解决uploadify使用时session发生丢失问题的方法

今天在使用uploadify时发现session会发生丢失的情况，经过一番研究发现，其丢失并不是真正的丢失，而是在使用Flash上传控件的时候使用的session机制和asp.net中的不相同。为解决这个问题使用两种方案，下面进行介绍

第一种：修改Gobal
前台aspx页面：

$("#uploadify").uploadify({ 
        'uploader': '/LZKS/Handler/BigFileUpLoadHandler.ashx', 
        'swf': '/LZKS/Scripts/uploadify/uploadify.swf', 
        'cancelImage': '/LZKS/Scripts/uploadify/cancel.png', 
        'queueID': 'fileQueue', 
        //'auto': false, 
        'multi': true, 
        'buttonText': '文件上传', 
        'formData': { 'ASPSESSID': ASPSESSID, 'AUTHID': auth }, 
        'onSelect': function (file) { 
          $('#uploadify').uploadifySettings('formData', { 'ASPSESSID': ASPSESSID, 'AUTHID': auth }); 
          alert(formDate); 
        }, 
        'onComplete': function (file, data, response) { 
        }, 
 
        'onQueueComplete': function () { 
          alert("上传完成！"); 
          $('#fileQueue').attr('style', 'visibility :hidden'); 
        }, 
        'onSelectError': function (file, errorCode, errorMsg) { 
          $('#fileQueue').attr('style', 'visibility :hidden'); 
        }, 
        'onUploadStart': function (file) { 
          $('#fileQueue').attr('style', 'top:200px;left:400px;width:400px;height :400px;visibility :visible'); 
        } 
      }); 
    });

接着修改Gobal中的代码：

protected void Application_BeginRequest(object sender, EventArgs e) 
    { 
      /* we guess at this point session is not already retrieved by application so we recreate cookie with the session id... */ 
      try 
      { 
        string session_param_name = "ASPSESSID"; 
        string session_cookie_name = "ASP.NET_SessionId"; 
 
        if (HttpContext.Current.Request.Form[session_param_name] != null) 
        { 
          UpdateCookie(session_cookie_name, HttpContext.Current.Request.Form[session_param_name]); 
        } 
        else if (HttpContext.Current.Request.QueryString[session_param_name] != null) 
        { 
          UpdateCookie(session_cookie_name, HttpContext.Current.Request.QueryString[session_param_name]); 
        } 
      } 
      catch 
      { 
      } 
 
      try 
      { 
        string auth_param_name = "AUTHID"; 
        string auth_cookie_name = FormsAuthentication.FormsCookieName; 
 
        if (HttpContext.Current.Request.Form[auth_param_name] != null) 
        { 
          UpdateCookie(auth_cookie_name, HttpContext.Current.Request.Form[auth_param_name]); 
        } 
        else if (HttpContext.Current.Request.QueryString[auth_param_name] != null) 
        { 
          UpdateCookie(auth_cookie_name, HttpContext.Current.Request.QueryString[auth_param_name]); 
        } 
 
      } 
      catch 
      { 
      } 
    } 
 
    private void UpdateCookie(string cookie_name, string cookie_value) 
    { 
      HttpCookie cookie = HttpContext.Current.Request.Cookies.Get(cookie_name); 
      if (null == cookie) 
      { 
        cookie = new HttpCookie(cookie_name); 
      } 
      cookie.Value = cookie_value; 
      HttpContext.Current.Request.Cookies.Set(cookie); 
    }

在JS加载前面定义下面两个变量

var auth = "<% = Request.Cookies[FormsAuthentication.FormsCookieName]==null ? string.Empty : Request.Cookies[FormsAuthentication.FormsCookieName].Value %>"; 
 var ASPSESSID = "<%= Session.SessionID %>";

