Question

我有生成验证码的代码。我需要检查是否在24小时内生成了该代码。如果有，我需要它重新发送相同的代码。如果超过24小时，我需要它发送另一个代码。所有这些都有效，除了检查代码是在24小时内生成还是在之后生成。如果需要，我可以解释一下代码。

    'This gets the current date
    Dim CurrentDate As Date
    CurrentDate = Today

    'This gets the randomly generated verification code
    For i As Integer = 1 To cnt
        Dim idx As Integer = r.Next(0, s.Length)
        sb.Append(s.Substring(idx, 1))

    'This generates another if the Resend Verification code button is clicked
    Next

    oWebUserGE.SetValue("VerificationCode__pbi", sb.ToString()) 
    oWebUserGE.Save()

    oResultCode.Value = "SUCCESS"
    Catch ex As System.Exception
    oResultCode.Value = "FAILED"
    End Try

Answer 1

如果我没有数据库，我会如何做到这一点。请注意，没有验证检查 - 我留给您。

Imports System.Text

Public Class Form1
Public Sub New()
    ' This call is required by the designer.
    InitializeComponent()
    DoWork()
    ' Add any initialization after the InitializeComponent() call.
End Sub

Private Sub DoWork()
    'Test Case. Receiving a code > 24 hours old.
    Console.WriteLine("Test 1 Start - Old Code")
    Dim sOldVerificationCode As String = GenerateVerificationCode(False)
    Dim bUpdate As Boolean = CheckCode(sOldVerificationCode)
    If bUpdate Then
        Dim sNew As String = GenerateVerificationCode(True)
        Console.WriteLine("Generating New Code. Old Code Expired: " + sNew + Environment.NewLine + "Test Passed")
    Else
        Console.WriteLine("Test Failed.")
    End If
    Console.WriteLine("Test 1 Finished - Old Code" + Environment.NewLine)
    Console.WriteLine("Test 2 Start - New Code")
    'Test Case. Receiving a code < 24 hours old.
    Dim sNewVerificationCode As String = GenerateVerificationCode(True)
    bUpdate = CheckCode(sNewVerificationCode)
    If bUpdate Then
        Console.WriteLine("Test Failed.")
    Else
        Console.WriteLine("Code Is Good. No New Code Generated." + Environment.NewLine + "Test Passed")
    End If
    Console.WriteLine("Test 2 Finished - New Code")
End Sub

Private Function CheckCode(ByVal sOldVerificationCode As String) As Boolean
    Dim sVerCodeRaw As String = System.Net.WebUtility.UrlDecode(sOldVerificationCode) 'Url Decode, back to Base64 string.
    Dim stringBytes As Byte() = Convert.FromBase64String(sVerCodeRaw) 'Get Base64 bytes.
    Dim sVerCode As String = Encoding.UTF8.GetString(stringBytes) 'Get Raw String
    Dim sCode As String = sVerCode.Split("|")(0) 'Code part
    Dim sDate As String = sVerCode.Split("|")(1) 'Date part
    Dim dtOldCode As DateTime = DateTime.Parse(sDate).ToLocalTime()
    Return DateDiff(DateInterval.Day, dtOldCode, DateTime.Now) > 0
End Function

Private Function GenerateVerificationCode(ByVal bNew As Boolean) As String 'Dual purpose so we don't need 2 functions for nearly identical tasks.
    Dim CurrentDate As DateTime = IIf(bNew, DateTime.Now, DateAdd(DateInterval.Day, -2, DateTime.Now))
    Dim sb As New StringBuilder()
    sb.Append(Guid.NewGuid.ToString().Replace("-", "")) 'Unique instead of random. Random is not unique.
    sb.Append("|" + CurrentDate.ToUniversalTime().ToString()) 'Using UTC in case multiple servers in different timezones.
    Dim stringBytes As Byte() = Encoding.UTF8.GetBytes(sb.ToString()) 'Byte array for use in converting to Base64.
    Dim verCodeRaw As String = Convert.ToBase64String(stringBytes) 'now a base64 encoded string. This will make it look like gibberish in the 
    Dim urlVerification As String = System.Net.WebUtility.UrlEncode(verCodeRaw) 'Now URL Safe. Assuming it'll be a Get parameter.
    Return urlVerification
End Function
End Class

输出：

Test 1 Start - Old Code
Old Code Expired. Generating New Code: Y2Q1Nzg0M2VjNTVlNDU3Njk1MDU4OTBiMmI1NTEzN2F8Mi8yMy8yMDE4IDc6NTc6NDYgUE0%3D
Test Passed
Test 1 Finished - Old Code

Test 2 Start - New Code
Code Is Good. No New Code Generated.
Test Passed
Test 2 Finished - New Code

您可以插入断点来检查中间值。

我已将其转换为Base64字符串，然后对其进行URL编码。 这不安全但如果作为GET附加到链接上它看起来会更好。

我还使用了GUID而不是随机数生成器。这保证了唯一值 - 您的随机数生成不保证是唯一的。

检查项目是否在24小时内被修改

1 个答案: