I reviewed some recent client Classic ASP code and found a 4 level deep branching of an IF statement. Reading the code, its intent is to look at the object type and return an icon representing the type.

   <% 
    if  obj.type = "car" then
            response.write("<img src="/images/icons/car.png" />")
    ElseIf obj.type = "boat" then
	    response.write("<img src="/images/icons/boat.png" />")
    ElseIf obj.type = "bike" then
	    response.write("<img src="/images/icons/bike.png" />")
    Else
	    response.write("<img src="/images/icons/placeholder.png" />")
   %>

I try to stay away from IF statements altogether but using a SINGLE if statement is something I do use. However, once the IF statement gets past 2 branches, I consider this a CODE SMELL it requires refactoring.

I am going to break my thoughts into small code refactorings so you can understand each step. each step in itself is an improvement to the code, but combined, it will help make changes for the client easier and less prone to bugs.

Step 1

Taking a look at the above code, I notice we are repeating the IMAGE SRC path. So let’s see if we can make better.

   <% 
    Dim imgSrc
    imgSrc = "/images/icons/"

    if  obj.type = "car" then
            response.write("<img src='" & imgSrc & "car.png" />")
    ElseIf obj.type = "boat" then
	    response.write("<img src='" & imgSrc & "boat.png" />")
    ElseIf obj.type = "bike" then
	    response.write("<img src='" & imgSrc & "bike.png" />")
    Else
	    response.write("<img src='" & imgSrc & "placeholder.png" />")
   %>

Step 2

Now, we are still repeating the response.write(" block several times. Let’s refactor the IF statement to only have logic about the obj.type.

   <% 
     Dim imgSrc, img
     imgSrc = "/images/icons/"

     img = "placeholder.png"
     if  obj.type = "car" then img = "car.png"
     if  obj.type = "boat" then img = "boat.png"
     if  obj.type = "bike" then img = "bike.png"

     response.write("<img src='" & imgSrc & img & "'" />")


   %>

Refactoring Results

The code is much easier to read and to maintain. We can easily add more branches without thinking of the rest of the logic. A non-programmer can look at this code and figure out how to add more images or even change the root path to the images.

In the next post, we will extract the IF statements into a Classic ASP Function.

If you are a looking for Classic ASP Experts or upgrading to .NET from Classic ASP , give us a call.

I the last blog post Converting Recordset into Objects in Classic ASP we created a public function initialize(rs) which takes in a single row from the database and creates a single class object account.  Our goal is to add a new property named fullname where we combine firstname and lastname

We will update the public function initialize(rs) as follows:

public function initialize(rs)

dim row
set row = New account

   row.id = rs("id")
   row.guid = rs("guid")
   row.lastName = rs("lastName")
   row.firstName = rs("firstName")
   row.fullname = rs("firstName") & ", " & rs("firstName") 
   row.email = rs("email")
   row.password = rs("password")
   row.passwordSalt = rs("passwordSalt")
   row.clientId = rs("clientId")
   row.administrator = rs("administrator")
   row.lastLogin = rs("lastLogin")
   row.created = rs("created")
   row.modified = rs("modified")
   row.active = rs("active")

set initialize = row

end function

Updated the UL code with a new LI item for fullname.

<%
Dim rsAccount
set rsAccount = getall()
%>

<ul>

<%
  While (NOT rsAccount.EOF)

  Dim account
  call account = initialize(rsAccount)

 %>
 
   <li><%=account.id%></li>
   <li><%=account.guid%></li>
   <li><%=account.lastname%></li>
   <li><%=account.firstname%></li>
   <li><%=account.fullname%></li>
   <li><%=account.email%></li>
   <li><%=account.password%></li>
   <li><%=account.passwordSalt%></li>
   <li><%=account.clientId%></li>
   <li><%=account.administrator%></li>
   <li><%=account.lastLogin%></li>
   <li><%=account.created%></li>
   <li><%=account.modified%></li>
   <li><%=account.active%></li>
 
 <% 
  rsAccount.MoveNext()
  Wend
 %>

</ul>

If you run the code as is, you will get an error Variable is undefined: 'fullname'

All we need to do is make sure the account Class a property defined for fullname.

