If UserTable Is Nothing Then '创建用于记录登录信息的临时表
ClearTime = Date.Now()
Dim dtb As New DataTableBuilder("UserInfos")
dtb.AddDef("UserName", Gettype(String), 16)
dtb.AddDef("UserID",Gettype(String),16)
dtb.AddDef("ActiveTime",Gettype(Date))
UserTable = dtb.Build(True)
End If
If (Date.Now - ClearTime).TotalMinutes >= 30 Then '清除超过30分钟没有操作的登录信息
UserTable.DeleteFor("ActiveTime < #" & Date.Now.AddMinutes(-30) & "#")
ClearTime = Date.Now()
End If
'身份验证
Dim Verified As Boolean '用于标记用户是否通过了身份验证
Dim UserName As String = e.Cookies("username") '从cookie中获取用户名
Dim Password As String = e.Cookies("password") '从cookie中获取用户密码
If e.Path = "logon.htm" '如果是通过登录页面访问,从PostValues即可中提取用户名和密码
If e.PostValues.ContainsKey("username") AndAlso e.PostValues.ContainsKey("password") Then
UserName = e.PostValues("username")
Password = e.PostValues("password")
End If
End If
If UserName = "张三" AndAlso Password = "888" Then '实际使用的时候,请改为从数据库读取用户名和密码进行比较
Verified = True
ElseIf Username = "李四" AndAlso Password="999" Then
Verified = True
End If
If Verified AndAlso e.Path = "logon.htm" Then '如果用户访问的是登录页,且身份验证成功
wb.AppendCookie("username",UserName) '将用户名和密码写入cookie
wb.AppendCookie("password",Password)
wb.InsertHTML("<meta http-equiv='Refresh' c>") '直接跳转到首页
e.WriteString(wb.Build) '生成网页
Return '必须的
ElseIf Verified = False AndAlso e.Path <> "logon.htm" Then '如果用户身份验证失败,且访问的不是登录页面
wb.InsertHTML("<meta http-equiv='Refresh' c>") '那么直接跳转到登录页面
e.WriteString(wb.Build) '生成网页
Return '必须的
End If