Handler文件代码如下：

 public class BigFileUpLoadHandler : IHttpHandler, IRequiresSessionState 
  { 
    DALFile Fdal = new DALFile(); 
    public void ProcessRequest(HttpContext context) 
    { 
      context.Response.ContentType = "text/plain"; 
      VideoUpLoad(context, CLSOFT.Web.LZKS.Edu.Globe.filename); 
    } 
    public void VideoUpLoad(HttpContext context, string fileFolderName) 
    { 
      context.Response.Charset = "utf-8"; 
      string aaaaaaa=context.Request.QueryString["sessionid"]; 
      HttpPostedFile file = context.Request.Files["Filedata"]; 
      string uploadPath = HttpContext.Current.Server.MapPath(UploadFileCommon.CreateDir(fileFolderName)); 
      if (file != null) 
      { 
        if (!Directory.Exists(uploadPath)) 
        { 
          Directory.CreateDirectory(uploadPath); 
        } 
        Model.ModelFile model = new Model.ModelFile(); 
        model.File_ID = Guid.NewGuid().ToString(); 
        model.File_Name = file.FileName; 
        model.File_Path = UploadFileCommon.CreateDir(fileFolderName); 
        model.File_Size = file.ContentLength; 
        model.File_Extension = file.FileName.Substring(file.FileName.LastIndexOf('.') + 1); 
        model.File_Date = DateTime.Now; 
        model.File_CurrentMan = CLSOFT.Web.LZKS.Edu.Globe.name; 
        file.SaveAs(uploadPath + model.File_Name); 
       
        List<Model.ModelFile> list = null; 
        if (context.Session["File"] == null) 
        { 
          list = new List<Model.ModelFile>(); 
        } 
        else 
        { 
          list = context.Session["File"] as List<Model.ModelFile>; 
        } 
        list.Add(model); 
        context.Session.Add("File", list); 
      } 
      else 
      { 
        context.Response.Write("0"); 
      }  
    }

这段代码的功能是将多文件的信息存到context.Session["File"] as List<Model.ModelFileModel.ModelFile>为文件信息类实现批量上传的信息给Session
第二种方案：直接向后台传递session值

Ext.onReady(function () { 
    Ext.QuickTips.init(); 
    <%--JQuery装载函数--%> 
      $("#uploadify").uploadify({ 
        'uploader': '../Uploadify-v2.1.4/uploadify.swf',//上传swf相对路径 
        'script': '../Service/FileUploadHelper.ashx',//后台上传处理呈现 
        'cancelImg': '../Uploadify-v2.1.4/cancel.png',//取消上传按钮相对路径 
        'checkExisting':true,//服务端重复文件检测 
        'folder': '../UploadFile/',//上传目录 
        'fileExt':'*.jpg;*.png;*.gif;*.bmp',//允许上传的文件格式 
        'fileDesc':'jpg、png、gif、bmp',//文件选择时显示的提示 
        'queueID': 'fileQueue',//上传容器 
        'auto': false, 
        'multi': false,//只允许单文件上传 
        'buttonText':'Choose File', 
        'scriptData': { 'name': '', 'type': '','length':'' },//在加载时此处是null 
        //'onInit':function(){alert("1");},//初始化工作，在Extjs的嵌套中最先触发的函数 
        //选择一个文件后触发 
        'onSelect': function(event, queueID, fileObj) { 
//          alert("唯一标识:" + queueID + "\r\n" + 
//          "文件名：" + fileObj.name + "\r\n" + 
//          "文件大小：" + fileObj.size + "\r\n" + 
//          "创建时间：" + fileObj.creationDate + "\r\n" + 
//          "最后修改时间：" + fileObj.modificationDate + "\r\n" + 
//          "文件类型：" + fileObj.type); 
           $("#uploadify").uploadifySettings("scriptData", { "length": fileObj.size}); //动态更新配(执行此处时可获得值) 
        }, 
        //上传单个文件接收后触发 
        'onComplete': function (event, queueID, fileObj, response, data) { 
           var value = response; 
           if(value==1){ 
           Ext.Msg.alert("提示","上传成功"); 
           } 
           else if(value==0){ 
           Ext.Msg.alert("提示","请选择上传文件"); 
           } 
           else if(value==-1){ 
            Ext.Msg.alert("提示","已存在该文件"); 
           } 
            
