Question

Does ASP Classic have a feature that is the equivalent of PHP’s “include once” feature?

Answer 1

I know this is an old topic, but I thought I’d add my two cents in case anyone’s interested.

I wrote a function that does precisely what you want: includes the given file exactly one no matter how many times it was called.

class ImportFunction
    private libraries_
    private fso_

    private sub CLASS_INITIALIZE
        set libraries_ = Server.createObject("Scripting.Dictionary")
        set fso_ = Server.createObject("Scripting.FileSystemObject")
    end sub

    public default property get func (path)
        if not libraries_.exists(path) then

            on error resume next
            with fso_.openTextFile(path)
                executeGlobal .readAll
                if Err.number <> 0 then 
                    Response.write "Error importing library "
                    Response.write path & "<br>"
                    Response.write Err.source & ": " & Err.description
                end if
            end with
            on error goto 0

            libraries_.add path, null
        end if
    end property
end class
dim import: set import = new ImportFunction

Notes:

• This uses a faux function simulated with a default property. If this bothers you, it’s easily refactored.

• The dictionary must be persistent through all includes, whereas persisting the fso merely avoids reconstructing it. If you don’t like the idea of keeping them around after the imports are done, you could modify the class to get syntax like this:

  with new Importer
      .import "foo"
      .import "bar/baz"
  end with