Subscribe.asp
<%@ Language=JavaScript %>

<!--#include file = "include/SetGlobals.asp"-->
<!--#include file = "include/DBPath.asp"-->

<%
// output relevant meta tags
Init( "Subscription" );

// output common top of page
Header( \'<a href="work.asp">Work</a> --> Subscription\', 3 );

// output page content
Content ( );

// output common bottom of page
Footer( );
%>

<% /* standard page elements */ %>
<!--#include file = "utils/Init.asp"-->
<!--#include file = "utils/Database.asp"-->
<!--#include file = "utils/Header.asp"-->
<!--#include file = "utils/Footer.asp"-->

<%
// ============================================
// the content of this page
// ============================================
function Content ( )
{
Out ( \'<td width="20%">&nbsp;</td>\' );
Out ( \'<td width="60%">\' );

// if the form has an email address, validate it first
// so that if it fails we can show the form to fix
var sEmail = "";
var bSubmitted = (Request.Form.Count > 0);

// has the form been submitted?
if ( bSubmitted )
{
// get the email address from the form...
sEmail = "" + Request.Form ( "email" );

// validate the email address and moan if it fails
if ( !IsValidEmail ( sEmail ) )
{
Out ( \'<h5><font color="red">"\' + sEmail + \'" <i>appears</i> to be an invalid email address - please try again!</font></h5>\' );
Out ( \'<p><font color="red">If you disagree, please <a href="Contact.asp">contact me</a> directly.</font><p>\' );
// pretend the form hasn\'t been sent yet
bSubmitted = false;
}
}

// show the form if not submitted yet
if ( !bSubmitted )
{
Out ( \'If you\'re interested in hearing whenever a new article is posted, or an existing one is updated, type in your email address below and hit <b>Subscribe!</b>\' );
Out ( \'<p>Whenever you want to stop receiving my emails, guess what? That\'s right, enter your email address and hit <b>Unsubscribe</b>...\' );
Out ( \'<p><i>Your email address will never sold to or otherwise used by any third party, just me.</i>\' );

// here\'s the form tag. the action attribute is the name of
// the file that will be called with the answer - in this case
// it\'s the same page. the method can be "post" to send the
// form data \'behind the scenes\' or "get" to appending the
// data to the URL in the style page.asp?data1=a&data2=b
//
// use post most of the time - it\'s neater and "get" is limited
// in the amount of data that can be sent.
Out ( \'<center><form action="Subscribe.asp" method="post">\' );

// another table to line up the titles and inputs
Out ( \'<table border="0" cellpadding="0">\' );
Out ( \'<tr><td align="right" valign="top">\' );
Out ( \'Email:\' );
Out ( \'</td><td align="left" valign="top">\' );
// a simple text box. we\'ll reference it with the name "name"
// and show 22 characters on the form. use the maxlength
// attribute to set the maximum characters they can enter.
// use value="some text" to pre-fill the input with data.
//
// IMPORTANT! using names that are commonly used by
// other web sites has a big advantage to the user - IE
// will drop down a list of previous answers, which they
// can usually pick from rather than type in. Think about this.
Out ( \'<input type="text" name="email" size="31" value="\' + sEmail + \'"></input>\' );
Out ( \'</td></tr>\' );

Out ( \'<tr><td align="right" valign="top">\' );
Out ( \'&nbsp;\' );
Out ( \'</td><td align="left" valign="top">\' );
// type=\'submit" provides a submit button to perform the
// form action. the button says "Submit" unless you override
// with the value attribute.
Out ( \'<input type="submit" name="action" value="Subscribe"></input>&nbsp;<input type="submit" name="action" value="Unsubscribe"></input>\' );
Out ( \'</td></tr>\' );

Out ( \'</table>\' );
Out ( \'</form></center>\' );
}
else
{
var sAction = "" + Request.Form ( "action" );

if ( sAction == "Subscribe" )
AddEmail ( sEmail ) ;
else
RemoveEmail ( sEmail );

Out ( \'<p>\' );
}

Out ( \'Do you want to see how this form adds and removes addresses to my database? All the source code is just a click away!\' );
Out ( \'<p><center><a href="ShowSource.asp? page=Subscribe"><img src="images/source.gif" border=0></a></center>\' );
Out ( \'<p>In <a href="MailToList.asp">Part 2</a> see how I wrote a form to mail all my subscribers...\' );

Out ( \'</td>\' );
Out ( \'<td width="20%">&nbsp;</td>\' );
}

// ============================================
// validate email address
// ============================================
function IsValidEmail ( sEmail )
{
// regular expression courtesy of ed.courtenay@nationwideisp.net
// I won\'t even pretend that I\'ve read through this yet!

if ( sEmail.search ( /w+((-w+)|(.w+)|(_w+))*@[A-Za-z0-9]+((.|-)[A-Za-z0- 9]+)*.[A-Za-z]{2,5}/ ) != -1 )
return true;
else
return false;
}


// ============================================
// add email to database
// ============================================
function AddEmail ( sEmail )
{
// open the connection
DBInitConnection ( );

// first see if they are already subscribed
var sSQL = \'SELECT Email FROM MailingList WHERE Email="\' + sEmail + \'";\';

