Session Manager - 为每个页面生成唯一的sessionID

  1 using System;
  2 using System.Collections;
  3 using System.Configuration;
  4 using System.Web;
  5 using System.Web.UI;
  6 using System.Web.UI.WebControls;
  7 using System.Net;
  8 
  9 using TFSBussTier.objects;
 10 
 11 namespace TFSBussTier.bussTier
 12 {
 13 
 14     /// <summary>
 15     /// To Manage the session
 16     /// </summary>
 17     public class SessionMgr
 18     {       
 19         // Session Identity for different page
 20         public readonly string pageIdentity = "PageIdentity";                
 21 
 22         // Private instance for Session Manager
 23         private static SessionMgr instance = null;    
 24     
 25         // Http context for current request
 26         private HttpContext context;
 27 
 28         //private static Hashtable excludeSessions;
 29         private static string []excludeSessions;
 30             
 31 
 32         public SessionMgr()
 33         { 
 34           //excludeSessions.Add("CountryCode","CountryCode");
 35             excludeSessions = new string[]{
 36                 "CountryCode",
 37                 "CTaxINI",
 38                 "iErrorLogID",
 39                 "LoginDefault",
 40                 "StaffID",
 41                 "TFSSysAdmin",
 42                 "TFSUser"
 43                                           };
 44         }   
 45    
 46         /// <summary>
 47         /// Singleton instance for Session manager
 48         /// </summary>
 49         public static SessionMgr Instance
 50         {
 51             get
 52             {
 53                 if(instance == null)
 54                 {
 55                     instance = new SessionMgr();
 56                 }                
 57 
 58                 return instance;
 59             }
 60         }        
 61 
 62     
 63         /// <summary>
 64         /// Initial the session manager to add a parameter to the request url
 65         /// </summary>
 66         public void InitialSessionMgr()
 67         {      
 68             try
 69             {
 70                 context = HttpContext.Current;
 71                 
 72                 string    newPageUrl;
 73                 bool    needRedirect = true;
 74                 string    sKey;
 75                 int        sValue = 0;            
 76                 string    pageUrl = context.Request.Url.ToString();        
 77                                  
 78                 if (context.Request[pageIdentity] == null)
 79                 {
 80                     needRedirect = true;
 81                     sKey = pageUrl;
 82 
 83                     if (context.Session[pageIdentity] != null)               
 84                     {
 85                         sValue = int.Parse(context.Session[pageIdentity].ToString());
 86                     }
 87 
 88                     sValue++;               
 89                 }
 90                 else
 91                 {
 92                     needRedirect = false;
 93                     sKey = GetOrginalPageUrl(pageUrl);     
 94 
 95                     // To process special scenarios:
 96                     // Scenario1: User reinput the url in IE's address box.
 97                     // Scenario2: User copied one url and paste it in a new tab                    
 98                     if(context.Request.UrlReferrer == null || context.Request.UrlReferrer.ToString().Trim().Length ==0)                        
 99                     {    
100                         RedirectToUrl(sKey);
101                     }
102                     else
103                     {
104                         string s = GetOrginalPageUrl(context.Request.UrlReferrer.ToString());
105                         string s2 = GetOrginalPageUrl(pageUrl);
106                         bool equal = s == s2;
107                         //System.Diagnostics.Debug.Write("UrlReferrer["+ s +"] == Request[" +s2+ "]? " + equal.ToString()+"\n");
108                     }
109                 }        
110 
111                 if(needRedirect)
112                 {        
113                     context.Session[pageIdentity] = sValue;    
114                     newPageUrl = sKey + (sKey.IndexOf("?") > -1 ? "&" : "?") + pageIdentity + "=" + sValue;
115 
116                     //need to do: use script2 to redirect the page                
117                     RedirectToUrl(newPageUrl);
118                 }    
119             }
120             catch(Exception ex)
121             {
122                 //Log Error
123                 AddErrorLog("Session manager is initialized failed! - " + ex.ToString());
124             }
125         }
126 
127     
128 
129         /// <summary>
130         /// Redirect to new url
131         /// </summary>
132         /// <param name="context">current http context</param>
133         /// <param name="url">new page url</param>
134         private void RedirectToUrl(string url)
135         {
136             /*        
137                     string script = "<script language=javascript>" +
138                         "window.onload=function(){" +
139                         "var tempa = document.createElement('a');" +
140                         "tempa.href = '"+ sKey +"';" +
141                         "document.getElementsByTagName('body')[0].appendChild(tempa);" +
142                         "tempa.click();" +
143                         "}" +
144                         "</script>";
145             */
146 
147             // We don't use javascript event "window.onload" to process the page redirection.
