always a good practice to keep a record of errors that occur in any application, I believe that the most common errors is to place a text file as a sort of log, or possibly within of a database to keep track. The more sophisticated there will make the information as an event of windows.
But if we want users of the application that are the curious, seeing and reading errors that occur in our application, a practical way is to encrypt the file. The problem with this is that if the text file becomes too large can slow the encryption application, and you have to open decrypt the file, post a message, and re-encrypt the file. Being
above a little impractical decided best to put the messages encrypted within the file. To modify the class which I am using to save your messages:
1: Public Shared Sub WriteError (ByVal errorMessage As String )
2: Try
3: Dim path As String = "error.txt"
4: If ( Not File.Exists(System.Web.HttpContext.Current.Server.MapPath(path))) Then
5: File.Create(System.Web.HttpContext.Current.Server.MapPath(path)).Close() 6: End If
7: Using w As StreamWriter = File.AppendText(System.Web.HttpContext.Current.Server.MapPath(path))
8: w.WriteLine(Constants.vbCrLf & "Error : " )
9: w.WriteLine ( "{0}" , DateTime.Now.ToString (CultureInfo.InvariantCulture))
10: Dim err As String = "In line:" & System . Web.HttpContext.Current.Request.Url.ToString () & . "Message:" & errorMessage
11: w.WriteLine (Encrypt (err, True))
12: w.WriteLine ( "__________________________" )
13: w.Flush () 14: w.Close() 15: End Using
16: Catch ex As Exception
17: WriteError(ex.Message) 18: End Try
19: End Sub
If you look at line 11 I put the word Encrypt, is there where I'm calling another function, the file imported into the library. NET Cryptography: Imports System.Security.Cryptography
Public Function Encrypt (ByVal toEncrypt As String , ByVal useHashing As Boolean ) As String Dim
keyArray As Byte () Dim
toEncryptArray As Byte () = UTF8Encoding. UTF8.GetBytes (toEncrypt) Dim
key As String = "MyKEY"
If useHashing Then
Dim hashmd5 As New MD5CryptoServiceProvider()
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key))
hashmd5.Clear()
Else keyArray = UTF8Encoding.UTF8.GetBytes(key)
End If
Dim tdes As New TripleDESCryptoServiceProvider()
tdes.Key keyArray
tdes.Mode = = = CipherMode.ECB
tdes.Padding PaddingMode.PKCS7
Dim ctransform The ICryptoTransform tdes.CreateEncryptor = () Dim
resultArray The GB () = cTransform.TransformFinalBlock (toEncryptArray, 0, toEncryptArray.Length)
tdes.Clear () Return
Convert.ToBase64String (resultArray, 0, resultArray.Length) End function
Now we have our encrypted messages. If we want to decrypt messages only have to use the following function somewhere and call it:
Public Shared Function Decrypt (ByVal cipherString As String, ByVal useHashing As Boolean) As String Dim
keyArray As Byte () Dim
toEncryptArray As Byte () = Convert.FromBase64String(cipherString)
Dim key As String = "MyKEY"
If useHashing Then
Dim hashmd5 As New MD5CryptoServiceProvider()
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key))
hashmd5.Clear()
Else keyArray = UTF8Encoding.UTF8.GetBytes(key)
End If
Dim TDES The New TripleDESCryptoServiceProvider ()
tdes.Key keyArray
tdes.Mode = = = CipherMode.ECB
tdes.Padding PaddingMode.PKCS7
Dim ctransform The ICryptoTransform tdes.CreateDecryptor = () Dim
resultArray The Byte () = cTransform.TransformFinalBlock (toEncryptArray, 0, toEncryptArray.Length)
tdes.Clear () Return
UTF8Encoding.UTF8. GetString (resultArray) End Function
} Maybe use an aspx form to receive the encrypted code:
\u0026lt;% @ Page Language = "vb" AutoEventWireup = "false" CodeBehind = "WebForm1.aspx.vb" Inherits = "Bintech . WebForm1 "%> \u0026lt;! DOCTYPE html PUBLIC "- / / W3C / / DTD XHTML 1.0 Transitional / / EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >
< html xmlns ="http://www.w3.org/1999/xhtml" >
< head runat ="server" >
< title > Untitled Page </ title >
</ head >
< body >
< form id ="form1" runat ="server" >
< div >
Forma de desencriptacion: < br />
< asp:TextBox ID ="TextBoxEncriptado" runat ="server" Height ="173px" TextMode ="MultiLine" Width = "308px" > \u0026lt;/ asp: TextBox >
\u0026lt; br />
\u0026lt; asp: Button ID = "Button1"
runat = "server" Text = "Button" >
\u0026lt; br />
\u0026lt; asp: Label ID ="LabelResult" runat ="server" ></ asp:Label ></ div >
</ form >
</ body >
</ html >
and add an event to the button:
Protected Sub Button1_Click ( ByVal sender As System. Object, ByVal and As System.EventArgs) Handles Button1.Click
LabelResult.Text = Decrypt (TextBoxEncriptado.Text, False) End Sub Ready!
