PHP：附加 base64 图像的 mail() 以文本形式显示

Question

我一直在尝试将图像编码为 base64，然后使用 php mail() 将其作为电子邮件附件发送，但我得到的只是电子邮件中的 base64 文本。这是我正在使用的：

$boundary1 = 'bound1';
$boundary2 = 'bound2';
$to = '[email protected]';  
$subject = 'Test Image attachment'; 
$headers = 'From: "Me" <[email protected]>'."\r\n"; 
//add boundary string and mime type specification 
$headers .= "MIME-Version: 1.0\r\n"; 
$headers .= "Content-Type: multipart/mixed; boundary=\"$boundary1\""; 
//define the body of the message. 
$message = 'Content-Type: image/png; name="'.$file_name.'"'."\n"; 
$message .= "Content-Transfer-Encoding: base64\n"; 
$message .= "Content-Disposition: inline; filename=\"$file_name\"\n\n";
$message .= base64_encode_image("signature_files/".$file_name, 'png')."\n";
$message .= "--" . $boundary2 . "\n";
//send the email 
mail( $to, $subject, $message, $headers);

// Function to encode an image
function base64_encode_image($filename=string,$filetype=string) {
    if ($filename) {
        $imgbinary = fread(fopen($filename, "r"), filesize($filename));
        return 'data:image/' . $filetype . ';base64,' . chunk_split(base64_encode($imgbinary), 64, "\n");
    }
}

有人看到这段代码有什么问题吗？真的不知道为什么当我收到电子邮件时只看到原始文本。

Answer 1

这是发送带有内联 Base64 图像的 HTML 电子邮件的正确方法：

<?php
$boundary = md5(uniqid(time()));

$header[] = "MIME-Version: 1.0";
$header[] = "Content-Type: Multipart/Mixed; Boundary=\"$boundary\"";
$header[] = "Content-Transfer-Encoding: 7bit";
$header[] = "From: John Doe <[email protected]>";
$header[] = "Reply-To: John Doe <[email protected]>";
$header[] = "X-Mailer: PHP/".phpversion();

$msg[] = "";
$msg[] = "--{$boundary}";
$msg[] = "Content-Type: text/html; charset=ISO-8859-1";
$msg[] = "";
$msg[] = "<p>YOUR HTML CONTENT</p> <img src=\"cid:logo\" alt=\"Logo\">";
$msg[] = "";
//HERE YOU MUST ATTACH THE IMAGE
//===============================================
$image = chunk_split(YOUR_IMAGE_ENCODED_IN_BASE64);
$msg[] = "--{$boundary}";
$msg[] = "Content-Type: image/png; name=\"logo.png\"";
$msg[] = "Content-ID: <logo>";
$msg[] = "Content-Description: Attachment";
$msg[] = "Content-Transfer-Encoding: base64";
$msg[] = "Content-Disposition: inline; filename=\"logo.png\"";
$msg[] = "";
$msg[] = $image;
$msg[] = "";

$msg[] = "--{$boundary}--";
mail($mailto, $subject, implode("\r\n", $msg), implode("\r\n", $header));

这里重要的部分是内容 id 引用，因此，首先，您必须定义图像 id，在本例中，id 是 logo ，所以，在附件中，你必须定义content ID header：

Content-ID: <logo>

然后，在HTML内容中，你可以通过content ID调用或附加内联这张图片，如下所示：

<img src="cid:logo" alt="Logo">

Answer 2

您分别在邮件标头和 MIME 附件部分标头中混合 \r\n 和 \n\n 。尝试将它们全部更改为 \r\n。

另一种可能性 - 如果您尝试附加图像，而不是内联显示，请使用 Content-disposition:attachment;

$message .= "Content-Disposition: attachment; filename=\"$file_name\"\n\n";