Key Vault with the use of VBScript/Classic ASP

I have seen two instances recently where customers were asking about using VBScript/Classic ASP with Key Vault.  Key Vault does not have a library written for VBScript - it's a very old language and its use is not typical these days.  That said, there's always someone who needs to update a perfectly well-working application with some modern updates.

The great thing about Web APIs these days is that we've standardized on REST.  If you're reading this, you probably know what it is and I'm not going to get into it - you can read the Wikipedia article for more information.

That said, with every Key Vault action available as part of the REST API, we can consume Key Vault from every language that can perform HTTP requests.  I want to give a sample of VBScript retrieving a secret from Key Vault.  This code should work with very few modifications in Classic ASP as well.


 

Note: I've made use of an open-source ASP library called ASPJSON.  This is to simplify getting values from the returned JSON objects from Key Vault.  

' Written by Matthew Small on http://AzIdentity.AzureWebsites.net
' 12/15/2020

Option Explicit
dim xmlhttp, url, oJSON, accessToken, authUrl, kvUrl, clientId, clientSecret, secretValue
set xmlhttp = CreateObject("Microsoft.XMLHTTP")
set oJSON = New aspJSON

' Set constants
authUrl = "https://login.microsoftonline.com/<your tenant here>/oauth2/token"
kvUrl = "https://<your kv here>.vault.azure.net/secrets/<secret name>?api-version=7.1"
clientId = <removed>
clientSecret = <removed>


' Obtain an access token using the Microsoft OAUTH services.  I need a registered application with a client secret to make this happen.
xmlhttp.open "POST", authUrl, false
xmlhttp.setRequestHeader "Accept", "application/json"
xmlhttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
xmlhttp.setRequestHeader "Host", "login.microsoftonline.com"
xmlhttp.send "resource=https%3a%2f%2fvault.azure.net&client_id=" & clientId & "&client_secret=" & clientSecret  & "&grant_type=client_credentials"


' Use the aspJSON class to get the access token from the response
oJSON.loadJSON(xmlhttp.responseText)
accessToken = oJSON.data("access_token")

' Using the access token, call into the Key Vault to get the value of a secret.
xmlhttp.open "GET", kvUrl, false
xmlhttp.setRequestHeader "Authorization", "Bearer " & accessToken
xmlhttp.send

' Use the aspJSON class to get the secret value from the response and display it.
oJSON.loadJSON(xmlhttp.responseText)
secretValue = oJSON.data("value")
WScript.echo "The value of the secret from Key Vault is: """ & secretValue & """."


' This is the aspJSON class obtained from GITHUB at https://github.com/gerritvankuipers/aspjson.  I modifed it slightly (Server.CreateObject -> CreateObject) for use in VBS.
Class aspJSON
	Public data
	Private p_JSONstring
	private aj_in_string, aj_in_escape, aj_i_tmp, aj_char_tmp, aj_s_tmp, aj_line_tmp, aj_line, aj_lines, aj_currentlevel, aj_currentkey, aj_currentvalue, aj_newlabel, aj_XmlHttp, aj_RegExp, aj_colonfound

	Private Sub Class_Initialize()
		Set data = Collection()

	    Set aj_RegExp = new regexp
	    aj_RegExp.Pattern = "\s{0,}(\S{1}[\s,\S]*\S{1})\s{0,}"
	    aj_RegExp.Global = False
	    aj_RegExp.IgnoreCase = True
	    aj_RegExp.Multiline = True
	End Sub

	Private Sub Class_Terminate()
		Set data = Nothing
	    Set aj_RegExp = Nothing
	End Sub

	Public Sub loadJSON(inputsource)
		inputsource = aj_MultilineTrim(inputsource)
		If Len(inputsource) = 0 Then Err.Raise 1, "loadJSON Error", "No data to load."
		
		select case Left(inputsource, 1)
			case "{", "["
			case else
				Set aj_XmlHttp = CreateObject("Msxml2.ServerXMLHTTP")
				aj_XmlHttp.open "GET", inputsource, False
				aj_XmlHttp.setRequestHeader "Content-Type", "text/json"
				aj_XmlHttp.setRequestHeader "CharSet", "UTF-8"
				aj_XmlHttp.Send
				inputsource = aj_XmlHttp.responseText
				set aj_XmlHttp = Nothing
		end select

		p_JSONstring = CleanUpJSONstring(inputsource)
		aj_lines = Split(p_JSONstring, Chr(13) & Chr(10))

