下载PDF php

Question

我正在尝试强制下载pdf文件。我已经在堆栈上看到了几个有关此问题的问题。但是当应用时，解决方案对我来说似乎不起作用。

输出后的PDF文件（使用FPDF）可以保存并直接在服务器上查看，但是当我下载或通过电子邮件发送文件时，它显示为已损坏。

有人可以提供建议吗？

下载或发送电子邮件的代码（取决于所需的操作）

$pdf->output(ROOTDIR.'/modules/addons/statement_generator/reports/statement.pdf');
    if($action=='print'){
        $file_name = 'statement.pdf';
        $file_url = "http://".$_SERVER['SERVER_NAME']."/modules/addons/statement_generator/reports/" . $file_name;
        header('Content-Type: application/pdf');
        header("Content-Transfer-Encoding: Binary"); 
        header("Content-disposition: attachment; filename=\"".$file_name."\""); 
        readfile($file_url);
        return('Statement Generated. Starting download.');
        exit;
    }elseif($action=='mail'){
        require_once(ROOTDIR."/modules/addons/statement_generator/PHPMailer_5.2.0/class.phpmailer.php");

        $mail = new PHPMailer();

        $mail->IsSMTP();                                      // set mailer to use SMTP
        $mail->Host = "localhost";  // specify main and backup server
        $mail->SMTPAuth = false;     // turn on SMTP authentication
        $mail->Username = "";  // SMTP username
        $mail->Password = ""; // SMTP password

        $mail->From = $from_mail;
        $mail->FromName = $from_name;
        $mail->AddAddress($client_email, $name);                 // name is optional
        $mail->AddReplyTo($from_mail, $from_name);

        $mail->WordWrap = 50;                                 // set word wrap to 50 characters
        //$mail->AddAttachment(ROOTDIR.'/modules/addons/statement_generator/reports/statement.pdf');         // add attachments
        $mail->AddAttachment(ROOTDIR.'/modules/addons/statement_generator/reports/statement.pdf', "Statement.pdf");    // optional name
        $mail->IsHTML(true);                                  // set email format to HTML

        $mail->Subject = $subject;
        $mail->Body    = $body;
        $mail->AltBody = $non_html_body;

        if(!$mail->Send())
        {
           return( "Message could not be sent. <p>"."Mailer Error: " . $mail->ErrorInfo);
           exit;
        }

        return( "Message has been sent");
    }