Zend Framework：尝试使用Zend Mail Transport发送带附件的多封电子邮件时出现致命错误

Question

I don't totally understand how all this works, but I'm getting this error:

Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 261858 bytes) in /Users/andrew/Sites/myApp/library/Zend/Mail/Transport/Smtp.php on line 213

I'm running this code locally on my Mac running MAMP. Not sure if that has anything to do with it. This is my code, basically:

$config = array('ssl' => 'tls', 'port' => 587, 'auth' => 'login', 'username' => 'username', 'password' => 'password');
    $smtpConnection = new Zend_Mail_Transport_Smtp('smtp.gmail.com', $config);

    foreach ($subscribers as $subscriber) {
        $message = new Zend_Mail('utf-8');
        $message->setFrom('my@mailinglist.com', 'Mailing List')
                ->addTo($subscriber->email)
                ->setSubject($subject)
                ->setBodyText($body);
        $attachment = $message->createAttachment(file_get_contents($filepath));
        $attachment->type = 'application/pdf';
        $attachment->filename = $filename;
        $message->send($smtpConnection);
    }

However, the more subscribers there are, the higher this number ends up getting, and this fix will only help for so long:

ini_set("memory_limit","12M");

I need to figure out how to send an email with an attachment to a couple hundred people. Here's something else I've come up with but it seems a little hacky to only set the bcc and not the to address:

$message = new Zend_Mail('utf-8');
    $message->setFrom('my@mailinglist.com', 'Mailing list')
            ->setSubject($subject)
            ->setBodyText($body);
    $attachment = $message->createAttachment(file_get_contents($filepath));
    $attachment->type = 'application/pdf';
    $attachment->filename = $filename;

    foreach ($subscribers as $subscriber) {
        $message->addBcc($subscriber->email);
    }
    $message->send($smtpConnection);

However, even doing this, I need to specify the "memory_limit". Can you please point me in the right direction with this? Is there something I'm not doing?

Answer 1

I'm guessing your pdf is about 250Kbytes? You're reading it into memory once per email you send out. Don't. Read it once. :) It might also be an encoding-thing in the Zend framework.

• Call file_get_contents() once before your loop
• Set the memory limit much higher as long as your server can handle it (I'd say along the lines of 32-128 Mbytes)
• unset() your variables - should force php to GC it (in theory)
• You could reuse the $message object (ugly hack, but could save bytes if Zend does some sort of file-encoding and it uses lots of memory)

I'd also make a cron-job for sending the emails, and making sure that each email (or a reference to it) is stored in the database along with a status. This way you won't send duplicate mails if you hit another memory limit, or bug.

Answer 2

There's no need to create a new attachment with each message. Just create it once and then attach it each time you send.

$config = array('ssl' => 'tls', 'port' => 587, 'auth' => 'login', 'username' => 'username', 'password' => 'password');
$smtpConnection = new Zend_Mail_Transport_Smtp('smtp.gmail.com', $config);

$attachment = new Zend_Mime_Part(file_get_contents($filepath));
$attachment->type = 'application/pdf';
$attachment->disposition = Zend_Mime::DISPOSITION_ATTACHMENT;
$attachment->filename = $filename;

foreach ($subscribers as $subscriber) {
    $message = new Zend_Mail('utf-8');
    $message->setFrom('my@mailinglist.com', 'Mailing List')
            ->addTo($subscriber->email)
            ->setSubject($subject)
            ->setBodyText($body);
    $message->addAttachment($attachment);
    $message->send($smtpConnection);
}

Answer 3

I have had the similar problem with memory limit and sending by one SMTP connection for a lot of messages. Zend_Mail_Protocol_Abstract holds its internal log in memory. There are logged all mail requests in the log. The log is growing up with each message sent. You has to call $protocol->resetLog() sometimes. (It depends on your data amount for each message. You can check your memory use by memory_get_usage() PHP function.) Try something like this:

  $transport = new Zend_Mail_Transport_Smtp();
  $protocol = new Zend_Mail_Protocol_Smtp('localhost');
  $protocol->connect();
  $protocol->helo('localhost');
  $transport->setConnection($protocol);
  foreach(){
    $mail = new Zend_Mail('utf-8');
    ...
    $protocol->rset();
    $mail->send($transport);
    $protocol->resetLog();  // you don't need to resetLog for each message
  }

This also might be helpful: http://framework.zend.com/manual/en/zend.mail.multiple-emails.html