Newsletter mailing - need expert advice on app design.

I run an active forum with over 10,000 members. Around 7,000 of those members are opt-in newsletter subscribers.

The problem comes is that I cannot use forum software to distribute the newsletter because my hosting company sets a limit on outbound email traffic, so most of the emails will end up undelivered. On top of that, I don't want to load the server like that as one-time action - I would rather spread the load over a period of time.

So I need to create some sort of an application in which I can insert all the extracted email addresses in a regular text format (separated by comma or semicolumn). The application will then send the newsletter (in a text or HTML format (for that I attach the HTML file like you would with a Word document) in specified by me batches/numbers (ex: 200 emails at a time) and time periods (ex: every 2 hours). If necessary, I will also insert all the outgoing server information (which can actually give me the flexibility to use any of the sites I have as mail out point) and an email "face" account from which the mailing is done from.


Question: How do I approach it? How will you suggest building such an application? I am looking for some great ideas on how to solve this problem. I obviously don't care about the looks, just functionality - I need the best possible and reliable solution. Whether it is web-based or desktop-based doesn't make a difference.


PS: I had a script done a couple of years ago that looked just like a regular web form. As far as I know, it used "cron" to memorize the email list and send out emails according to my specifications. It worked fine, but every time I made changes to the server, the form/cron would break. So I need something different.

I really appreciate any input I can get! Please keep in mind that I am not strong on "technical" lingo.

Thank you in advance.

 

As you said, cron would break if changes made to server, yes it would definitely, but there is a solution, why not let the script clear all cron jobs and just add one new for sending the newsletter. And when job's done scirpt erases the cron job.

Secondly, I disagree sending 200 in 1 hour, I would suggest send 20 in 5 minutes, it will be ok, if the mail size is not too large. Sending 200 in one attempt may cause bottle-neck situation.

Now here is the prototype of the scripts


Script1.php - Admin Panel
Step 1. Extract all subscribers and save them to plain text file, such as

$res = mysql_query("SELECT email FROM your_table WHERE subscribed='Yes'");
$array = Array();
while($row = mysql_fetch_asoc($res)) 
     $array []= $row['email'];
$array = implode("\n",$array);

$f = fopen("newsletter.txt","w"); #write the file
fwrite($f,$array);
fclose($f);

Code (markup):

Step 2. Wipe up all cron jobs, and write new one

#clear all
$raw_arr = Array();
exec("crontab -r",$raw_arr);

Code (markup):

#set new
$path = dirname($_SERVER['SCRIPT_FILENAME']);
$job = "* * * * * php -q ".dirname($_SERVER['PHP_SELF'])."/newsletter.php";
$tmp_file = dirname($_SERVER['PHP_SELF'])."/tempfile.crn";
$f = fopen($tmp_file, "w");
fwrite($f, "$job\n");
fclose($f);		
$raw_arr=Array();
exec("crontab $tmp_file",$raw_arr);		
@unlink("$tmp_file");

Code (markup):

newsletter.php - the sender

$per_attempt = 20; #20 mails per attempt

#first check if already empty
if(file_size("newsletter.txt")==0) {
   #remove all cron job
   $raw_arr = Array();
   exec("crontab -r",$raw_arr);
   #delete temporary mails text file
   @unlink("newsletter.txt");
   die();
}

$arr = @file("newsletter.txt");

if($arr !== FALSE) {
   #take top N addresses
   $mails = array_slice($arr,0,$per_attempt);
   foreach($mails as $mail) {
      #send email to address "$email"
   }
   #write remaining to file for next attemp
   $arr = array_diff($arr,$mails);
   $f = fopen("newsletter.txt","w");
   fwrite($f,implode("\n",$arr);
   fclose($f);
}

Code (markup):

Using this way, you can get rid of opening extra mysql connections on each attempt. And save server load too.

Let me know if you need more help. I already coded such application for a mailing list that was used for more than 260,000 mails per day, and went perfect.

regards