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; }
}
}
