(folder);\par=”" fileoperations\cf0=”" path=”\cf4″ folder)\par=”" target,=”" stringbuilder\cf0=”" readfolder(\cf4=”" void\cf0=”" static\cf0=”" private\cf0=”" );\par=”" ?\\r\\n?\cf0=”" target.append(\cf5=”" target.append(readfile(fpath));\par=”" fpath);\par=”" \\r\\n\\r\\n?\cf0=”" *=”" \{0\}=”" ?=”" target.appendformat(\cf5=”" fpath)\par=”" readpath(\cf4=”" ??\cf0=”" #endif\par=”" ??\cf1=”" .readalltext(path);\par=”" file\cf0=”" system.io.\cf4=”" #else\par=”" fileoperations.readfile(path);\par=”" return=”" ??\cf7=”" mode.\par=”" production=”" in=”" is=”" app=”" the=”" when=”" disk=”" from=”" read=”" file=”" cache=”" \cf6=”" !debug=”" #if\cf0=”" .mappath(relativepath);\par=”" relativepath)\par=”" readfile(\cf1=”" context.response.write(sb.tostring());\par=”" context.response.write(cssminifier.compress(sb.tostring()));\par=”" context.response.cache.setvaliduntilexpires(true);\par=”" context.response.cache.setexpires(datetime.now.adddays(1));\par=”" context.response.cache.setcacheability(httpcacheability.public);\par=”" mode\par=”" release=”" handler=”" this=”" of=”" results=”" caching=”" start=”" ;\par=”" css?\cf0=”" ?text=”" context.response.contenttype=”\cf5″ cssbase);\par=”" readfolder(sb,=”" ))\par=”" ?application?\cf0=”" (context.request.url.absoluteuri.contains(\cf5=”" ();\par=”" sb=”\cf1″ ];\par=”" ?windows?\cf0=”" windowstheme=”context.Request.QueryString[\cf5" context.response.clear();\par="" context)\par="" httpcontext\cf0="" processrequest(\cf4="" common="" ~="">I will typically have a FileOperations helper class that takes care of common file system things.

public class StylesHandler :IHttpHandler
    {
        private static string windowsTheme;
        private const string CSSBASE = "~/common/css";
 
        public void ProcessRequest(HttpContext context)
        {
            context.Response.Clear();
 
            windowsTheme = context.Request.QueryString["windows"];
 
            StringBuilder sb = new StringBuilder();
 
            if (context.Request.Url.AbsoluteUri.Contains("application"))
                ReadFolder(sb, CSSBASE);
 
            context.Response.ContentType = "text/css";
 
#if !DEBUG //start caching the results of this handler when in release mode
            context.Response.Cache.SetCacheability(HttpCacheability.Public);
            context.Response.Cache.SetExpires(DateTime.Now.AddDays(1));
            context.Response.Cache.SetValidUntilExpires(true);
            context.Response.Write(CssMinifier.Compress(sb.ToString()));
#else
            context.Response.Write(sb.ToString());
#endif
        }
 
        private static string ReadFile(string relativePath)
        {
            string path = FileOperations.MapPath(relativePath);
#if !DEBUG //Cache the file read from disk when the app is in production mode.
            return FileOperations.ReadFile(path);
#else
            return System.IO.File.ReadAllText(path);
#endif
        }
 
        private static void ReadPath(StringBuilder target, string fPath)
        {
            target.AppendFormat("/* {0} */\r\n\r\n", fPath);
            target.Append(ReadFile(fPath));
            target.Append("\r\n");
        }
 
        private static void ReadFolder(StringBuilder target, string folder)
        {
            string path = FileOperations.MapPath(folder);
 
            List<string> csslib =
                new List<string>(Directory.GetFiles(path, "*.css", SearchOption.TopDirectoryOnly));
 
            foreach (string s in csslib)
            {
                ReadPath(target, s);
            }
 
            if(!string.IsNullOrEmpty(windowsTheme))
            {
                ReadPath(target, string.Format("{0}/window_themes/{1}.css", CSSBASE, windowsTheme));
            }
        }
 
 
        public bool IsReusable
        {
            get { return true; }
        }
    }