ASP CAPTCHA: LanapBotDetectHandler.asp

Este script ASP es utilizado por BotDetect ASP CAPTCHA para procesar las peticiones de imagen y audio del CAPTCHA generado por BotDetect CAPTCHA. Puede ser utilizado fácilmente como puede apreciarse en la siguiente página sobre añadir la protección CAPTCHA a sus formularios en ASP.

Por defecto, este archivo se encuentra instalado en la carpeta
C:\Archivos de programa\Lanapsoft\BotDetect\ASP\v2.0\Modules\

Código fuente completo del archivo

<%
Dim code, codeKey, codeHash, codeHashKey, captchaId, comCaptcha, _ 
  index, appCodeKey, captchaSessionIdKey

'the Captcha code is kept in Session state with this key
codeKey = "LanapBotDetectCode"
codeHashKey = "LanapBotDetectCodeHash"
captchaSessionIdKey = "LanapBotDetectID"

Function createGuid()
  Set TypeLib = Server.CreateObject("Scriptlet.TypeLib")
  tg = TypeLib.Guid
  guid = Left(tg, len(tg)-2)
  set regEx = New RegExp
  regEx.IgnoreCase = False
  regEx.Global = True
  regEx.Pattern = "[{}-]"
  createGuid = regEx.Replace(guid, "")
  Set TypeLib = Nothing
End Function

Function getCaptchaSessionID()
  Dim captchaSessionID
  If (Session(captchaSessionIdKey) <> "") Then
    captchaSessionID = Session(captchaSessionIdKey)
  Else
    captchaSessionID = createGuid()
    Session(captchaSessionIdKey) = captchaSessionID
  End If
  getCaptchaSessionID = captchaSessionID
End Function

'if there are multiple Captchas on tn the site, a Captcha id is 
'required to distinguish between them; otherwise, it can be ignored
captchaId = Request("CaptchaId")
If(captchaId<>"") Then
  codeKey = codeKey & "_" & captchaId
End If

If (Request("Command")="CreateImage") Then
'Captcha image generation

  'create the Captcha component instance
  Set comCaptcha = CreateObject("Lanap.BotDetect")

  'process Captcha properties
  If (Request("TextStyle")<>"") Then 'set Captcha algorithm
    On Error Resume Next
    comCaptcha.TextStyle = CLng(Request("TextStyle"))
    Err.Clear
  End If
  If (Request("ImageWidth")<>"") Then 'set Captcha image width
    On Error Resume Next
    comCaptcha.ImageWidth = CLng(Request("ImageWidth"))
    Err.Clear
  End If
  If (Request("ImageHeight")<>"") Then 'set Captcha image height
    On Error Resume Next
    comCaptcha.ImageHeight = CLng(Request("ImageHeight"))
    Err.Clear
  End If
  If (Request("CodeLength")<>"") Then 'set Captcha code length
    On Error Resume Next
    comCaptcha.CodeLength = CLng(Request("CodeLength"))
    Err.Clear
  End If
  If (Request("CodeType")<>"") Then 'set Captcha code type
    On Error Resume Next
    comCaptcha.CodeType = CLng(Request("CodeType"))
    Err.Clear
  End If
  If (Request("Format")<>"") Then 'set Captcha image format
    On Error Resume Next
    comCaptcha.Format = Request("Format")
    Err.Clear
  End If

  'set Captcha image Http response headers
  Response.Buffer = True
  Response.CacheControl = "no-cache, no-store, must-revalidate"
  Response.AddHeader "Pragma", "no-cache"
  Response.Expires = -1
  If (comCaptcha.Format="JPEG") Then
    Response.ContentType = "image/jpeg"
  ElseIf (comCaptcha.Format="PNG") Then
    Response.ContentType = "image/png"
  ElseIf (comCaptcha.Format="GIF") Then
    Response.ContentType = "image/gif"
  ElseIf (comCaptcha.Format="BMP") Then
    Response.ContentType = "image/bmp"
  End If

  'generate the Captcha image binary data
  Dim varPicture
  varPicture = comCaptcha.CreateImage

  'save the Captcha code for sound generation and validation
  code = comCaptcha.GetValue
  Session(codeKey) = code
  'save the code hash for backward compatibility with older validation 
  'code
  codeHash = comCaptcha.GetHashValue
  Session(codeHashKey) = codeHash

  'Chrome workaround
  index = InStr(Request.ServerVariables("HTTP_USER_AGENT"), "Chrome")
  If (index > 0) Then
    appCodeKey = getCaptchaSessionID() & codeKey
    Application.Lock
    Application(appCodeKey) = code
    Application.UnLock
    Response.Cookies(captchaSessionIdKey) = getCaptchaSessionID()
    Response.Cookies(captchaSessionIdKey).Expires = DateAdd("H", 1, Now)
    Response.Cookies(captchaSessionIdKey).Path = "/"
  End If

  'send Captcha image binary data to the client
  Response.BinaryWrite varPicture
  Set comCaptcha = Nothing 'dispose of the Captcha component instance
  Response.End
'end Captcha image generation

ElseIf (Request("Command")="CreateSound") Then
'audio Captcha generation

  'create the Captcha component instance
  Set comCaptcha = CreateObject("Lanap.BotDetect")

  'set Http response headers
  If ((Request.ServerVariables("HTTPS")="off") Or Request("e")="") Then
    Response.CacheControl = "no-cache"
    Response.AddHeader "Pragma", "no-cache"
    Response.Expires = -1
  End If
  Response.Buffer = True
  Response.ContentType = "audio/x-wav"
  If (Request("d") = "") Then
  Response.AddHeader "content-disposition", _
    "attachment; filename=captcha.wav"
  End If
  Response.AddHeader "Content-Transfer-Encoding", "binary"
  Response.AddHeader "Connection", "Close"

  'generate the audio Captcha binary data from the saved code
  code = Session(codeKey)
  If (Request("s") <> "") Then 'Chrome workaround
    appCodeKey = Request("s") & codeKey
    code = Application(appCodeKey)
  End If
  varSound = comCaptcha.CreateSoundFromCode(code)

  'send audio Captcha binary data to the client
  Response.BinaryWrite varSound
  Set comCaptcha = Nothing 'dispose of the Captcha component instance
  Response.End
'end audio Captcha generation

ElseIf (Request("Command")="Validate") Then
'Ajax Captcha validation

  Dim result
  result = False

  If (Session(codeKey)<>"") Then
    Dim inputCode
    inputCode = Request("Code")
    code = Session(codeKey)
    result = (0 = StrComp(inputCode, code, 1))
    'Ajax validation shouldn't remove the code if successful, so both 
    'client- and server-side validation can be performed and pass
    If (Not result) Then
      Session(codeKey) = ""
    End If
  End If

  'Http response headers
  Response.Buffer = True
  Response.ContentType = "text/javascript"
  Response.CacheControl = "no-cache, no-store, must-revalidate"
  Response.AddHeader "Pragma", "no-cache"
  Response.Expires = -1
  Response.AddHeader "Connection", "Close"

  'send the JSON validation result to the client
  Response.Write "{ 'result': " & LCase(CStr(result)) & " }"
  Response.End

'end Ajax Captcha validation
End If

'If neither of the above conditions was met
Response.Status = "400 Bad Request"
Response.End
%>