一个免费的邮件列表源程序(三)

网络整理 - 07-26

Subscribe.asp
<%@ Language=Javascript %>




<%
// 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 */ %>





<%
// ============================================
// the content of this page
// ============================================
function Content ( )
{
   Out ( '<td> </td>' );
   Out ( '<td>' );

      // 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 cellpadding="0">' );
            Out ( '<tr><td valign="top">' );
               Out ( 'Email:' );
            Out ( '</td><td 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" size="31" value="' + sEmail + '"></input>' );
            Out ( '</td></tr>' );

            Out ( '<tr><td valign="top">' );
               Out ( ' ' );
            Out ( '</td><td 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" value="Subscribe"></input> <input type="submit" 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="http://www.newasp.net/Article/asp/example/2005/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> </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 to unsubscribe.\n\nThank you.\n\nJames Shaw\n' );
}

// ============================================
// 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 to re-subscribe.\n\nThank you.\n\nJames Shaw\n' );
}

// ============================================
// 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
}
%>