强制下载脚本 [英] force download script

问题描述

我编写了一个不错的强制下载文件"脚本，目的是确保无论文件是什么类型，都可以下载文件而不是显示在浏览器中.

I worked on a nice "force download file" script which purpose is to make sure files are being offered to download instead of displayed in the browser, no matter what type of file that is.

它曾经运行良好，但最近我收到反馈说它不起作用，特别是对于 pdf 和 xls 文件(MS Excel).在 PDF 的情况下，该文件要么被检测为无效"，要么在 xls 文件的情况下，将 html 文件目录页面的一部分置于其内容之上.

It used to work well but recently i received feedback that it wouldn't work, notably for pdf and xls files (MS Excel). The file is either detected as "invalid" in the case of the PDF, or gets part of the html file directory page on top of its content in the case of the xls file.

我的函数到底有什么问题?

What is wrong exactly with my function?

给了.请注意，它可以使用 url 或本地路径.

Here it is. Note that it can work either with a url or a local path.

    function offerToDownloadFile($filename, $access_type='url') {
    /*
    PHP FORCE DOWNLOAD SCRIPT
    */

    // required for IE, otherwise Content-disposition is ignored
        if (ini_get('zlib.output_compression'))
            ini_set('zlib.output_compression', 'Off');

        if($access_type === 'url') {
        // access type is via the file 's url
            $parsed_url = parse_url($filename);
            $fileinfo = pathinfo($filename);
            $parsed_url['extension'] = $fileinfo['extension'];
            $parsed_url['filename'] = $fileinfo['basename'];
            $parsed_url['localpath'] = LOCALROOT . $parsed_url['path'];
        }
        else {
        // access type is the local file path
            $fileinfo = pathinfo($filename);
            $parsed_url['localpath'] = $filename;
            $parsed_url['filename'] = basename($filename);
            $parsed_url['extension'] = $fileinfo['extension'];
        }


        // just in case there is a double slash created when joining document_root and path
        $parsed_url['localpath'] = preg_replace('/\/\//', '/', $parsed_url['localpath']);

        if (!file_exists($parsed_url['localpath'])) {
            die('File not found: ' . $parsed_url['localpath']);
        }
        $allowed_ext = array('ics','pdf', 'png', 'jpg', 'jpeg', 'zip', 'doc', 'xls', 'gif', 'exe', 'ppt','ai','psd','odt');
        if (!in_array($parsed_url['extension'], $allowed_ext)) {
            die('This file type is forbidden.');
        }

        switch ($parsed_url['extension']) {
            case "ics": $ctype="text/calendar";
                break;
            case "pdf": $ctype = "application/pdf";
                break;
            case "exe": $ctype = "application/octet-stream";
                break;
            case "zip": $ctype = "application/zip";
                break;
            case "doc": $ctype = "application/msword";
                break;
            case "xls": 
                $ctype = "application/vnd.ms-excel";
                break;
            case "ppt": $ctype = "application/vnd.ms-powerpoint";
                break;
            case "gif": $ctype = "image/gif";
                break;
            case "png": $ctype = "image/png";
                break;
            case "jpeg":
            case "jpg": $ctype = "image/jpg";
                break;
            default: $ctype = "application/force-download";
        }
        header("Pragma: public"); // required
        header("Expires: 0");
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header("Cache-Control: private", false); // required for certain browsers
        header("Content-Type: $ctype");
        header("Content-Disposition: attachment; filename=\"" . $parsed_url['filename'] . "\";");
        header("Content-Transfer-Encoding: binary");
        //  header("Content-Length: " . filesize($parsed_url['localpath']));
        readfile($parsed_url['localpath']);
        clearstatcache();
        die();
        exit();
    }

推荐答案

脚本现在可以工作了.我不得不改用这个 header() 调用.我真的不知道为什么，这是反复试验导致我找到这个解决方案的原因.

The script now works. I had to make this header() calls instead. I don't really know why, it's trial and error that led me to this solution.

header("Content-Type: $ctype");
header("Content-Disposition: attachment; filename=\"" . $parsed_url['filename'] . "\";");
header("Content-Transfer-Encoding: binary");
header('Accept-Ranges: bytes');
header("Cache-control: private");
header('Pragma: private');
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

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