错误 - 200：使用 phpmailer 发送邮件时出现解析器错误

Question

I've just started using phpmailer to send mail instead of the basic mail function. I've added the phpmailer function to an ajax script to send a mail on a certain event. The script works perfectly fine on its own, but as soon as I add the $mail->send(); command, I get an error:

"Error - 200: parsererror"

It does work - the mail gets sent, but it doesn't return correctly to the calling procedure. I've cut down my code a bit to remove extra validations and functions that aren't relevant to this particular issue. The calling code is:

    jQuery('#save-supplier').click(function(e){
    e.preventDefault();
      
    $('#save-supplier').html('<i class="fa fa-cloud"></i> Saving...');
                                  
    var formData = new FormData($('#edit-supplier-form')[0]);
      
    $.ajax({
        type: "POST",
        url: "./ajax/ajaxSendphpMail.php",
        data: formData,
        contentType: false,
        processData:false,
        cache: false,
        dataType: 'json',
        success: function(data) {
            $(location).attr("href", "supplier.php?supplier_code=<?php echo $supplier_code; ?>");
        },
        error: function(data){
            var errorMessage = data.status + ': ' + data.statusText;
            alert('Error - ' + errorMessage);
            $('#save-supplier').html('<i class="fa fa-save mr-5"></i> Save Changes');
        }
    });
  
    return false;
});

});

And the script with the phpmailer command is:

    ob_start();
session_start();
require '../inc/_global/db_con.php';

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;
require '/var/www/vhosts/compleit.com/vendor/autoload.php';

try {
    $mail = new PHPMailer(true);

    //Server settings
    $mail->SMTPDebug = 0;
    $mail->isSMTP();
    $mail->Host       = 'compleit.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = 'smtp@compleit.com';
    $mail->Password   = 'cAp$xxxYY';
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    //Recipients
    $mail->setFrom('myemail@mydomain.com');
    $mail->addAddress('gavinb@compleit.com');
    $mail->addReplyTo('donotreply@mydomain.com');

    // Content
    $mail->isHTML(true);
    $mail->Subject = 'test email';
    $mail->Body    = 'email body';
    $mail->AltBody = 'email body';

    $mail->send();
} catch (Exception $e) {
    // no exception reporting - no need to know if email succeeded or failed
}

Previously, I was sending mail through the standard mail command and I had no problem. But now that I've switched to phpmailer and I get the 200 parsererror. The only way to stop that is to comment out the $mail->send() command.

Answer 1

There are a couple of obvious problems here. PHPMailer does almost nothing until you actually call send() , which is why you're only seeing stuff happening then.

Your JS is expecting valid JSON in responses, but you have SMTPDebug enabled, which will produce lots of output that's definitely not valid JSON, so set that to 0 or false . This is what's causing your parser error, and it will be visible in your browser's dev tools if you look at the XHR requests it logs.

You're also missing a content-type header in your response, so your script (if it's obeying the rules) will not parse the response. Add a line before you produce any JSON output:

header('Content-type: application/json');

In the case of a successful send, you're not echo ing anything.

In debug situations like this, debug the individual components first . Make sure your PHP code is working (both success and failure paths) before you try to use it from JS. At the moment you're trying to debug your PHP code from JS, which is unnecessarily difficult.