asp.net怎样提高首页性能

一、自定义Response.Filter得到输出流stream生成动态页面的静态内容(磁盘缓存)
如下的代码我们可以看出，我们以 request.RawUrl 为缓存基础，因为它可以包含任意的QueryString变量，然后我们用MD5加密RawUrl 得到服务器本地文件名的变量，再实例化一个FileInfo操作该文件，如果文件最后一次生成时间小于7天，我们就使用.Net2.0新增的TransmitFile方法将存储文件的静态内容发送到浏览器。如果文件不存在，我们就操作 response.Filter 得到的 Stream 传递给 CommonFilter 类，并利用FileStream写入动态页面的内容到静态文件中。
namespace ASPNET_CL.Code.HttpModules {
public class CommonModule : IHttpModule {
public void Init( HttpApplication application ) {
application.BeginRequest += Application_BeginRequest;
}

private void Application_BeginRequest( object sender, EventArgs e ) {
var context = HttpContext.Current;
var request = context.Request;
var url = request.RawUrl;

var response = context.Response;
var path = GetPath( url );
var file = new FileInfo( path );

if ( DateTime.Now.Subtract( file.LastWriteTime ).TotalDays return;
}
try {
var stream = file.OpenWrite();
response.Filter = new CommonFilter( response.Filter, stream );
}
catch ( Exception ) {
//Log.Insert("");
}
}

public void Dispose() {

}

private static string GetPath( string url ) {
var hash = Hash( url );
string fold = HttpContext.Current.Server.MapPath( "~/Temp/" );
return string.Concat( fold, hash );
}

private static string Hash( string url ) {
url = url.ToUpperInvariant();
var md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
var bs = md5.ComputeHash( Encoding.ASCII.GetBytes( url ) );
var s = new StringBuilder();
foreach ( var b in bs ) {
s.Append( b.ToString( "x2" ).ToLower() );
}
return s.ToString();
}
}
}

二、页面GZIP压缩
对页面GZIP压缩几乎是每篇讲解高性能WEB程序的几大做法之一，因为使用GZIP压缩可以降低服务器发送的字节数，能让客户感觉到网页的速度更快也减少了对带宽的使用情况。当然，这里也存在客户端的浏览器是否支持它。因此，我们要做的是，如果客户端支持GZIP，我们就发送GZIP压缩过的内容，如果不支持，我们直接发送静态文件的内容。幸运的是，现代浏览器IE6.7.8.0，火狐等都支持GZIP。
为了实现这个功能，我们需要改写上面的 Application_BeginRequest 事件：
private void Application_BeginRequest( object sender, EventArgs e ) {
var context = HttpContext.Current;
var request = context.Request;
var url = request.RawUrl;

var response = context.Response;
var path = GetPath( url );
var file = new FileInfo( path );

// 使用页面压缩
ResponseCompressionType compressionType = this.GetCompressionMode( request );
if ( compressionType != ResponseCompressionType.None ) {
response.AppendHeader( "Content-Encoding", compressionType.ToString().ToLower() );
if ( compressionType == ResponseCompressionType.GZip ) {
response.Filter = new GZipStream( response.Filter, CompressionMode.Compress );
}
else {
response.Filter = new DeflateStream( response.Filter, CompressionMode.Compress );
}
}

if ( DateTime.Now.Subtract( file.LastWriteTime ).TotalMinutes return;
}
try {
var stream = file.OpenWrite();
response.Filter = new CommonFilter( response.Filter, stream );
}
catch ( Exception ) {
//Log.Insert("");
}
}

private ResponseCompressionType GetCompressionMode( HttpRequest request ) {
string acceptEncoding = request.Headers[ "Accept-Encoding" ];
if ( string.IsNullOrEmpty( acceptEncoding ) )
return ResponseCompressionType.None;

acceptEncoding = acceptEncoding.ToUpperInvariant();

if ( acceptEncoding.Contains( "GZIP" ) )
return ResponseCompressionType.GZip;
else if ( acceptEncoding.Contains( "DEFLATE" ) )
return ResponseCompressionType.Deflate;
else
return ResponseCompressionType.None;
}

private enum ResponseCompressionType {
None,
GZip,
Deflate
}

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