我最终编写了自己的电子邮件发送/编码函数。这在我发送PDF附件时效果很好。我还没有在生产中使用其他特性。

注意:尽管规范非常强调必须使用\r\n来分隔头文件，但我发现它只在使用PHP_EOL时有效。我只在Linux上测试过这个功能。YMMV

<?php
# $args must be an associative array
#     required keys: from, to, body
#          body can be a string or a [tree of] associative arrays. See examples below
#     optional keys: subject, reply_to, cc, bcc
# EXAMPLES:
#    # text-only email:
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        # body will be text/plain because we're passing a string that doesn't start with '<'
#        'body' => 'Hi, testing 1 2 3',
#    ));
#
#    # html-only email
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        # body will be text/html because we're passing a string that starts with '<'
#        'body' => '<h1>Hi!</h1>I like <a href="http://cheese.com">cheese</a>',
#    ));
#
#    # text-only email (explicitly, in case first character is dynamic or something)
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        # body will be text/plain because we're passing a string that doesn't start with '<'
#        'body' => array(
#            'type' => 'text',
#            'body' => $message_text,
#        )
#    ));
#
#    # email with text and html alternatives (auto-detected mime types)
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        'body' => array(
#            'type' => 'alternatives',
#            'body' => array(
#                "Hi!\n\nI like cheese",
#                '<h1>Hi!</h1><p>I like <a href="http://cheese.com">cheese</a></p>',
#            )
#        )
#    ));
#
#    # email with text and html alternatives (explicit types)
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        'body' => array(
#            'type' => 'alternatives',
#            'body' => array(
#                array(
#                    'type' => 'text',
#                    'body' => "Hi!\n\nI like cheese",
#                ),
#                array(
#                    'type' => 'html',
#                    'body' => '<h1>Hi!</h1><p>I like cheese</p>',
#                ),
#            )
#        )
#    ));
#
#    # email with an attachment
#    email2(array(
#        'from' => 'noreply@foo.com',
#        'to' => 'jason@jasonwoof.com',
#        'subject' => 'test',
#        'body' => array(
#            'type' => 'mixed',
#            'body' => array(
#                "Hi!\n\nCheck out this (inline) image",
#                array(
#                    'type' => 'image/png',
#                    'disposition' => 'inline',
#                    'body' => $image_data, # raw file contents
#                ),
#                "Hi!\n\nAnd here's an attachment",
#                array(
#                    'type' => 'application/pdf; name="attachment.pdf"',
#                    'disposition' => 'attachment; filename="attachment.pdf"',
#                    'body' => $pdf_data, # raw file contents
#                ),
#                "Or you can use shorthand:",
#                array(
#                    'type' => 'application/pdf',
#                    'attachment' => 'attachment.pdf', # name for client (not data source)
#                    'body' => $pdf_data, # raw file contents
#                ),
#            )
#        )
#    ))
function email2($args) {
    if (!isset($args['from'])) { return 1; }
    $from = $args['from'];
    if (!isset($args['to'])) { return 2; }
    $to = $args['to'];
    $subject = isset($args['subject']) ? $args['subject'] : '';
    $reply_to = isset($args['reply_to']) ? $args['reply_to'] : '';
    $cc = isset($args['cc']) ? $args['cc'] : '';
    $bcc = isset($args['bcc']) ? $args['bcc'] : '';

    #FIXME should allow many more characters here (and do Q encoding)
    $subject = isset($args['subject']) ? $args['subject'] : '';
    $subject = preg_replace("|[^a-z0-9 _/#'.:&,-]|i", '_', $subject);

    $headers = "From: $from";
    if($reply_to) {
        $headers .= PHP_EOL . "Reply-To: $reply_to";
    }
    if($cc) {
        $headers .= PHP_EOL . "CC: $cc";
    }
    if($bcc) {
        $headers .= PHP_EOL . "BCC: $bcc";
    }

    $r = email2_helper($args['body']);
    $headers .= PHP_EOL . $r[0];
    $body = $r[1];

    if (mail($to, $subject, $body, $headers)) {
        return 0;
    } else {
        return 5;
    }
}

function email2_helper($body, $top = true) {
    if (is_string($body)) {
        if (substr($body, 0, 1) == '<') {
            return email2_helper(array('type' => 'html', 'body' => $body), $top);
        } else {
            return email2_helper(array('type' => 'text', 'body' => $body), $top);
        }
    }
    # now we can assume $body is an associative array
    # defaults:
    $type = 'application/octet-stream';
    $mime = false;
    $boundary = null;
    $disposition = null;
    $charset = false;
    # process 'type' first, because it sets defaults for others
    if (isset($body['type'])) {
        $type = $body['type'];
        if ($type === 'text') {
            $type = 'text/plain';
            $charset = true;
        } elseif ($type === 'html') {
            $type = 'text/html';
            $charset = true;
        } elseif ($type === 'alternative' || $type === 'alternatives') {
            $mime = true;
            $type = 'multipart/alternative';
        } elseif ($type === 'mixed') {
            $mime = true;
            $type = 'multipart/mixed';
        }
    }
    if (isset($body['disposition'])) {
        $disposition = $body['disposition'];
    }
    if (isset($body['attachment'])) {
        if ($disposition == null) {
            $disposition = 'attachment';
        }
        $disposition .= "; filename=\"{$body['attachment']}\"";
        $type .= "; name=\"{$body['attachment']}\"";
    }
    # make headers
    $headers = array();
    if ($top && $mime) {
        $headers[] = 'MIME-Version: 1.0';
    }
    if ($mime) {
        $boundary = md5('5sd^%Ca)~aAfF0=4mIN' . rand() . rand());
        $type .= "; boundary=$boundary";
    }
    if ($charset) {
        $type .= '; charset=' . (isset($body['charset']) ? $body['charset'] : 'UTF-8');
    }
    $headers[] = "Content-Type: $type";
    if ($disposition !== null) {
        $headers[] = "Content-Disposition: {$disposition}";
    }

