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
代码如下:
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
复制代码 代码如下:<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。
更多信息请查看IT技术专栏
