HTML

HTML中只有两个要求用于发送文件附件。

您的表单需要具有以下属性：enctype="multipart/form-data"
您至少需要一个像<input type="file" name="examplefile">这样的字段。这允许用户浏览要附加的文件。

如果您同时拥有这两项，浏览器将上传所有附加文件以及表单提交。

旁注：这些文件在服务器上保存为临时文件。对于此示例，我们将获取他们的数据并通过电子邮件发送，但如果您将临时文件移动到永久位置，则您刚刚创建了一个文件上载表单。

MIME电子邮件格式

This tutorial非常适合理解如何在PHP中构建MIME电子邮件（可以包含HTML内容，纯文本版本，附件等）。我用它作为起点。

基本上，你做了三件事：

预先声明此电子邮件中包含多种类型的内容
声明将用于分隔不同部分的文本字符串
定义每个部分并坚持使用适当的内容。对于文件附件，您必须指定类型并以ASCII格式对其进行编码。
- 每个部分都有一个content-type，例如image/jpg或application/pdf.可以找到更多信息here。（我的示例脚本使用内置的PHP函数从每个文件中提取此信息。）

PHP

提交表单后，浏览器上传的任何文件（请参阅HTML部分）都可以通过$_FILES变量获得，该变量包含'通过HTTP POST上传到当前脚本的关联数组项方法。'

$_FILES上的documentation很糟糕，但上传后，您可以运行print_r($_FILES)查看其工作原理。它将输出如下内容：

Array ( [examplefile] => Array ( [name] => your_filename.txt 
[type] => text/plain [tmp_name] => 
C:\path\to\tmp\file\something.tmp [error] => 0 [size] => 200 ) )

然后，您可以使用file_get_contents($_FILES['examplefile']['tmp_name'])获取相关临时文件中的数据。

关于文件大小限制的附注

php.ini有一些限制附件大小的设置。有关详细信息，请参阅this discussion。

示例PHP函数

我创建了以下功能，该功能可以包含在页面上，用于收集随表单提交的任何文件附件。随意使用和/或根据您的需要进行调整。

总附件限制是任意的，但是大量可能会使mail()脚本陷入困境或被发送或接收电子邮件服务器拒绝。做自己的测试。

（注意：PHP中的mail()函数取决于php.ini中了解如何发送电子邮件的信息。）

function sendWithAttachments($to, $subject, $htmlMessage){
  $maxTotalAttachments=2097152; //Maximum of 2 MB total attachments, in bytes
  $boundary_text = "anyRandomStringOfCharactersThatIsUnlikelyToAppearInEmail";
  $boundary = "--".$boundary_text."\r\n";
  $boundary_last = "--".$boundary_text."--\r\n";

  //Build up the list of attachments, 
  //getting a total size and adding boundaries as needed
  $emailAttachments = "";
  $totalAttachmentSize = 0;
  foreach ($_FILES as $file) {
    //In case some file inputs are left blank - ignore them
    if ($file['error'] == 0 && $file['size'] > 0){
      $fileContents = file_get_contents($file['tmp_name']);
      $totalAttachmentSize += $file['size']; //size in bytes
      $emailAttachments .= "Content-Type: " 
      .$file['type'] . "; name=\"" . basename($file['name']) . "\"\r\n"
      ."Content-Transfer-Encoding: base64\r\n"
      ."Content-disposition: attachment; filename=\"" 
      .basename($file['name']) . "\"\r\n"
      ."\r\n"
      //Convert the file's binary info into ASCII characters
      .chunk_split(base64_encode($fileContents))
      .$boundary;
    }
  }
  //Now all the attachment data is ready to insert into the email body.
  //If the file was too big for PHP, it may show as having 0 size
  if ($totalAttachmentSize == 0) {
    echo "Message not sent. Either no file was attached, or it was bigger than PHP is configured to accept.";
   }
  //Now make sure it doesn't exceed this function's specified limit:
  else if ($totalAttachmentSize>$maxTotalAttachments) {
    echo "Message not sent. Total attachments can't exceed " .  $maxTotalAttachments . " bytes.";
  }
  //Everything is OK - let's build up the email
  else {    
    $headers =  "From: yourserver@example.com\r\n";
    $headers .=     "MIME-Version: 1.0\r\n"
    ."Content-Type: multipart/mixed; boundary=\"$boundary_text\"" . "\r\n";  
    $body .="If you can see this, your email client "
    ."doesn't accept MIME types!\r\n"
    .$boundary;

    //Insert the attachment information we built up above.
    //Each of those attachments ends in a regular boundary string    
    $body .= $emailAttachments;

    $body .= "Content-Type: text/html; charset=\"iso-8859-1\"\r\n"
    ."Content-Transfer-Encoding: 7bit\r\n\r\n"
    //Inert the HTML message body you passed into this function
    .$htmlMessage . "\r\n"
    //This section ends in a terminating boundary string - meaning
    //"that was the last section, we're done"
    .$boundary_last;

    if(mail($to, $subject, $body, $headers))
    {
      echo "<h2>Thanks!</h2>Form submitted to " . $to . "<br />";
    } else {
      echo 'Error - mail not sent.';
    }
  }    
}

如果你想看看这里发生了什么，请注释掉mail()的号码，然后将输出反映到你的屏幕上。

Answer 2

为了发送实际的电子邮件，我建议使用PHPMailer library，这会让一切变得更加轻松。

Answer 3

很好tutorial here

代码

<?php
//define the receiver of the email
$to = 'youraddress@example.com';
//define the subject of the email
$subject = 'Test email with attachment';
//create a boundary string. It must be unique
//so we use the MD5 algorithm to generate a random hash
$random_hash = md5(date('r', time()));
//define the headers we want passed. Note that they are separated with \r\n
$headers = "From: webmaster@example.com\r\nReply-To: webmaster@example.com";
//add boundary string and mime type specification
$headers .= "\r\nContent-Type: multipart/mixed; boundary=\"PHP-mixed-".$random_hash."\"";
//read the atachment file contents into a string,
//encode it with MIME base64,
//and split it into smaller chunks
$attachment = chunk_split(base64_encode(file_get_contents('attachment.zip')));
//define the body of the message.
ob_start(); //Turn on output buffering
?>
--PHP-mixed-<?php echo $random_hash; ?> 
Content-Type: multipart/alternative; boundary="PHP-alt-<?php echo $random_hash; ?>"

--PHP-alt-<?php echo $random_hash; ?> 
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Hello World!!!
This is simple text email message.

--PHP-alt-<?php echo $random_hash; ?> 
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

<h2>Hello World!</h2>
<p>This is something with <b>HTML</b> formatting.</p>

--PHP-alt-<?php echo $random_hash; ?>--

--PHP-mixed-<?php echo $random_hash; ?> 
Content-Type: application/zip; name="attachment.zip" 
Content-Transfer-Encoding: base64 
Content-Disposition: attachment 

<?php echo $attachment; ?>
--PHP-mixed-<?php echo $random_hash; ?>--

<?php
//copy current buffer contents into $message variable and delete current output buffer
$message = ob_get_clean();
//send the email
$mail_sent = @mail( $to, $subject, $message, $headers );
//if the message is sent successfully print "Mail sent". Otherwise print "Mail failed"
echo $mail_sent ? "Mail sent" : "Mail failed";
?>

Answer 4

您可能想查看SwiftMailer。它有一个很好的tutorial on this。

如何从PHP表单发送带附件的电子邮件？

4 个答案:

HTML

MIME电子邮件格式

PHP

关于文件大小限制的附注

示例PHP函数