使用 Zend_Mail 时添加 PDF 附件

使用 Zend_Mail 时添加附件的正确方法是什么？当我尝试打开已发送邮件中附加的 pdf 时，不断收到以下错误：“无法提取嵌入字体 'BAAAAAA+ArialMT'。某些字符可能无法正确显示或打印。” PDF 仅显示表格，不显示字符。

这很奇怪，因为如果我直接从服务器或本地主机下载 PDF，它就会正确打开。

这是我用于发送附件的代码：

$html = $view->render('email/invoice.phtml');
$mail = new Zend_Mail("utf-8");

$file = PUBLIC_PATH . DS . 'data' . DS . $invoice . '.pdf';
$at = new Zend_Mime_Part(file_get_contents($file));
$at->filename = basename($file);
$at->disposition = Zend_Mime::DISPOSITION_ATTACHMENT;
$at->encoding = Zend_Mime::ENCODING_8BIT;
$mail->addAttachment($at);

/* Here i add the attachment */
$mail->setBodyHtml($html);
$mail->addTo($order->email, 'Factura '. $invoice . ' '.Zend_Registry::get('siteName'));
$mail->setFrom('[email protected]', Zend_Registry::get('siteName'));
$mail->setSubject('Factura '. $invoice . ' '.Zend_Registry::get('siteName'));
$mail->send();

这是正确的做法，

$mail = new Zend_Mail();
$mail->setBodyHtml("description");
$mail->setFrom('id', 'name');
$mail->addTo(email, name);
$mail->setSubject(subject);

$content = file_get_contents("path to pdf file"); // e.g. ("attachment/abc.pdf")
$attachment = new Zend_Mime_Part($content);
$attachment->type = 'application/pdf';
$attachment->disposition = Zend_Mime::DISPOSITION_ATTACHMENT;
$attachment->encoding = Zend_Mime::ENCODING_BASE64;
$attachment->filename = 'filename.pdf'; // name of file

$mail->addAttachment($attachment);                  

$mail->send();