Asp.net程序优化js、css实现合并与压缩的方法

本文实例讲述了Asp.net程序优化js、css实现合并与压缩的方法。分享给大家供大家参考。具体实现方法如下：

访问时将js和css压缩并且缓存在客户端,
采用的是Yahoo.Yui.Compressor组件来完成的,用户可以点击此处本站下载。

创建一个IHttpHandler来处理文件

public class CombineFiles : IHttpHandler

{

        private const string CacheKeyFormat = "_CacheKey_{0}_";

        private const bool IsCompress = true; //需要压缩
        public bool IsReusable

        {

            get

            {

                return false;

            }

        }
        public void ProcessRequest(HttpContext context)

        {

            HttpRequest request = context.Request;

            HttpResponse response = context.Response;
            string cachekey = string.Empty;
            string type = request.QueryString["type"];

            if (!string.IsNullOrEmpty(type) && (type == "css" || type == "js"))

            {

                if (type == "js")

                {

                    response.ContentType = "text/javascript";
                }

                else if (type == "css")

                {

                    response.ContentType = "text/css";

                }
                cachekey = string.Format(CacheKeyFormat, type);
                CompressCacheItem cacheItem = HttpRuntime.Cache[cachekey] as CompressCacheItem;

                if (cacheItem == null)

                {

                    string content = string.Empty;

                    string path = context.Server.MapPath("");

                    //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

                    //这里就将所的有文件都请求压缩

                    string[] files = Directory.GetFiles(path, "*." + type);

                    StringBuilder sb = new StringBuilder();

                    foreach (string fileName in files)

                    {

                        if (File.Exists(fileName))

                        {

                            string readstr = File.ReadAllText(fileName, Encoding.UTF8);

                            sb.Append(readstr);

                        }

                    }
                    content = sb.ToString();
                    // 开始压缩文件

                    if (IsCompress)

                    {

                        if (type.Equals("js"))

                        {

                            content = JavaScriptCompressor.Compress(content);

                        }

                        else if (type.Equals("css"))

                        {

                            content = CssCompressor.Compress(content);

                        }

                    }
                    //输入到客户端还可以进行Gzip压缩 ,这里就省略了
                    cacheItem = new CompressCacheItem() { Type = type, Content = content, Expires = DateTime.Now.AddDays(30) };

                    HttpRuntime.Cache.Insert(cachekey, cacheItem, null, cacheItem.Expires, TimeSpan.Zero);

                }
                string ifModifiedSince = request.Headers["If-Modified-Since"];

                if (!string.IsNullOrEmpty(ifModifiedSince)

                    && TimeSpan.FromTicks(cacheItem.Expires.Ticks - DateTime.Parse(ifModifiedSince).Ticks).Seconds < 0)

                {

                    response.StatusCode = (int)System.Net.HttpStatusCode.NotModified;

                    response.StatusDescription = "Not Modified";

                }

                else

                {

                    response.Write(cacheItem.Content);

                    SetClientCaching(response, cacheItem.Expires);

                }

            }

        }
        private void SetClientCaching(HttpResponse response, DateTime expires)

        {

            response.Cache.SetETag(DateTime.Now.Ticks.ToString());

            response.Cache.SetLastModified(DateTime.Now);
            //public 以指定响应能由客户端和共享（代理）缓存进行缓存。    

            response.Cache.SetCacheability(HttpCacheability.Public);
            //是允许文档在被视为陈旧之前存在的最长绝对时间。 

            response.Cache.SetMaxAge(TimeSpan.FromTicks(expires.Ticks));
            response.Cache.SetSlidingExpiration(true);

        }

        private class CompressCacheItem

        {

            /// <summary>

            /// 类型 js 或 css 

            /// </summary>

            public string Type { get; set; } // js css  

            /// <summary>

            /// 内容

            /// </summary>

            public string Content { set; get; }

            /// <summary>

            /// 过期时间

            /// </summary>

            public DateTime Expires { set; get; }

        }

}

最后在配置文件中配置一下CombineFiles.axd文件，具体配置略

引用如下

<script type="text/javascript" src="/js/CombineFiles.axd?type=js"></script>

<link rel="stylesheet" type="text/css" href="/css/CombineFiles.axd?type=css" />

希望本文所述对大家的asp.net程序设计有所帮助。