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Server Side Scripting

Visual Basic Script and HTML code are combined in the same document having an SSC extension. We proudly call this PIASe scripting. To indicate server-side script you must use the <% and %> script block tag's. To indicate the insertion of a result from a PIASe expression into the HTML you must use the <%= and %> insertion tag's. When you start writing script you always begin with an block / insertion start tag (<% or <%=) and you end the script with an block / insertion end tag (%>).

A simple example:

<%
    Text = "Hello world"
%>
<html>
<head>
<title><%= Text %></title>
</head>
<body>
<p><%= Text %></p>
</body>
</html>

The script that's inside the script-tags will be evaluated at server-side and is never visible to the client. The blue marked HTML and the result of the two insertion tag's will be sent to the client. In the first tag the variable Text is assigned with the text "Hello world". The content of the variable is then inserted as the title of the document (second tag) and finally inserted as part of the body (third tag).

The client would see this as the source of the received document:

<html>
<head>
<title>Hello world</title>
</head>
<body>
<p>Hello world</p>
</body>
</html>

PIASe

PI (The initial name of the server CORE project) Active Script engine. This engine translates your server side script into code blocks that can be processed by Visual Basic Scripting. If you have CORE hands-on we'll assure you that PIASe is where you need to be to program a standard HTTP server just the way you want.

And indeed, It looks like ASP but it is not. In fact, it's Visual Basic Scripting for Windows, a VB6 preprocessor and a VB6 function library hooked together and named PIASe. No matter what level you're coding in, as long as it is VB you will have the ability to understand and change not only server side scripts but also the server itself!

PIASe script before preprocessing...

<html>
<head>
<title>Conditional building</title>
</head>
<body>
<p>A If/Then:</p>
<%
  SomeVal = 1234
  Test = 2
  If Test = 1 Then
%>
<p>Block one <%= SomeVal %></p>
<%
  ElseIf Test = 2 Then
%>
<p>Block two <%= SomeVal %></p>
<%
  Else
%>
<p>Block three <%= SomeVal %></p>
<%
  End If
%>
<p>A For/Next:</p>
<%
  For N = 1 to 10
    If N > 4 Then
%>
<p>N = <%= N %></p>
<%
    End If
  Next
%>
</body>
</html>

And after preprocessing...

'#PIASe: 1.0
'#dep: C:\SourceForge GNU OpenSource\DS\www\Page01.ssc; 19-12-2005 1:38:53
Dim Index
Sub Main( PrePrepIndex )
Index = PrePrepIndex
Out Index, "<html> " & vbCrLf '#inf:1 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<head> " & vbCrLf '#inf:2 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<title>Conditional building</title> " & vbCrLf '#inf:3 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "</head> " & vbCrLf '#inf:4 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<body> " & vbCrLf '#inf:5 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>A If/Then:</p> " & vbCrLf '#inf:6 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:7 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
SomeVal = 1234 '#inf:8 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Test = 2 '#inf:9 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
If Test = 1 Then '#inf:10 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:11 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>Block one "
Out Index, SomeVal
Out Index, "</p> " & vbCrLf '#inf:12 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:13 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
ElseIf Test = 2 Then '#inf:14 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:15 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>Block two "
Out Index, SomeVal
Out Index, "</p> " & vbCrLf '#inf:16 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:17 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Else '#inf:18 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:19 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>Block three "
Out Index, SomeVal
Out Index, "</p> " & vbCrLf '#inf:20 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:21 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
End If '#inf:22 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:23 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>A For/Next:</p> " & vbCrLf '#inf:24 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:25 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
For N = 1 To 10 '#inf:26 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
If N > 4 Then '#inf:27 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:28 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "<p>N = "
Out Index, N
Out Index, "</p> " & vbCrLf '#inf:29 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
'#inf:30 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
End If '#inf:31 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Next '#inf:32 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:33 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "</body> " & vbCrLf '#inf:34 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, "</html> " & vbCrLf '#inf:35 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, " " & vbCrLf '#inf:36 C:\SourceForge GNU OpenSource\DS\www\Page01.ssc
Out Index, ""
End Sub 

The Visual Basic script above will be cached and can now be executed to produce the server output by calling server class module functions. Note that this conversion is not visible to the script programmer.