         } 
      }); 
    <%-- jQuery装载函数结束--%>

动态的传递参数，并判断是否合法

//动态加载 
  function loadFileType(){ 
  //检测 
  var medianame=Ext.getCmp("eName").getValue(); 
  if(medianame.trim()==""){ 
    Ext.Msg.alert("提示","媒体名称不能为空"); 
    return; 
  } 
  var filetype=Ext.getCmp("eType").getValue(); 
  if(filetype=="" || filetype<0){ 
    Ext.Msg.alert("提示","请选择媒体类型"); 
    return; 
  } 
  //动态更新配(执行此处时可获得值) 
  $("#uploadify").uploadifySettings("scriptData", { "name": medianame,"type":filetype,"sessionuserid":<%=session_userid %> }); 
  //上传开始 
  $('#uploadify').uploadifyUpload(); 
  }

<%=session_userid %>是取后台的一个变量，该变量在加载页面的时候获得了session值。当然也可以在前台直接获得session值。
后台处理程序：

public class FileUploadHelper : IRequiresSessionState, IHttpHandler 
{ 
 
  int nCurrentUserID = -1; 
  public void ProcessRequest(HttpContext context) 
  { 
    try 
    { 
      nCurrentUserID = WebUtil.GetCurrentUserID();//该处的session值得不到 
    } 
    catch (Exception) 
    { 
    } 
    context.Response.ContentType = "text/plain"; 
    context.Response.Charset = "utf-8"; 
 
    string strFilename = string.Empty; 
    int nFiletype = 0; 
    float fFilelength = 0; 
    string strFileExt = string.Empty; 
    string strFilePath = string.Empty; 
    if (context.Request["sessionuserid"] != null) 
    { 
      nCurrentUserID = Convert.ToInt32(context.Request["sessionuserid"].ToString()); 
    } 
    if (context.Request["name"] != null)//获得文件名(动态参数) 
    { 
      strFilename = context.Request["name"].ToString(); 
    } 
    if (context.Request["type"] != null)//获得文件类型（动态参数） 
    { 
      nFiletype = Convert.ToInt32(context.Request["type"].ToString()); 
    } 
    if (context.Request["length"] != null)//获得文件长度（动态参数） 
    { 
      int nEmptFileLength = Convert.ToInt32(context.Request["length"].ToString()); 
      fFilelength = (float)nEmptFileLength / 1024; 
    } 
    if (context.Request["Filename"] != null)//获得文件名（系统自带） 
    { 
      string filename = context.Request["Filename"].ToString(); 
      strFileExt = Path.GetExtension(filename).ToLower();//获得后缀名 
    } 
    HttpPostedFile file = context.Request.Files["Filedata"]; 
    string uploadPath = HttpContext.Current.Server.MapPath(@context.Request["folder"]); 
    //根据当前日期创建一个文件夹 
    string dirName = System.DateTime.Now.ToString("yyyyMMdd"); 
    uploadPath += dirName; 
 
    string tmpRootDir = context.Server.MapPath(System.Web.HttpContext.Current.Request.ApplicationPath.ToString());//获取程序根目录 
 
    if (file != null) 
    { 
      //判断目录是否存在 
      if (!Directory.Exists(uploadPath)) 
      { 
        Directory.CreateDirectory(uploadPath); 
      } 
      //判断文件是否存在 
      strFilePath = uploadPath + "\\" + strFilename + strFileExt; 
      if (!File.Exists(strFilePath)) 
      { 
        //写数据库成功保存文件 
        Media model = new Media(); 
        int newMediaID = -1; 
        model.media_type = nFiletype; 
        model.media_name = strFilename + strFileExt; 
        model.file_path = strFilePath.Replace(tmpRootDir, "");//保存相对目录 
        model.file_length = fFilelength; 
        newMediaID = MediaBLL.AddMadia(model, nCurrentUserID); 
        if (newMediaID > -1)//数据库写入成功 
        { 
          //保存文件 
          file.SaveAs(strFilePath); 
          //下面这句代码缺少的话，上传成功后上传队列的显示不会自动消失 
          context.Response.Write("1"); 
        } 
      } 
      else 
      { 
        context.Response.Write("-1"); 
      } 
    } 
    else 
    { 
      context.Response.Write("0"); 
    } 
  }

这样就可以解决该问题了。

希望这两种方法都能帮助大家顺利解决session丢失问题，谢谢大家的阅读。