PHP readfile()向下载的文件中添加额外的字节 [英] PHP readfile() adding extra bytes to downloaded file

问题描述

我正在尝试解决从php脚本下载"zip"文件时遇到的问题.看来，当我使用以下代码下载文件时，下载的文件在文件的开头附加了一个额外的0A09，从而导致Winzip引发损坏错误.

<?php
$pagePermissions = 7;
require_once ('util/check.php');
require_once ('util/file_manager.php');

$file_manager = new FileManager();

if ($_SERVER['REQUEST_METHOD'] == "GET") {
if (isset($_GET['q']) && $_GET['q'] == 'logout') {
    //require_once ('util/users.php');
    //$userdata = new Userdata();
    $userdata -> kill_session();
    header("Location: download.php");
    exit ;
}

if (isset($_GET['q']) && $_GET['q'] == 'fetch') {
    if (isset($_GET['name'])) {
        @apache_setenv('no-gzip', 1); 
        header("Content-length: " . filesize('upload/' . $_GET['name'])); 
        header('Content-type: application/zip');
        //header("Content-Disposition: attachment; filename=\"{$_GET['name']}\" ");
        header("Content-Disposition: attachment; filename={$_GET['name']}");
        header('Content-Transfer-Encoding: binary');

        readfile('upload/' . $_GET['name']);
        exit();
    }
}

}
?>

任何帮助将不胜感激，通过直接链接可以很好地下载文件，仅通过此代码，会在文件开头附加2个字节. 预先感谢

解决方案

删除最后一个?>，并检查您的开始标记在脚本的第一个字符的第一行. PHP文件不必以结束标记结尾.您下载的文件包含一个(或多个)\r\n的原因是因为PHP将直接回显(输出)<?php ?>之外的任何内容.通常，如果您的脚本不回显HTML，则您将省略关闭的PHP标记，因为它不是强制性的，并且IMO会比其他任何事情带来更多麻烦.

** 编辑 **

如果您阅读 readfile 的PHP手册，有用的示例，您所遇到的问题中几乎所有的代码，少了两行代码:

@apache_setenv('no-gzip', 1); 
header("Content-length: " . filesize('upload/' . $_GET['name'])); 
header('Content-type: application/zip');
//header("Content-Disposition: attachment; filename=\"{$_GET['name']}\" ");
header("Content-Disposition: attachment; filename={$_GET['name']}");
header('Content-Transfer-Encoding: binary');

// add these two lines
ob_clean();   // discard any data in the output buffer (if possible)
flush();      // flush headers (if possible)

readfile('upload/' . $_GET['name']);
exit();

如果此后仍然有问题，则问题可能出在您的PHP代码上.

I am trying to troubleshoot an issue I am having with downloading a "zip" file from a php script. It seems that when I download the file using the following code, the downloaded file has an extra 0A09 appended to the beginning of the file, causing winzip to throw a corruption error.

<?php
$pagePermissions = 7;
require_once ('util/check.php');
require_once ('util/file_manager.php');

$file_manager = new FileManager();

if ($_SERVER['REQUEST_METHOD'] == "GET") {
if (isset($_GET['q']) && $_GET['q'] == 'logout') {
    //require_once ('util/users.php');
    //$userdata = new Userdata();
    $userdata -> kill_session();
    header("Location: download.php");
    exit ;
}

if (isset($_GET['q']) && $_GET['q'] == 'fetch') {
    if (isset($_GET['name'])) {
        @apache_setenv('no-gzip', 1); 
        header("Content-length: " . filesize('upload/' . $_GET['name'])); 
        header('Content-type: application/zip');
        //header("Content-Disposition: attachment; filename=\"{$_GET['name']}\" ");
        header("Content-Disposition: attachment; filename={$_GET['name']}");
        header('Content-Transfer-Encoding: binary');

        readfile('upload/' . $_GET['name']);
        exit();
    }
}

}
?>

Any help would be greatly appreciated, the file downloads fine through a direct link, the appended 2 bytes to the beginning of the file occurs only thorough this code. Thanks in advance

解决方案

Remove the last ?> and check that your opening tag is on the very first line, at the very first character of your scripts. PHP files do not have to end with end tags. The reason why your downloaded files contain a (or more) \r\n is because PHP will directly echo (output) anything outside of <?php ?>. Usually, if you script does not echo HTML, you will omit the closing PHP tag as it is not mandatory and, IMO, yields more trouble than anything else.

** Edit **

If you read the PHP manual for readfile, you have a useful example, pretty much the code you have in your question, less two lines of code :

@apache_setenv('no-gzip', 1); 
header("Content-length: " . filesize('upload/' . $_GET['name'])); 
header('Content-type: application/zip');
//header("Content-Disposition: attachment; filename=\"{$_GET['name']}\" ");
header("Content-Disposition: attachment; filename={$_GET['name']}");
header('Content-Transfer-Encoding: binary');

// add these two lines
ob_clean();   // discard any data in the output buffer (if possible)
flush();      // flush headers (if possible)

readfile('upload/' . $_GET['name']);
exit();

If you still have a problem after that, then the problem might not be with your PHP code.

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