148             // Thus we won't affect the exists client script in the page    
149             string script4 = @"<script language=javascript>
150                     var counter=0,timer;
151                     if(window != null)
152                     {
153                         timer = window.setInterval(forceToRedirect,100);
154                     }
155         
156                     function forceToRedirect()
157                     {
158                         if(window.document != null && counter < 1)
159                         {
160                             counter++;
161                             clearTimeout(timer);
162                             redirectToUrl('" + url + @"');
163                         }
164                     }
165                     </script>";
166 
167                 HttpContext.Current.Response.Write(script4);    
168             
169         }
170 
171 
172 
173         /// <summary>
174         /// Get session object by the index "key"
175         /// </summary>
176         public object this[string key]
177         {
178             get
179             {        
180                 string k = GetSessionKey(key);                
181                 return HttpContext.Current.Session[k];
182             }
183             set
184             {
185                 string k = GetSessionKey(key);
186                 HttpContext.Current.Session[k] = value;
187             }
188         }
189 
190         /// <summary>
191         /// Get session identity by orginal key
192         /// </summary>
193         /// <param name="key">orginal key</param>
194         /// <returns></returns>
195         private string GetSessionKey(string key)
196         {            
197             for(int i = 0; i<excludeSessions.Length;i++)
198             {
199                 if(excludeSessions[i] == key)
200                 {
201                     return key;
202                 }
203             }
204             
205             return this.GetSessionIdentity(key);            
206         }
207 
208         /// <summary>
209         /// Get the session identity by the key prefix
210         /// </summary>
211         /// <param name="orgKey">key prefix</param>
212         /// <returns>Session identity</returns>
213         public string GetSessionIdentity(string orgKey)
214         {
215             string newSessionkey;
216             if (HttpContext.Current.Request[pageIdentity] == null)
217             {   
218                 //Log Error
219                 //AddErrorLog("Session manager for child window initialized failed! - " + HttpContext.Current.Request.Url.ToString());
220                 return "EmptyKey";
221             }
222 
223             newSessionkey = orgKey + "_" + HttpContext.Current.Request[pageIdentity].ToString();       
224             return newSessionkey;
225         }
226         
227         /// <summary>
228         /// Get the original url, remove the url parameter "pageIdentity"
229         /// </summary>
230         /// <param name="url">request.url</param>
231         /// <returns>url</returns>
232         private string GetOrginalPageUrl(string url)
233         {            
234             string orgUrl = url.IndexOf("?") > -1 ? url.Substring(0,url.IndexOf("?")) : url;
235             return orgUrl;
236         }
237         
238         /// <summary>
239         /// Add error log when error occurs in session manager
240         /// </summary>
241         /// <param name="errorMsg">Error message</param>
242         /// <returns>true or false</returns>
243         private bool AddErrorLog(string errorMsg)
244         {
245             TFSUser objUser=null;
246             if(context.Session!=null && context.Session.Keys.Count!=0 && context.Session["TFSUser"] != null)
247             {
248                 objUser = (TFSUser) context.Session["TFSUser"];
249             }
250             string sStaffID = "SYSTEM";
251             if(objUser!=null)
252             {
253                 sStaffID = objUser.StaffID;
254             }
255 
256             return LogMgr.addErrorLog(errorMsg, sStaffID);
257         }
258        
259     }
260 }
261