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。