即使 ASP.NET 身份验证清楚地表明您必须进行二次检查以确认用户是否仍然是活跃的登录用户(例如,我们可以阻止用户,用户可能已经更改了他的密码),表单身份验证票对这些事情不提供任何安全保障。
UserSession与ASP.NET MVC Session无关,这里只是一个名字
我实施的解决方案是,
- 用
UserSessionID (PK, Identity) UserID (FK) DateCreated, DateUpdated在数据库中创建UserSessions表
- FormsAuthenticationTicket 有一个名为 UserData 的字段,您可以在其中保存 UserSessionID。
用户登录时
public void DoLogin(){
// do not call this ...
// FormsAuthentication.SetAuthCookie(....
DateTime dateIssued = DateTime.UtcNow;
var sessionID = db.CreateSession(UserID);
var ticket = new FormsAuthenticationTicket(
userName,
dateIssued,
dateIssued.Add(FormsAuthentication.Timeout),
iSpersistent,
// userData
sessionID.ToString());
HttpCookie cookie = new HttpCookie(
FormsAuthentication.CookieName,
FormsAuthentication.Encrypt(ticket));
cookie.Expires = ticket.Expires;
if(FormsAuthentication.CookieDomain!=null)
cookie.Domain = FormsAuthentication.CookieDomain;
cookie.Path = FormsAuthentication.CookiePath;
Response.Cookies.Add(cookie);
}
授权用户
Global.asax 类可以连接到 Authorize
public void Application_Authorize(object sender, EventArgs e){
var user = Context.User;
if(user == null)
return;
FormsIdentity formsIdentity = user.Identity as FormsIdentity;
long userSessionID = long.Parse(formsIdentity.UserData);
string cacheKey = "US-" + userSessionID;
// caching to improve performance
object result = HttpRuntime.Cache[cacheKey];
if(result!=null){
// if we had cached that user is alright, we return..
return;
}
// hit the database and check if session is alright
// If user has logged out, then all UserSessions should have been
// deleted for this user
UserSession session = db.UserSessions
.FirstOrDefault(x=>x.UserSessionID == userSessionID);
if(session != null){
// update session and mark last date
// this helps you in tracking and you
// can also delete sessions which were not
// updated since long time...
session.DateUpdated = DateTime.UtcNow;
db.SaveChanges();
// ok user is good to login
HttpRuntime.Cache.Add(cacheKey, "OK",
// set expiration for 5 mins
DateTime.UtcNow.AddMinutes(5)..)
// I am setting cache for 5 mins to avoid
// hitting database for all session validation
return;
}
// ok validation is wrong....
throw new UnauthorizedException("Access denied");
}
用户退出时
public void Logout(){
// get the ticket..
FormsIdentity f = Context.User.Identity as FormsIdentity;
long sessionID = long.Parse(f.UserData);
// this will prevent cookie hijacking
var session = db.UserSessions.First(x=>x.UserSessionID = sessionID);
db.UserSession.Remove(session);
db.SaveChanges();
FormsAuthentication.Signout();
}
当用户更改密码或用户被阻止或用户被删除时...
public void ChangePassword(){
// get the ticket..
FormsIdentity f = Context.User.Identity as FormsIdentity;
long sessionID = long.Parse(f.UserData);
// deleting Session will prevent all saved tickets from
// logging in
db.Database.ExecuteSql(
"DELETE FROM UerSessions WHERE UserSessionID=@SID",
new SqlParameter("@SID", sessionID));
}