Bagaimana untuk menggunakan fungsi PHP untuk memproses format kandungan menghantar dan menerima e-mel?

$to = "recipient@example.com";
$subject = "Testing email";
$message = "This is a test email.";

$headers = "From: sender@example.com
";
$headers .= "MIME-Version: 1.0
";
$headers .= "Content-Type: text/plain; charset=UTF-8
";

mail($to, $subject, $message, $headers);

$mailbox = imap_open("{mail.example.com:993/imap/ssl}INBOX", "username", "password");

$messageCount = imap_num_msg($mailbox);

for ($i = 1; $i <= $messageCount; $i++) {
    $header = imap_header($mailbox, $i);
    $subject = $header->subject;
    $fromAddress = $header->fromaddress;
    
    $message = imap_fetchbody($mailbox, $i, 1);
    
    // 处理邮件内容
    // ...
}

imap_close($mailbox);

require 'vendor/autoload.php';

use PHPMailerPHPMailerPHPMailer;
use PHPMailerPHPMailerException;

$mail = new PHPMailer(true);

try {
    // 邮件服务器配置
    $mail->isSMTP();
    $mail->Host = 'smtp.example.com';
    $mail->SMTPAuth = true;
    $mail->Username = 'username';
    $mail->Password = 'password';
    $mail->SMTPSecure = 'tls';
    $mail->Port = 587;

    // 邮件内容配置
    $mail->setFrom('sender@example.com', 'Sender Name');
    $mail->addAddress('recipient@example.com', 'Recipient Name');
    $mail->Subject = 'Testing email';
    $mail->isHTML(true);
    $mail->Body = '<h1>This is a test email.</h1>';

    $mail->send();
    echo 'Email has been sent.';
} catch (Exception $e) {
    echo 'Email could not be sent. Error: ', $mail->ErrorInfo;
}

$mailbox = imap_open("{mail.example.com:993/imap/ssl}INBOX", "username", "password");

$messageCount = imap_num_msg($mailbox);

for ($i = 1; $i <= $messageCount; $i++) {
    $header = imap_header($mailbox, $i);
    $subject = $header->subject;
    $fromAddress = $header->fromaddress;
    
    $message = imap_fetchbody($mailbox, $i, 2);
    
    // 处理邮件内容
    // ...
}

imap_close($mailbox);

require 'vendor/autoload.php';

use PHPMailerPHPMailerPHPMailer;
use PHPMailerPHPMailerException;

$mail = new PHPMailer(true);

try {
    // 邮件服务器配置
    $mail->isSMTP();
    $mail->Host = 'smtp.example.com';
    $mail->SMTPAuth = true;
    $mail->Username = 'username';
    $mail->Password = 'password';
    $mail->SMTPSecure = 'tls';
    $mail->Port = 587;

    // 邮件内容配置
    $mail->setFrom('sender@example.com', 'Sender Name');
    $mail->addAddress('recipient@example.com', 'Recipient Name');
    $mail->Subject = 'Testing email';
    $mail->isHTML(true);
    $mail->Body = '<h1>This is a test email.</h1>';
    
    // 添加附件
    $mail->addAttachment('/path/to/file.pdf');

    $mail->send();
    echo 'Email has been sent.';
} catch (Exception $e) {
    echo 'Email could not be sent. Error: ', $mail->ErrorInfo;
}

$mailbox = imap_open("{mail.example.com:993/imap/ssl}INBOX", "username", "password");

$messageCount = imap_num_msg($mailbox);

for ($i = 1; $i <= $messageCount; $i++) {
    $header = imap_header($mailbox, $i);
    $subject = $header->subject;
    $fromAddress = $header->fromaddress;
    
    $structure = imap_fetchstructure($mailbox, $i);
    
    // 遍历附件
    foreach ($structure->parts as $partNum => $part) {
        if ($part->ifdparameters) {
            foreach ($part->dparameters as $param) {
                if (strtolower($param->attribute) == 'filename') {
                    $attachmentName = $param->value;
                    $attachmentData = imap_fetchbody($mailbox, $i, $partNum+1);

                    // 保存附件到本地
                    file_put_contents($attachmentName, $attachmentData);

                    // 处理附件
                    // ...
                }
            }
        }
    }

    // 处理邮件内容
    // ...
}

imap_close($mailbox);