当我们压缩我的Response后再传到Client端时,可以明显节省宽带. 提升Site的性能. 现在的浏览器大部分都支持Gzip,Deflate压缩. 同时我们还可以删除一些空白
段,空行,注释等以使得HTML文档的尺寸变得更小. 让我们先来实现压缩与删除空白类, 继承自Stream类:
/// <summary> /// CompressWhitespaceFilter /// </summary> public class CompressWhitespaceFilter : Stream { private GZipStream _contentGZipStream; private DeflateStream _content_DeflateStream; private Stream _contentStream; private CompressOptions _compressOptions; /// <summary> /// Initializes a new instance of the <see cref="CompressWhitespaceFilter"/> class. /// </summary> /// <param name="contentStream">The content stream.</param> /// <param name="compressOptions">The compress options.</param> public CompressWhitespaceFilter(Stream contentStream, CompressOptions compressOptions) { if (compressOptions == CompressOptions.GZip) { this._contentGZipStream = new GZipStream(contentStream, CompressionMode.Compress); this._contentStream = this._contentGZipStream; } else if (compressOptions == CompressOptions.Deflate) { this._content_DeflateStream = new DeflateStream(contentStream, CompressionMode.Compress); this._contentStream = this._content_DeflateStream; } else { this._contentStream = contentStream; } this._compressOptions = compressOptions; } public override bool CanRead { get { return this._contentStream.CanRead; } } public override bool CanSeek { get { return this._contentStream.CanSeek; } } public override bool CanWrite { get { return this._contentStream.CanWrite; } } public override void Flush() { this._contentStream.Flush(); } public override long Length { get { return this._contentStream.Length; } } public override long Position { get { return this._contentStream.Position; } set { this._contentStream.Position = value; } } public override int Read(byte[] buffer, int offset, int count) { return this._contentStream.Read(buffer, offset, count); } public override long Seek(long offset, SeekOrigin origin) { return this._contentStream.Seek(offset, origin); } public override void SetLength(long value) { this._contentStream.SetLength(value); } public override void Write(byte[] buffer, int offset, int count) { byte[] data = new byte[count + 1]; Buffer.BlockCopy(buffer, offset, data, 0, count); string strtext = System.Text.Encoding.UTF8.GetString(data); strtext = Regex.Replace(strtext, "^\s*", string.Empty, RegexOptions.Compiled | RegexOptions.Multiline); strtext = Regex.Replace(strtext, "\r\n", string.Empty, RegexOptions.Compiled | RegexOptions.Multiline); strtext = Regex.Replace(strtext, "<!--*.*?-->", string.Empty, RegexOptions.Compiled | RegexOptions.Multiline); byte[] outdata = System.Text.Encoding.UTF8.GetBytes(strtext); this._contentStream.Write(outdata, 0, outdata.GetLength(0)); } } /// <summary> /// CompressOptions /// </summary> /// <seealso cref="http://en.wikipedia.org/wiki/Zcat#gunzip_and_zcat"/> /// <seealso cref="http://en.wikipedia.org/wiki/DEFLATE"/> public enum CompressOptions { GZip, Deflate, None }
上面的代码使用正则表达式替换字符串,你可以修改那些正则表达式来满足你的需求.我们同时使用了GZipStream与DeflateStream实现了压缩.好的,接下来与
HttpModule结合:
/// <summary> /// CompressWhitespaceModule /// </summary> public class CompressWhitespaceModule : IHttpModule { #region IHttpModule Members /// <summary> /// Disposes of the resources (other than memory) used by the module that implements <see cref="T:System.Web.IHttpModule"/>. /// </summary> public void Dispose() { // Nothing to dispose; } /// <summary> /// Initializes a module and prepares it to handle requests. /// </summary> /// <param name="context">An <see cref="T:System.Web.HttpApplication"/> that provides access to the methods, properties, and events common to all application objects within an ASP.NET application</param> public void Init(HttpApplication context) { context.BeginRequest += new EventHandler(context_BeginRequest); } /// <summary> /// Handles the BeginRequest event of the context control. /// </summary> /// <param name="sender">The source of the event.</param> /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param> void context_BeginRequest(object sender, EventArgs e) { HttpApplication app = sender as HttpApplication; if (app.Request.RawUrl.Contains(".aspx")) { HttpContext context = app.Context; HttpRequest request = context.Request; string acceptEncoding = request.Headers["Accept-Encoding"]; HttpResponse response = context.Response; if (!string.IsNullOrEmpty(acceptEncoding)) { acceptEncoding = acceptEncoding.ToUpperInvariant(); if (acceptEncoding.Contains("GZIP")) { response.Filter = new CompressWhitespaceFilter(context.Response.Filter, CompressOptions.GZip); response.AppendHeader("Content-encoding", "gzip"); } else if (acceptEncoding.Contains("DEFLATE")) { response.Filter = new CompressWhitespaceFilter(context.Response.Filter, CompressOptions.Deflate); response.AppendHeader("Content-encoding", "deflate"); } } response.Cache.VaryByHeaders["Accept-Encoding"] = true; } } #endregion }
HttpApplication.BeginRequest 事件是 在 ASP.NET 响应请求时作为 HTTP 执行管线链中的第一个事件发生。
在WEB.CONFIG中你还需要配置:
<httpModules>
<add name = "CompressWhitespaceModule" type= "MyWeb.CompressWhitespaceModule" />
</ httpModules >
我们来看一下效果, 下面没有使用时, 4.8KB