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    <h3>Editing: SwiftMailerHandler.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);

/*
 * This file is part of the Monolog package.
 *
 * (c) Jordi Boggiano &lt;j.boggiano@seld.be&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Monolog\Handler;

use Monolog\Logger;
use Monolog\Utils;
use Monolog\Formatter\FormatterInterface;
use Monolog\Formatter\LineFormatter;
use Swift_Message;
use Swift;

/**
 * SwiftMailerHandler uses Swift_Mailer to send the emails
 *
 * @author Gyula Sallai
 *
 * @phpstan-import-type Record from \Monolog\Logger
 * @deprecated Since Monolog 2.6. Use SymfonyMailerHandler instead.
 */
class SwiftMailerHandler extends MailHandler
{
    /** @var \Swift_Mailer */
    protected $mailer;
    /** @var Swift_Message|callable(string, Record[]): Swift_Message */
    private $messageTemplate;

    /**
     * @psalm-param Swift_Message|callable(string, Record[]): Swift_Message $message
     *
     * @param \Swift_Mailer          $mailer  The mailer to use
     * @param callable|Swift_Message $message An example message for real messages, only the body will be replaced
     */
    public function __construct(\Swift_Mailer $mailer, $message, $level = Logger::ERROR, bool $bubble = true)
    {
        parent::__construct($level, $bubble);

        @trigger_error('The SwiftMailerHandler is deprecated since Monolog 2.6. Use SymfonyMailerHandler instead.', E_USER_DEPRECATED);

        $this-&gt;mailer = $mailer;
        $this-&gt;messageTemplate = $message;
    }

    /**
     * {@inheritDoc}
     */
    protected function send(string $content, array $records): void
    {
        $this-&gt;mailer-&gt;send($this-&gt;buildMessage($content, $records));
    }

    /**
     * Gets the formatter for the Swift_Message subject.
     *
     * @param string|null $format The format of the subject
     */
    protected function getSubjectFormatter(?string $format): FormatterInterface
    {
        return new LineFormatter($format);
    }

    /**
     * Creates instance of Swift_Message to be sent
     *
     * @param  string        $content formatted email body to be sent
     * @param  array         $records Log records that formed the content
     * @return Swift_Message
     *
     * @phpstan-param Record[] $records
     */
    protected function buildMessage(string $content, array $records): Swift_Message
    {
        $message = null;
        if ($this-&gt;messageTemplate instanceof Swift_Message) {
            $message = clone $this-&gt;messageTemplate;
            $message-&gt;generateId();
        } elseif (is_callable($this-&gt;messageTemplate)) {
            $message = ($this-&gt;messageTemplate)($content, $records);
        }

        if (!$message instanceof Swift_Message) {
            $record = reset($records);
            throw new \InvalidArgumentException('Could not resolve message as instance of Swift_Message or a callable returning it' . ($record ? Utils::getRecordMessageForException($record) : ''));
        }

        if ($records) {
            $subjectFormatter = $this-&gt;getSubjectFormatter($message-&gt;getSubject());
            $message-&gt;setSubject($subjectFormatter-&gt;format($this-&gt;getHighestRecord($records)));
        }

        $mime = 'text/plain';
        if ($this-&gt;isHtmlBody($content)) {
            $mime = 'text/html';
        }

        $message-&gt;setBody($content, $mime);
        /** @phpstan-ignore-next-line */
        if (version_compare(Swift::VERSION, '6.0.0', '&gt;=')) {
            $message-&gt;setDate(new \DateTimeImmutable());
        } else {
            /** @phpstan-ignore-next-line */
            $message-&gt;setDate(time());
        }

        return $message;
    }
}
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