Asp.net 程序优化js，css合并与压缩

访问时将js和css压缩并且缓存在客户端,
采用的是Yahoo.Yui.Compressor组件还完成的,从这里可下载

创建一个IHttpHandler来处理文件

  1 public class CombineFiles : IHttpHandler
  2     {
  3         private const string CacheKeyFormat = "_CacheKey_{0}_";
  4 
  5         private const bool IsCompress = true; //需要压缩
  6 
  7         public bool IsReusable
  8         {
  9             get
 10             {
 11                 return false;
 12             }
 13         }
 14 
 15         public void ProcessRequest(HttpContext context)
 16         {
 17             HttpRequest request = context.Request;
 18             HttpResponse response = context.Response;
 19 
 20             string cachekey = string.Empty;
 21 
 22             string type = request.QueryString["type"];
 23             if (!string.IsNullOrEmpty(type) && (type == "css" || type == "js"))
 24             {
 25                 if (type == "js")
 26                 {
 27                     response.ContentType = "text/javascript";
 28 
 29                 }
 30                 else if (type == "css")
 31                 {
 32                     response.ContentType = "text/css";
 33                 }
 34 
 35                 cachekey = string.Format(CacheKeyFormat, type);
 36 
 37                 CompressCacheItem cacheItem = HttpRuntime.Cache[cachekey] as CompressCacheItem;
 38                 if (cacheItem == null)
 39                 {
 40                     string content = string.Empty;
 41                     string path = context.Server.MapPath("");
 42                     //找到这个目录下所有的js或css文件，当然也可以进行配置，需求请求压缩哪些文件
 43                     //这里就将所的有文件都请求压缩
 44                     string[] files = Directory.GetFiles(path, "*." + type);
 45                     StringBuilder sb = new StringBuilder();
 46                     foreach (string fileName in files)
 47                     {
 48                         if (File.Exists(fileName))
 49                         {
 50                             string readstr = File.ReadAllText(fileName, Encoding.UTF8);
 51                             sb.Append(readstr);
 52                         }
 53                     }
 54 
 55                     content = sb.ToString();
 56 
 57                     // 开始压缩文件
 58                     if (IsCompress)
 59                     {
 60                         if (type.Equals("js"))
 61                         {
 62                             content = JavaScriptCompressor.Compress(content);
 63                         }
 64                         else if (type.Equals("css"))
 65                         {
 66                             content = CssCompressor.Compress(content);
 67                         }
 68                     }
 69 
 70                     //输入到客户端还可以进行Gzip压缩 ,这里就省略了
 71 
 72                     cacheItem = new CompressCacheItem() { Type = type, Content = content, Expires = DateTime.Now.AddDays(30) };
 73                     HttpRuntime.Cache.Insert(cachekey, cacheItem, null, cacheItem.Expires, TimeSpan.Zero);
 74                 }
 75 
 76                 string ifModifiedSince = request.Headers["If-Modified-Since"];
 77                 if (!string.IsNullOrEmpty(ifModifiedSince)
 78                     && TimeSpan.FromTicks(cacheItem.Expires.Ticks - DateTime.Parse(ifModifiedSince).Ticks).Seconds < 0)
 79                 {
 80                     response.StatusCode = (int)System.Net.HttpStatusCode.NotModified;
 81                     response.StatusDescription = "Not Modified";
 82                 }
 83                 else
 84                 {
 85                     response.Write(cacheItem.Content);
 86                     SetClientCaching(response, cacheItem.Expires);
 87                 }
 88             }
 89 
 90         }
 91 
 92         private void SetClientCaching(HttpResponse response, DateTime expires)
 93         {
 94             response.Cache.SetETag(DateTime.Now.Ticks.ToString());
 95             response.Cache.SetLastModified(DateTime.Now);
 96 
 97             //public 以指定响应能由客户端和共享（代理）缓存进行缓存。    
 98             response.Cache.SetCacheability(HttpCacheability.Public);
 99 
100             //是允许文档在被视为陈旧之前存在的最长绝对时间。 
101             response.Cache.SetMaxAge(TimeSpan.FromTicks(expires.Ticks));
102 
103             response.Cache.SetSlidingExpiration(true);
104         }
105         private class CompressCacheItem
106         {
107             /// <summary>
108             /// 类型 js 或 css 
109             /// </summary>
110             public string Type { get; set; } // js css  
111             /// <summary>
112             /// 内容
113             /// </summary>
114             public string Content { set; get; }
115             /// <summary>
116             /// 过期时间
117             /// </summary>
118             public DateTime Expires { set; get; }
119         }
120     }