Simple HttpResponse in ASPX VB - asp.net

Question

We have an old Asp.net 2.0 web service where I need to put in a simple HTTP response. In the below code, the function "APIValidation()" returns an int, 200 or 404. All I need to do is have it send an HttpResponse so my node web app can read the statuscode (and then do what it needs to do).
I have no idea how to do this (I'm a noob with ASP), the tutorials I find are too elaborate, it seems this could be solved in a few lines of code, I just don't know which.
You can see it in action here:
200 : http://registration.imprintplus.com/imprinttest/GlobalSrvSN.aspx?sn=29820C0792024CDC8D590BF14AF42490
404: http://registration.imprintplus.com/imprinttest/GlobalSrvSN.aspx?sn=invalid
The other option is for Node to be able to extract the 200 or 404 out of what the ASP service gives me. Either or works for me.
Option Explicit Off
Option Strict Off
Imports ActivationServer
Partial Class GlobalSrvSN
Inherits System.Web.UI.Page
Public Function APIValidation(ByVal sn As String, ByVal databaseSource As String) As String
Dim act As New LogicProtect_ActivationServer(databaseSource)
Return act.APIValidation("user", "user#company.com", sn)
End Function
End Class
thanks a million!

Answer 1

Unsure how you're calling that function so will assume a few things if that's the only code you have.
If you're calling it from the .aspx file then this would be an example:
<%# Page Language="vb" ....." %>
<%
Dim foo = APIValidation(Request("sn"), "other string")
Response.StatusCode = CInt(foo)
%>
If from "code behind" ([page].aspx.vb):
Option Explicit Off
Option Strict Off
Imports ActivationServer
Partial Class GlobalSrvSN
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim foo = APIValidation(Request("sn"), "other string")
Response.StatusCode = CInt(foo)
End Sub
Public Function APIValidation(ByVal sn As String, ByVal databaseSource As String) As String
Dim act As New LogicProtect_ActivationServer(databaseSource)
Return act.APIValidation("user", "user#company.com", sn)
End Function
End Class
Notes: Above is a very trivial answer to keep things simple. But:
above is really a "Web Forms Page" (not technically a "web service") which would be asmx (2.0)
Skipped any input validation (queryString), error checking/handling.
Response object is how you'd control HTTP Responses (headers, etc.)
Hth