Tap this automated method for using a script to drop “unsubscribe” customers from your email lists.
Yanking Data from an Active Server Page
Tap this automated method for using a script to drop “unsubscribe” customers from your email lists.
- By Chris Brooke
- January 01, 2000
Hmm… something’s different. There’s a new column title,
a new picture (but the same goofy mug). Perhaps you’re
wondering where this month’s featured Windows utility
is. “What’s this ‘Scripting for MCSEs’ stuff?” Well… as
Kevin Costner’s manager in Bull Durham said, “The
league’s decided to make a change.” Besides, when the
editor-in-chief herself calls with an idea for a new direction
for your column, you either get on board or you get traded
to Visalia as the new bat boy. Fortunately for me (and
Visalia), I’m very excited about this new column. Yep!
We’re going to the Show. The Major Leagues. The World
Series of Scripting! The… but I digress.
The good news is we’ll still be showing you ways
to simplify your collective administrative lives. The
better news is that we’ll be focusing on more powerful
solutions made possible via Windows NT’s (and Windows
2000’s) enhanced scripting abilities. We’re going to look
at scripting from a challenge/solution perspective. Solutions
will run the gamut from simple scripts that leverage third-party
utilities and components, to complex “code-o-ramas” guaranteed
to make even the most GUI-dependent server jockey feel
like a born-again code monkey!
We’ll start by looking at some of the tools we’re going
to use on this adventure, then writing a script or two.
Nothing like jumping in with both feet!
WScript.exe / CScript.exe
These are the scripting hosts. By default they have engines
for VBScript and JScript, but you can add more if necessary.
The examples you’ll see in these pages will be VBScript
(though I may occasionally throw in some JScript—just
to keep you on your toes).
Notepad.exe
The quintessence of script editors! Notepad is where
we create our magic. Feel free to use another environment
if you want, but you can’t beat Notepad. It has no syntax
checking, no spell checking, and it doesn’t even have
Replace functionality. Not to mention the fact that it
tries to save everything with the .TXT extension. So why
do I use it? It’s a bad habit I can’t seem to break.
VBS file extension
If we manually start each script using either WScript
or CScript, we can give the script files any extension,
so long as we have that extension associated with a script
engine. However, the WSH registers the .VBS and .JS extensions
as VBScript and JScript, respectively. If we use these
extensions, we can execute the scripts simply by double-clicking
on the file. Remember not to do this if your script is
expecting command-line arguments, or you’ll get an error.
Active Server Pages
No, this isn’t going to be a column on Web site development.
Nevertheless, there are times when our administrative
tasks may require the services of an Internet/intranet
server. Indeed, this month’s script is a perfect example.
When we find our administrative tasks crossing paths with
our Web servers, the scripts will include the relevant
ASP code.
In this column (stay with me), we’re going to write a
script to create and add to a text file. While this seems
simple enough on the surface, there are a few hurdles
to leap when attempting to automate it inside a script.
Let’s look at a common scenario…
The Situation
Your company sends regular email updates to your customer
base, informing them of the latest product/service/doohickey
that you offer. Even though these are registered customers,
you must provide a way for them to be removed from your
mailing list lest ye be accused of spamming. Short of
purchasing an expensive electronic mail system that does
this automatically, you need to find a way to keep track
of these “removes” so that you no longer mail to them.
Your emailing program uses a text file containing email
addresses to handle delivery. It also uses tags that can
reference any data you want in the message itself (usually
this is used for names, but you’ve decided to embed the
Contact ID instead). This file has already been properly
formatted.
You write your email and add the link at the end for
the customer to click if he or she wishes to be removed.
The link looks something like this:
http://www.mycompany.com/email/remove.asp?
The email software replaces the tag with
the text you specified when it delivers the message. In
this case, the text is:
[email protected]
When the customer receives the email, the link is complete:
http://www.mycompany.com/email/[email protected]
Our challenge lies in telling the Active Server Page
to add the Contact ID and email address for each “remove”
into a comma-delimited file. (We already have software
to parse that file and remove each person from the email
database.) In order to make this happen, we need to use
the Windows component “Scripting.FileSystemObject” and
the ASP component “Request.QueryString.”
Request.QueryString returns the data associated with
a label that is passed to the Active Server Page—in other
words, everything that comes after the “?” on the URL.
The labels in this case are “CID” and “Email”. To accomplish
this, we add the code in Listing 1 anywhere inside the
file “remove.asp”.
| Listing 1. This is the code
that you insert into the file "remove.asp". |
< ' this="" tells="" iis="" that="" the="" script="" starts="">
Const ForAppending=8
' The VBScript code to append to the open file
Set objFSO=Server.CreateObject
(“Scripting.FileSystemObject”
' The "True" flag in the next line tells
IIS to
' create the file if it doesn't already exist
Set objFile=objFSO.OpenTextFile(“c:\removes\remove.txt”,
ForAppending, True)
' Get the data from the ASP query string and format
it,
' separating the fields with a comma
strLine=Request.QueryString(“CID”) & ","
& Request.QueryString(“Email”)
ObjFile.WriteLine strLine ' Write the line
ObjFile.Close
' Close the file
' Exit the script
%>
|
Every time a user clicks the “remove” link, it adds the
user name and contact ID to the file “remove.txt,” which
is used to handle that actual removal from the database.
(There are more complex ways of doing this directly, but
for now let’s keep it simple.)
As we go along each month, I’ll explain the rules and
conventions I use when writing scripts. Some are required
and some are simply the “standard.”
Variable Names
I always precede each variable with an indication of
its type:
- obj—Object
- str—String
- b—Boolean (yes/no or True/False)
- i—Integer
I’ll cover other variable types as we encounter them.
Objects
All objects (objObjectName) are created with “Set” and
“CreateObject” (or Server.CreateObject with ASP). The
exception to this is when a method of one object returns
another object, as in line 5 of our script. The OpenTextFile
method of the FileSystemObject returns a TextStream object.
Dealing with objects is one of the more difficult concepts
when scripting. I’ll do my best to explain the rules as
we go and thus avoid any unnecessary headaches.
Scripting is powerful. It’s also a lot of fun. Batter
up!
About the Author
Chris Brooke, MCSE, is a contributing editor for Redmond magazine and director of enterprise technology for ComponentSource. He specializes in development, integration services and network/Internet administration. Send questions or your favorite scripts to [email protected].