DBGetRecords ( sSQL );

if ( !oRecordSet.EOF )
{
Out ( \'<h5><font color="red">\' + sEmail + \' is already subscribed to my mailing list!</font></h5>\' );
return;
}

// this section needs more work - what should be done is that an email is
// sent to the email address, and only added to the database when we
// get a reply. that way we know the address is valid and the recipient
// really wants to join the list. for now though, we\'ll add to the db now.
sSQL = \'INSERT INTO MailingList (Email) VALUES ("\' + sEmail + \'");\';

oConnection.Execute( sSQL );

// free the connection
DBReleaseConnection ( );

Out ( sEmail + \' has been successfully subscribed to my mailing list. \' );
Out ( \'<p>You will now receive an email whenever I write new articles, or if I make an important update to any.\' );

Email ( \'Joined the ShawThing mailing list\', sEmail, \'You have successfully subscribed to the mailing list at ShawThing. If you didn\'t request this please reply to this email, or visit http://www.shawthing.com/subscribe.asp to unsubscribe.nnThank you.nnJames Shawnhttp://www.shawthing.com/\' );
}


// ============================================
// remove email from database
// ============================================
function RemoveEmail ( sEmail )
{
// open the connection
DBInitConnection ( );

// first see if they are already subscribed
var sSQL = \'SELECT Email FROM MailingList WHERE Email="\' + sEmail + \'";\';

DBGetRecords ( sSQL );

if ( oRecordSet.EOF )
{
Out ( \'<h5><font color="red">\' + sEmail + \' isn\'t subscribed to my mailing list!</font></h5>\' );
return;
}

// delete from the database
sSQL = \'DELETE FROM MailingList WHERE Email="\' + sEmail + \'";\';

oConnection.Execute( sSQL );

// free the connection
DBReleaseConnection ( );

Out ( sEmail + \' has been successfully removed from my mailing list. \' );
Out ( \'<p>You have been sent a confirmation email, but after that you will not receive any more emails.\' );

Email ( \'Removal from ShawThing mailing list\', sEmail, \'You have been successfully removed from the mailing list at ShawThing. If you didn\'t request this please reply to this email, or visit http://www.shawthing.com/subscribe.asp to re-subscribe.nnThank you.nnJames Shawnhttp://www.shawthing.com/\' );
}


// ============================================
// email me!
// ============================================
function Email ( sSubject, sEmail, sMessage )
{ // send an email to the address just to confirm what just happened
var oMail = Server.CreateObject ( "CDONTS.NewMail" );

// setup the mail
oMail.From = \'DB@shawthing.com\';

oMail.To = sEmail;
oMail.Importance = 1;

oMail.Subject = sSubject;
oMail.Body = sMessage;

// send it
oMail.Send ( );

// release object
oMail = null;
}
%>

utils/Database.asp
<%
// globals
var oConnection;
var oRecordSet;
var sConnection;

// ============================================
// example usage:
// DBInitConnection ( );
//
// var sSQL = "SELECT * FROM Somewhere";
//
// DBGetRecords ( sSQL );
//
// ...use oRecordSet
//
// DBReleaseRecords ( ); // optional step
//
// DBReleaseConnection ( );
// ============================================

// ============================================
// initializes database variables for first use on page
// ============================================
function DBInitConnection ( )
{
// don\'t open it again if already opened!
if ( sConnection != undefined )
return;

// get connection object
oConnection = Server.CreateObject( \'ADODB.Connection\' );

// get the database connection string
// use MapPath to make relative path into physical path
sConnection = \'Provider=Microsoft.Jet.OLEDB.4.0; Data Source=\' + Server.MapPath ( sDBPath );

// open the connection
oConnection.Open( sConnection );

// as an attempt at optimization we now open
// the recordset here, not in DBGetRecords()
oRecordSet = Server.CreateObject ( \'ADODB.Recordset\' );
}

// ============================================
// tidies up after DBInitConnection
// ============================================
function DBReleaseConnection ( )
{
// don\'t release the connection if not connected!
if ( sConnection == undefined )
return;

// as an attempt at optimization we now close
// the recordset here, not in DBReleaseRecords()
if ( oRecordSet.State != 0 )
oRecordSet.Close();
oRecordSet = undefined;

oConnection.Close();
oConnection = undefined;

sConnection = undefined;
}

// ============================================
// executes the passed in SQL statement
// and returns the oRecordSet object
// ============================================
function DBGetRecords ( sSQL )
{
// remember that this can fail if passed garbage, and hence
// \'oRecordSet\' will already be \'closed\'
oRecordSet = oConnection.Execute( sSQL );
}

// ============================================
// tidies up after DBGetRecords
// ============================================
function DBReleaseRecords ( )
{
// IMPORTANT: THIS FUNCTION INTENTIONALLY BLANK
// as an attempt at optimization we now open/close
// the recordset with the connection, not separately
// so all code was moved to DBReleaseConnection.

// it is recommended that you still call this function as soon
// as the recordset is finished with.

// note that it is assumed by the caller that it is legal
// to call DBReleaseConnection without calling this function
}
%>