■/* * *防盗链IHttpHandle...... /* * * 防盗链IHttpHandler * * * 增加了对文件关键字的选择(即仅对文件名存在某些关键字或不存在某些关键字进行过滤) * 设置web.config中 * string eWebapp_NoLink 如果文件名符合该正确表态式将进行过滤(不设置对所有进行过滤) * string eWebapp_AllowLink 如果文件名符合该正确表态式将不进行过滤(优先权高于AllowLink,不设置则服从AllowLink) * bool eWebapp_ AllowOnlyFile 如果为False,(默认true)则不允许用户直接对该文件进行访问建议为true * * * :)以下设置均可省略,设置只是为了增加灵活性与体验 * eWebapp_NoLink_Message 错误信息提示:默认为Link From:域名 * eWebapp_Error_Width 错误信息提示图片宽 * eWebapp_Error_Height 错误信息提示图片高 * * * * * http://ewebapp.net */ using System; using System.Web; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Configuration; using System.Text.RegularExpressions; namespace eWebapp { /// /// 防盗链IHttpHandler /// 参考http://www.softat.org/archiver/tid-52114.html /// /// public class NoLink : IHttpHandler { private string eWebapp_NoLink = string.Empty; private string eWebapp_AllowLink = string.Empty; private bool eWebapp_AllowOnlyFile = true; private string eWebapp_NoLink_Message = string.Empty; private bool error = false; public NoLink() { // // TODO: 在此处添加构造函数逻辑 // } public void ProcessRequest(HttpContext context) { eWebapp_NoLink_Message = ConfigurationSettings.AppSettings["eWebapp_NoLink_Message"]; string myDomain = string.Empty; error = errorLink(context,out myDomain); if(Empty(eWebapp_NoLink_Message)) { eWebapp_NoLink_Message = "Link from :" + myDomain; } if(error) { //Jpg(context.Response,eWebapp_NoLink_Message); Jpg(context.Response,eWebapp_NoLink_Message); } else { Real(context.Response,context.Request); } } public bool IsReusable { get { return true; } } /// /// 输出错误信息 /// /// /// private void Jpg(HttpResponse Response,string _word) { int myErrorWidth = _word.Length*15; int myErrorHeight = 16; try { int _myErrorWidth = Convert.ToInt32(ConfigurationSettings.AppSettings["eWebapp_Error_Width"]); if(_myErrorWidth > 0 ) { myErrorWidth = _myErrorWidth; } } catch { } try { int _myErrorHeight = Convert.ToInt32(ConfigurationSettings.AppSettings["eWebapp_Error_Height"]); if(_myErrorHeight > 0 ) { myErrorHeight = _myErrorHeight; } } catch { } Bitmap Img=null; Graphics g=null; MemoryStream ms=null; Img=new Bitmap(myErrorWidth,myErrorHeight); g=Graphics.FromImage(Img); g.Clear(Color.White); Font f=new Font("Arial",9); SolidBrush s=new SolidBrush(Color.Red); g.DrawString(_word,f,s,3,3); ms=new MemoryStream(); Img.Save(ms,ImageFormat.Jpeg); Response.ClearContent(); Response.ContentType="image/Gif"; Response.BinaryWrite(ms.ToArray()); g.Dispose(); Img.Dispose(); Response.End(); } /// /// 输出真实文件 /// /// /// private void Real(HttpResponse response,HttpRequest request) { FileInfo file = new System.IO.FileInfo(request.PhysicalPath); response.Clear(); response.AddHeader("Content-Disposition", "filename=" + file.Name); response.AddHeader("Content-Length", file.Length.ToString()); string fileExtension = file.Extension.ToLower(); //这里选择输出的文件格式 //可以参考http://ewebapp.cnblogs.com/articles/234756.html增加对更多文件格式的支持. switch (fileExtension) { case "mp3": response.ContentType = "audio/mpeg3"; break; case "mpeg": response.ContentType = "video/mpeg"; break; case "jpg": response.ContentType = "image/jpeg"; break; case "bmp": response.ContentType = "image/bmp"; break; case "gif": response.ContentType = "image/gif"; break; case "doc": response.ContentType = "application/msword"; break; case "css": response.ContentType = "text/css"; break; default: response.ContentType = "application/octet-stream"; break; } response.WriteFile(file.FullName); response.End(); } /// /// 确认字符串是否为空 /// /// /// private bool Empty(string _value) { if(_value == null | _value == string.Empty | _value == "") { return true; } else { return false; } } /// /// 检查是否是非法链接 /// /// /// /// private bool errorLink(HttpContext context,out string _myDomain) { HttpResponse response = context.Response; string myDomain = context.Request.ServerVariables["SERVER_NAME"]; _myDomain = myDomain ; string myDomainIp = context.Request.UserHostAddress; eWebapp_NoLink = ConfigurationSettings.AppSettings["eWebapp_NoLink"]; eWebapp_AllowLink = ConfigurationSettings.AppSettings["eWebapp_AllowLink"]; try { eWebapp_AllowOnlyFile = Convert.ToBoolean(ConfigurationSettings.AppSettings["eWebapp_AllowOnlyFile"]); } catch { eWebapp_AllowOnlyFile = true; } if(context.Request.UrlReferrer != null) { //判定referDomain是否存在网站的IP或域名 string referDomain = context.Request.UrlReferrer.AbsoluteUri.Replace(context.Request.UrlReferrer.AbsolutePath,""); string myPath = context.Request.RawUrl; if(referDomain.IndexOf(myDomainIp) >=0 | referDomain.IndexOf(myDomain)>=0) { return false; } else { //这里使用正则表达对规则进行匹配 try { Regex myRegex ; //检查允许匹配 if(!Empty(eWebapp_AllowLink)) { myRegex = new Regex(eWebapp_AllowLink); if(myRegex.IsMatch(myPath)) { return false; } } //检查禁止匹配 if(!Empty(eWebapp_NoLink)) { myRegex = new Regex(eWebapp_NoLink); if(myRegex.IsMatch(myPath)) { return true; } else { return false; } } return true; } catch { //如果匹配出错,链接错误 return true; } } } else { //是否允许直接访问文件 if(eWebapp_AllowOnlyFile) { return false; } else { return true; } } } } } |
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