Below, The actual VB6 code fragment of the CORE procedure WWWRequest that is responsible for running the preprocessed Visual basic scripts.


  iLoopCounter = 0
 
  Do While ttsWSconnection(Index).RunScript <> ""
 
    iLoopCounter = iLoopCounter + 1
   
    frmHomeWebmaster.PSC(Index).Reset
    frmHomeWebmaster.PSC(Index).AddObject "PiWS", clsPWwebserver, True
    frmHomeWebmaster.PSC(Index).AddObject "PiUDP", clsPWUdpLib, True
    frmHomeWebmaster.PSC(Index).AddObject "PiFW", clsPWfirewall, True
    frmHomeWebmaster.PSC(Index).AddObject "PiFIO", clsPWfileio, True
    frmHomeWebmaster.PSC(Index).AddObject "PiBase64", clsPWBase64, True
    frmHomeWebmaster.PSC(Index).AddObject "PiURLenc", clsURLenc, True
    frmHomeWebmaster.PSC(Index).AddObject "PiDateTime", _
                           clsPWdatetime, True
    frmHomeWebmaster.PSC(Index).AddObject "PiSession", _
                            clsPWsession, True
    frmHomeWebmaster.PSC(Index).AddObject "PiCommon", _
                             clsPWcommon, True
    frmHomeWebmaster.PSC(Index).AddObject "PiGlobal", _
                            clsGlobalMem, True
    frmHomeWebmaster.PSC(Index).AddObject "PiEncryption", _
                           clsEncryption, True
    frmHomeWebmaster.PSC(Index).AddObject "PiUsers", _
                              clsPWusers, True
    frmHomeWebmaster.PSC(Index).AddObject "PiHttpProxy", _
                          clsPwHttpProxy, True
    frmHomeWebmaster.PSC(Index).AddObject "PiIcmp", _
                                          clsPwIcmp, True
    frmHomeWebmaster.PSC(Index).AddObject "PiCustom", clsPwIcmp, True
    frmHomeWebmaster.PSC(Index).AddObject "PiHex", clsHex, True
     
    sScriptFile = ttsWSconnection(Index).RunScript
   
    ttsWSconnection(Index).RunScript = ""
           
    clsPWfileio.LoadFile _
      sScriptCode, _
      tssProgInfo.PiRoot & sScriptFile, _
      lLoadScriptError, _
      True
  
    If left(sScriptCode, 5) = "<sfw>" Then
      sScriptCode = EncSfwFile(tssProgInfo.PiRoot & _
                               sScriptFile, sScriptCode)
     
    End If
    
    sScriptCode = PrePrep(Index, tssProgInfo.PiRoot & sScriptFile, _
                          sScriptCode, bIsPrepped, PrepErr, _
                          sPrepErrMsg)
   
    If PrepErr <> 0 Then
      Error PrepErr
    End If
   
    If bIsPrepped Then
      clsPWfileio.SetCache _
        clsPWfileio.InFileCache(tssProgInfo.PiRoot & sScriptFile), _
        tssProgInfo.PiRoot & sScriptFile, _
        sScriptCode, _
        True
    End If
   
    If lLoadScriptError = 0 Then
      frmHomeWebmaster.PSC(Index).AddCode sScriptCode
    End If
   
    frmHomeWebmaster.PSC(Index).Run "Main", Index
   
    If sScriptFile = ttsWSconnection(Index).RunScript Then 
      'Script recursion
      Error 5
      Exit Do                                               
    End If
 
    If iLoopCounter > 16 Then
      Error 5
      Exit Do
    End If
   
  Loop
   

PIASe, VBS, VB6... This is our VB6 solution to create a server that is able to run dynamically and interatively server side scripts. It's up to you to make good use of the service.

Do you want to join and help us with the PIASe project to improve it? Write us a note.

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