    $data = '';
    # return array, first el is headers, 2nd is body (php's mail() needs them separate)
    if ($mime) {
        foreach ($body['body'] as $sub_body) {
            $data .= "--$boundary" . PHP_EOL;
            $r = email2_helper($sub_body, false);
            $data .= $r[0] . PHP_EOL . PHP_EOL; # headers
            $data .= $r[1] . PHP_EOL . PHP_EOL; # body
        }
        $data .= "--$boundary--";
    } else {
        if(preg_match('/[^\x09\x0A\x0D\x20-\x7E]/', $body['body'])) {
            $headers[] = "Content-Transfer-Encoding: base64";
            $data .= chunk_split(base64_encode($body['body']));
        } else {
            $data .= $body['body'];
        }
    }
    return array(join(PHP_EOL, $headers), $data);
}

从此页复制代码-在mail()中工作

他首先创建了一个可以稍后调用的mail_attachment函数。他稍后用他的附件代码来做。

<?php
function mail_attachment($filename, $path, $mailto, $from_mail, $from_name, $replyto, $subject, $message) {
    $file = $path.$filename;
    $file_size = filesize($file);
    $handle = fopen($file, "r");
    $content = fread($handle, $file_size);
    fclose($handle);
    $content = chunk_split(base64_encode($content));
    $uid = md5(uniqid(time()));
    $header = "From: ".$from_name." <".$from_mail.">\r\n";
    $header .= "Reply-To: ".$replyto."\r\n";
    $header .= "MIME-Version: 1.0\r\n";
    $header .= "Content-Type: multipart/mixed; boundary=\"".$uid."\"\r\n\r\n";
    $header .= "This is a multi-part message in MIME format.\r\n";
    $header .= "--".$uid."\r\n";
    $header .= "Content-type:text/plain; charset=iso-8859-1\r\n";
    $header .= "Content-Transfer-Encoding: 7bit\r\n\r\n";
    $header .= $message."\r\n\r\n";
    $header .= "--".$uid."\r\n";
    $header .= "Content-Type: application/octet-stream; name=\"".$filename."\"\r\n"; // use different content types here
    $header .= "Content-Transfer-Encoding: base64\r\n";
    $header .= "Content-Disposition: attachment; filename=\"".$filename."\"\r\n\r\n";
    $header .= $content."\r\n\r\n";
    $header .= "--".$uid."--";
    if (mail($mailto, $subject, "", $header)) {
        echo "mail send ... OK"; // or use booleans here
    } else {
        echo "mail send ... ERROR!";
    }
}

//start editing and inputting attachment details here
$my_file = "somefile.zip";
$my_path = "/your_path/to_the_attachment/";
$my_name = "Olaf Lederer";
$my_mail = "my@mail.com";
$my_replyto = "my_reply_to@mail.net";
$my_subject = "This is a mail with attachment.";
$my_message = "Hallo,\r\ndo you like this script? I hope it will help.\r\n\r\ngr. Olaf";
mail_attachment($my_file, $my_path, "recipient@mail.org", $my_mail, $my_name, $my_replyto, $my_subject, $my_message);
?>

他在他的页面上有更多的细节，并在评论区回答了一些问题。

这对我很有用。它还附加了多个附件。很容易

<?php

if ($_POST && isset($_FILES['file'])) {
    $recipient_email = "recipient@yourmail.com"; //recepient
    $from_email = "info@your_domain.com"; //from email using site domain.
    $subject = "Attachment email from your website!"; //email subject line

    $sender_name = filter_var($_POST["s_name"], FILTER_SANITIZE_STRING); //capture sender name
    $sender_email = filter_var($_POST["s_email"], FILTER_SANITIZE_STRING); //capture sender email
    $sender_message = filter_var($_POST["s_message"], FILTER_SANITIZE_STRING); //capture message
    $attachments = $_FILES['file'];

    //php validation
    if (strlen($sender_name) < 4) {
        die('Name is too short or empty');
    }
    if (!filter_var($sender_email, FILTER_VALIDATE_EMAIL)) {
        die('Invalid email');
    }
    if (strlen($sender_message) < 4) {
        die('Too short message! Please enter something');
    }