Class account

  public id
  public guid
  public lastName
  public firstName
  public fullname 
  public email
  public password
  public passwordSalt
  public clientId
  public administrator
  public lastLogin
  public created
  public modified
  public active

End Class

Now your code should run without an error. You now have an account object with a property fullname.

If you are a looking for Classic ASP Experts or upgrading to .NET from Classic ASP , give us a call.

Now that you know how to create a Class and Objects in Classic ASP, we will look at Converting Recordset into Objects in Classic ASP.

Lets create a Class account which has several properties. I usually use the database table account and copy the model so the Class matches the database model

Class account

  public id
  public guid
  public lastName
  public firstName
  public email
  public password
  public passwordSalt
  public clientId
  public administrator
  public lastLogin
  public created
  public modified
  public active

End Class

Here I am creating a getall function to return all the rows in the account table in the database.

public function getall()

   dim sql
   sql = "select * from account"

   dim rs
   set rs = conn.execute(sql)
   set getall = rs

end function

When I started with Classic ASP, I would have written a simple While Loop

<%
Dim rsAccount
set rsAccount = getall()
%>

<ul>

<%
  While (NOT rsAccount.EOF)
 %>
 
   <li><%=rsAccount("id")%></li>
   <li><%=rsAccount("guid")%></li>
   <li><%=rsAccount("lastname")%></li>
   <li><%=rsAccount("firstname")%></li>
   <li><%=rsAccount("email")%></li>
   <li><%=rsAccount("password")%></li>
   <li><%=rsAccount("passwordSalt")%></li>
   <li><%=rsAccount("clientId")%></li>
   <li><%=rsAccount("administrator")%></li>
   <li><%=rsAccount("lastLogin")%></li>
   <li><%=rsAccount("created")%></li>
   <li><%=rsAccount("modified")%></li>
   <li><%=rsAccount("active")%></li>
 
 <% 
  rsAccount.MoveNext()
  Wend
 %>

</ul>

The above code would write to the screen a <UL> foreach account row and <LI> foreach field/record in the database.

Object-Oriented Programming Approach

An OOP [Object-Oriented Programming] approach would be to initialize each account record using the account Class.

Instead of getting each data element using Recordset rsAccount("lastName"), we will use another function to map the Recordset row into our account object.

The public function initialize(rs) takes in a single row from the database and creates a single class object account.

public function initialize(rs)

dim row
set row = New account

   row.id = rs("id")
   row.guid = rs("guid")
   row.lastname = rs("lastname")
   row.firstname = rs("firstname")
   row.email = rs("email")
   row.password = rs("password")
   row.passwordSalt = rs("passwordSalt")
   row.clientId = rs("clientId")
   row.administrator = rs("administrator")
   row.lastLogin = rs("lastLogin")
   row.created = rs("created")
   row.modified = rs("modified")
   row.active = rs("active")

set initialize = row

end function

Updated code combining Recordset with Class and Initializing each row into an object.

<%
Dim rsAccount
set rsAccount = getall()
%>

<ul>

<%
  While (NOT rsAccount.EOF)

  Dim account
  set account = initialize(rsAccount)

 %>
 
   <li><%=account.id%></li>
   <li><%=account.guid%></li>
   <li><%=account.lastname%></li>
   <li><%=account.firstname%></li>
   <li><%=account.email%></li>
   <li><%=account.password%></li>
   <li><%=account.passwordSalt%></li>
   <li><%=account.clientId%></li>
   <li><%=account.administrator%></li>
   <li><%=account.lastLogin%></li>
   <li><%=account.created%></li>
   <li><%=account.modified%></li>
   <li><%=account.active%></li>
 
 <% 
  rsAccount.MoveNext()
  Wend
 %>

</ul>

If you are a looking for Classic ASP Experts or upgrading to .NET from Classic ASP , give us a call.