		Dim level(99)
		aj_currentlevel = 1
		Set level(aj_currentlevel) = data
		For Each aj_line In aj_lines
			aj_currentkey = ""
			aj_currentvalue = ""
			If Instr(aj_line, ":") > 0 Then
				aj_in_string = False
				aj_in_escape = False
				aj_colonfound = False
				For aj_i_tmp = 1 To Len(aj_line)
					If aj_in_escape Then
						aj_in_escape = False
					Else
						Select Case Mid(aj_line, aj_i_tmp, 1)
							Case """"
								aj_in_string = Not aj_in_string
							Case ":"
								If Not aj_in_escape And Not aj_in_string Then
									aj_currentkey = Left(aj_line, aj_i_tmp - 1)
									aj_currentvalue = Mid(aj_line, aj_i_tmp + 1)
									aj_colonfound = True
									Exit For
								End If
							Case "\"
								aj_in_escape = True
						End Select
					End If
				Next
				if aj_colonfound then
					aj_currentkey = aj_Strip(aj_JSONDecode(aj_currentkey), """")
					If Not level(aj_currentlevel).exists(aj_currentkey) Then level(aj_currentlevel).Add aj_currentkey, ""
				end if
			End If
			If right(aj_line,1) = "{" Or right(aj_line,1) = "[" Then
				If Len(aj_currentkey) = 0 Then aj_currentkey = level(aj_currentlevel).Count
				Set level(aj_currentlevel).Item(aj_currentkey) = Collection()
				Set level(aj_currentlevel + 1) = level(aj_currentlevel).Item(aj_currentkey)
				aj_currentlevel = aj_currentlevel + 1
				aj_currentkey = ""
			ElseIf right(aj_line,1) = "}" Or right(aj_line,1) = "]" or right(aj_line,2) = "}," Or right(aj_line,2) = "]," Then
				aj_currentlevel = aj_currentlevel - 1
			ElseIf Len(Trim(aj_line)) > 0 Then
				if Len(aj_currentvalue) = 0 Then aj_currentvalue = aj_line
				aj_currentvalue = getJSONValue(aj_currentvalue)

				If Len(aj_currentkey) = 0 Then aj_currentkey = level(aj_currentlevel).Count
				level(aj_currentlevel).Item(aj_currentkey) = aj_currentvalue
			End If
		Next
	End Sub

	Public Function Collection()
		set Collection = CreateObject("Scripting.Dictionary")
	End Function

	Public Function AddToCollection(dictobj)
		if TypeName(dictobj) <> "Dictionary" then Err.Raise 1, "AddToCollection Error", "Not a collection."
		aj_newlabel = dictobj.Count
		dictobj.Add aj_newlabel, Collection()
		set AddToCollection = dictobj.item(aj_newlabel)
	end function

	Private Function CleanUpJSONstring(aj_originalstring)
		aj_originalstring = Replace(aj_originalstring, Chr(13) & Chr(10), "")
		aj_originalstring = Mid(aj_originalstring, 2, Len(aj_originalstring) - 2)
		aj_in_string = False : aj_in_escape = False : aj_s_tmp = ""
		For aj_i_tmp = 1 To Len(aj_originalstring)
			aj_char_tmp = Mid(aj_originalstring, aj_i_tmp, 1)
			If aj_in_escape Then
				aj_in_escape = False
				aj_s_tmp = aj_s_tmp & aj_char_tmp
			Else
				Select Case aj_char_tmp
					Case "\" : aj_s_tmp = aj_s_tmp & aj_char_tmp : aj_in_escape = True
					Case """" : aj_s_tmp = aj_s_tmp & aj_char_tmp : aj_in_string = Not aj_in_string
					Case "{", "["
						aj_s_tmp = aj_s_tmp & aj_char_tmp & aj_InlineIf(aj_in_string, "", Chr(13) & Chr(10))
					Case "}", "]"
						aj_s_tmp = aj_s_tmp & aj_InlineIf(aj_in_string, "", Chr(13) & Chr(10)) & aj_char_tmp
					Case "," : aj_s_tmp = aj_s_tmp & aj_char_tmp & aj_InlineIf(aj_in_string, "", Chr(13) & Chr(10))
					Case Else : aj_s_tmp = aj_s_tmp & aj_char_tmp
				End Select
			End If
		Next

		CleanUpJSONstring = ""
		aj_s_tmp = split(aj_s_tmp, Chr(13) & Chr(10))
		For Each aj_line_tmp In aj_s_tmp
			aj_line_tmp = replace(replace(aj_line_tmp, chr(10), ""), chr(13), "")
			CleanUpJSONstring = CleanUpJSONstring & aj_Trim(aj_line_tmp) & Chr(13) & Chr(10)
		Next
	End Function

	Private Function getJSONValue(ByVal val)
		val = Trim(val)
		If Left(val,1) = ":"  Then val = Mid(val, 2)
		If Right(val,1) = "," Then val = Left(val, Len(val) - 1)
		val = Trim(val)

		Select Case val
			Case "true"  : getJSONValue = True
			Case "false" : getJSONValue = False
			Case "null" : getJSONValue = Null
			Case Else
				If (Instr(val, """") = 0) Then
					If IsNumeric(val) Then
						getJSONValue = CDbl(val)
					Else
						getJSONValue = val
					End If
				Else
					If Left(val,1) = """" Then val = Mid(val, 2)
					If Right(val,1) = """" Then val = Left(val, Len(val) - 1)
					getJSONValue = aj_JSONDecode(Trim(val))
				End If
		End Select
	End Function

