PHP - 識別附件文件擴展名

Question

我正在導入帶有附件的電子郵件，然後將它們保存到臨時文件夾。問題是，一旦文件被保存到最終目錄中，它就沒有擴展名。

如何獲取附件的文件擴展名，然後將其附加到文件名？

/* iterate through each attachment and save it */ 
foreach($attachments as $attachment) 
{ 
    if($attachment['is_attachment'] == 1) 
    { 
     $filename = $overview[0]->subject; 
     if(empty($filename)) $filename = $attachment['filename']; 

     if(empty($filename)) $filename = time() . ".dat"; 

     /* prefix the email number to the filename in case two emails 
     * have the attachment with the same file name. 
     */ 
     $fp = fopen('./'.$holidex.'/'.$email_number."-".$filename, "w+"); 
     fwrite($fp, $attachment['attachment']); 
     fclose($fp); 
    } 

} 

Answer 1

使用pathinfo

$file_ext = ".".pathinfo($file['name'], PATHINFO_EXTENSION);

Answer 2

試試這個爆炸的文件名，並獲得擴展

$temp = explode(".", $attachment['filename']); 
$extension=end($temp);