简单实现asp.net页面压缩(gzip,deflate)

虽然现在带宽上去了，但能减少一些流量总还是好的，特别是手机上网用户。

博客圆里已经有很多现成的gzip页面压缩的模块，也很好用，功能也很强；不过，正因为强了，可能需要做一些配置操作。所以如果只需要简单的对asp.net页面进行压缩的处理，可以试试下面的代码：

Public Class CompressModule
    Implements IHttpModule
    Public Sub Dispose() Implements System.Web.IHttpModule.Dispose

    End Sub

    Public Sub Init(ByVal context As System.Web.HttpApplication) Implements System.Web.IHttpModule.Init
        AddHandler context.PreRequestHandlerExecute, AddressOf CompressModule_PreRequestHandlerExecute
    End Sub

    Protected Sub CompressModule_PreRequestHandlerExecute(ByVal sender As Object, ByVal e As EventArgs)
        Dim app As HttpApplication = CType(sender, HttpApplication)
        '检测是否为ASP.NET页面，是否MS-AJAX应用
        If TypeOf app.Context.CurrentHandler Is UI.Page AndAlso app.Request.ServerVariables("HTTP_X_MICROSOFTAJAX") Is Nothing Then
            Dim type As CompressType = Me.GetCompressType(app)
            If type = CompressType.GZip Then
                app.Response.Filter = New GZipStream(app.Response.Filter, CompressionMode.Compress)
                app.Response.AppendHeader("Content-Encoding", type.ToString().ToLower())
            ElseIf type = CompressType.Deflate Then
                app.Response.Filter = New DeflateStream(app.Response.Filter, CompressionMode.Compress)
                app.Response.AppendHeader("Content-Encoding", type.ToString().ToLower())
            End If
        End If
    End Sub

    ''' <summary>
    ''' 获取客户端支持的压缩类型
    ''' </summary>
    ''' <param name="context">The context.</param>
    ''' <returns></returns>
    Protected Function GetCompressType(ByVal context As HttpApplication) As CompressType
        Dim accept As String = context.Request.Headers("Accept-Encoding")
        If String.IsNullOrEmpty(accept) Then
            Return CompressType.None
        End If
        accept = accept.ToUpperInvariant()
        If accept.Contains("GZIP") Then
            Return CompressType.GZip
        End If
        If accept.Contains("DEFLATE") Then
            Return CompressType.Deflate
        End If
        Return CompressType.None
    End Function


    ''' <summary>
    ''' 压缩类型枚举
    ''' </summary>
    Protected Enum CompressType
        ''' <summary>
        ''' GZIP压缩
        ''' </summary>
        GZip
        ''' <summary>
        ''' Deflate压缩
        ''' </summary>
        Deflate
        ''' <summary>
        ''' 不支持压缩
        ''' </summary>
        None
    End Enum
End Class

编译后，并在web.config文件中添加httpmodule模块配置内容就OK了。

当然也可能将以上代码作出一些修改后直接添加到您的页面基类里使用。