    $file_count = count($attachments['name']); //count total files attached
    $boundary = md5("specialToken$4332"); // boundary token to be used

    if ($file_count > 0) { //if attachment exists
        //header
        $headers = "MIME-Version: 1.0\r\n";
        $headers .= "From:" . $from_email . "\r\n";
        $headers .= "Reply-To: " . $sender_email . "" . "\r\n";
        $headers .= "Content-Type: multipart/mixed; boundary = $boundary\r\n\r\n";

        //message text
        $body = "--$boundary\r\n";
        $body .= "Content-Type: text/plain; charset=ISO-8859-1\r\n";
        $body .= "Content-Transfer-Encoding: base64\r\n\r\n";
        $body .= chunk_split(base64_encode($sender_message));

        //attachments
        for ($x = 0; $x < $file_count; $x++) {
            if (!empty($attachments['name'][$x])) {

                if ($attachments['error'][$x] > 0) { //exit script and output error if we encounter any
                    $mymsg = array(
                        1 => "The uploaded file exceeds the upload_max_filesize directive in php.ini",
                        2 => "The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form",
                        3 => "The uploaded file was only partially uploaded",
                        4 => "No file was uploaded",
                        6 => "Missing a temporary folder");
                    die($mymsg[$attachments['error'][$x]]);
                }

                //get file info
                $file_name = $attachments['name'][$x];
                $file_size = $attachments['size'][$x];
                $file_type = $attachments['type'][$x];

                //read file 
                $handle = fopen($attachments['tmp_name'][$x], "r");
                $content = fread($handle, $file_size);
                fclose($handle);
                $encoded_content = chunk_split(base64_encode($content)); //split into smaller chunks (RFC 2045)

                $body .= "--$boundary\r\n";
                $body .= "Content-Type: $file_type; name=" . $file_name . "\r\n";
                $body .= "Content-Disposition: attachment; filename=" . $file_name . "\r\n";
                $body .= "Content-Transfer-Encoding: base64\r\n";
                $body .= "X-Attachment-Id: " . rand(1000, 99999) . "\r\n\r\n";
                $body .= $encoded_content;
            }
        }
    } else { //send plain email otherwise
        $headers = "From:" . $from_email . "\r\n" .
                "Reply-To: " . $sender_email . "\n" .
                "X-Mailer: PHP/" . phpversion();
        $body = $sender_message;
    }

    $sentMail = @mail($recipient_email, $subject, $body, $headers);
    if ($sentMail) { //output success or failure messages
        die('Thank you for your email');
    } else {
        die('Could not send mail! Please check your PHP mail configuration.');
    }
}
?>

在与格式糟糕的附件斗争了一段时间后，我使用了以下代码:

$email = new PHPMailer();
$email->From      = 'from@somedomain.com';
$email->FromName  = 'FromName';
$email->Subject   = 'Subject';
$email->Body      = 'Body';
$email->AddAddress( 'to@somedomain.com' );
$email->AddAttachment( "/path/to/filename.ext" , "filename.ext", 'base64', 'application/octet-stream' );
$email->Send();

我同意评论中的@MihaiIorga -使用PHPMailer脚本。听起来你拒绝是因为你想要更简单的选择。相信我，比起自己使用PHP内置的mail()函数，PHPMailer是一个更简单的选择。PHP的mail()函数真的不是很好。

使用PHPMailer:

下载PHPMailer脚本:http://github.com/PHPMailer/PHPMailer 提取归档文件并将脚本文件夹复制到项目中方便的位置。 包括主脚本文件——require_once('path/to/file/class.phpmailer.php');

现在，发送带有附件的电子邮件从异常困难变得异常简单:

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

$email = new PHPMailer();
$email->SetFrom('you@example.com', 'Your Name'); //Name is optional
$email->Subject   = 'Message Subject';
$email->Body      = $bodytext;
$email->AddAddress( 'destinationaddress@example.com' );

$file_to_attach = 'PATH_OF_YOUR_FILE_HERE';

$email->AddAttachment( $file_to_attach , 'NameOfFile.pdf' );

return $email->Send();

只有一行$email-> addatattachment ();——再简单不过了。

如果使用PHP的mail()函数，则需要编写大量代码，并且可能会遇到许多很难找到的错误。

Swiftmailer是另一个易于使用的脚本，可以自动防止电子邮件注入，使附件变得轻而易举。我也强烈反对使用PHP内置的mail()函数。

使用方法:

下载Swiftmailer，并将lib文件夹放在你的项目中 使用require_once 'lib/swift_required.php'包含主文件;

现在当你需要邮寄时添加代码:

// Create the message
$message = Swift_Message::newInstance()
    ->setSubject('Your subject')
    ->setFrom(array('webmaster@mysite.com' => 'Web Master'))
    ->setTo(array('receiver@example.com'))
    ->setBody('Here is the message itself')
    ->attach(Swift_Attachment::fromPath('myPDF.pdf'));

//send the message          
$mailer->send($message);

更多信息和选项可以在Swiftmailer文档中找到。