	Private JSONoutput_level
	Public Function JSONoutput()
		dim wrap_dicttype, aj_label
		JSONoutput_level = 1
		wrap_dicttype = "[]"
		For Each aj_label In data
			 If Not aj_IsInt(aj_label) Then wrap_dicttype = "{}"
		Next
		JSONoutput = Left(wrap_dicttype, 1) & Chr(13) & Chr(10) & GetDict(data) & Right(wrap_dicttype, 1)
	End Function

	Private Function GetDict(objDict)
		dim aj_item, aj_keyvals, aj_label, aj_dicttype
		For Each aj_item In objDict
			Select Case TypeName(objDict.Item(aj_item))
				Case "Dictionary"
					GetDict = GetDict & Space(JSONoutput_level * 4)
					
					aj_dicttype = "[]"
					For Each aj_label In objDict.Item(aj_item).Keys
						 If Not aj_IsInt(aj_label) Then aj_dicttype = "{}"
					Next
					If aj_IsInt(aj_item) Then
						GetDict = GetDict & (Left(aj_dicttype,1) & Chr(13) & Chr(10))
					Else
						GetDict = GetDict & ("""" & aj_JSONEncode(aj_item) & """" & ": " & Left(aj_dicttype,1) & Chr(13) & Chr(10))
					End If
					JSONoutput_level = JSONoutput_level + 1
					
					aj_keyvals = objDict.Keys
					GetDict = GetDict & (GetSubDict(objDict.Item(aj_item)) & Space(JSONoutput_level * 4) & Right(aj_dicttype,1) & aj_InlineIf(aj_item = aj_keyvals(objDict.Count - 1),"" , ",") & Chr(13) & Chr(10))
				Case Else
					aj_keyvals =  objDict.Keys
					GetDict = GetDict & (Space(JSONoutput_level * 4) & aj_InlineIf(aj_IsInt(aj_item), "", """" & aj_JSONEncode(aj_item) & """: ") & WriteValue(objDict.Item(aj_item)) & aj_InlineIf(aj_item = aj_keyvals(objDict.Count - 1),"" , ",") & Chr(13) & Chr(10))
			End Select
		Next
	End Function

	Private Function aj_IsInt(val)
		aj_IsInt = (TypeName(val) = "Integer" Or TypeName(val) = "Long")
	End Function

	Private Function GetSubDict(objSubDict)
		GetSubDict = GetDict(objSubDict)
		JSONoutput_level= JSONoutput_level -1
	End Function

	Private Function WriteValue(ByVal val)
		Select Case TypeName(val)
			Case "Double", "Integer", "Long": WriteValue = replace(val, ",", ".")
			Case "Null"						: WriteValue = "null"
			Case "Boolean"					: WriteValue = aj_InlineIf(val, "true", "false")
			Case Else						: WriteValue = """" & aj_JSONEncode(val) & """"
		End Select
	End Function

	Private Function aj_JSONEncode(ByVal val)
		val = Replace(val, "\", "\\")
		val = Replace(val, """", "\""")
		'val = Replace(val, "/", "\/")
		val = Replace(val, Chr(8), "\b")
		val = Replace(val, Chr(12), "\f")
		val = Replace(val, Chr(10), "\n")
		val = Replace(val, Chr(13), "\r")
		val = Replace(val, Chr(9), "\t")
		aj_JSONEncode = Trim(val)
	End Function

	Private Function aj_JSONDecode(ByVal val)
		val = Replace(val, "\""", """")
		val = Replace(val, "\\", "\")
		val = Replace(val, "\/", "/")
		val = Replace(val, "\b", Chr(8))
		val = Replace(val, "\f", Chr(12))
		val = Replace(val, "\n", Chr(10))
		val = Replace(val, "\r", Chr(13))
		val = Replace(val, "\t", Chr(9))
		aj_JSONDecode = Trim(val)
	End Function

	Private Function aj_InlineIf(condition, returntrue, returnfalse)
		If condition Then aj_InlineIf = returntrue Else aj_InlineIf = returnfalse
	End Function

	Private Function aj_Strip(ByVal val, stripper)
		If Left(val, 1) = stripper Then val = Mid(val, 2)
		If Right(val, 1) = stripper Then val = Left(val, Len(val) - 1)
		aj_Strip = val
	End Function

	Private Function aj_MultilineTrim(TextData)
		aj_MultilineTrim = aj_RegExp.Replace(TextData, "$1")
	End Function

	private function aj_Trim(val)
		aj_Trim = Trim(val)
		Do While Left(aj_Trim, 1) = Chr(9) : aj_Trim = Mid(aj_Trim, 2) : Loop
		Do While Right(aj_Trim, 1) = Chr(9) : aj_Trim = Left(aj_Trim, Len(aj_Trim) - 1) : Loop
		aj_Trim = Trim(aj_Trim)
	end function
End Class

 

Add comment