PHP - 文件流问题

Question

我有一个包含下载部分的网站。我需要匿名用户不能直接访问这些文件，因此我将它们放在用户无法访问但 Web 服务器可以访问的目录中。当用户单击链接下载文件时，我需要它重定向到下载页面，该页面会将文件流式传输给用户，而无需用户知道目录或文件的位置，并且会要求他将其保存到自己的计算机上。我在上一篇文章中找到了以下代码，但我无法让它正常工作。可能是我不知道它想要传递给它的变量的正确名称。请附上如何使用您的代码的说明。

$filename='Firefox%20Setup%203.6.13.exe';
$file_path='http://ftp.byfly.by/pub/mozilla.org/firefox/releases/3.6.13/win32/fr';
$file= $file_path."/".$filename;
$len=filesize($file);
header("content-type: application/save");
header("content-length: $len");
header("content-disposition: attachment; filename=$filename");
$fp=fopen($file, "r");
fpassthru($fp);

Answer 1

我就是这样做的。

<?php

function getFile($file_location) {
    header('Content-Description: File Transfer');
    header('Content-type: application/exe');
    header('Content-Disposition: attachment; filename="supercoolFF.exe"');
    header('Content-Transfer-Encoding: binary');
    ob_end_clean();
    $url_info = parse_url($file_location);
    if (!isset($url_info['query'])) $url_info['query'] = '';
    $http = fsockopen($url_info['host'],$url_info['port']);
    $req = "GET " . $url_info['path'] . "?" . $url_info['query'] . " HTTP/1.1\r\n";
    $req .= "Host: " . $url_info['host'] . ":" . $url_info['port'] . "\r\n";
    $req .= "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n";
    $req .= "User-Agent  Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.8) Gecko/20100722 Firefox/3.6.8\r\n";
    $req .= "Accept-Language: en-us,en;q=0.5\r\n";
    $req .= "Accept-Encoding: gzip,deflate\r\n";
    $req .= "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\n";
    if ($len = strlen($url_info['query']) {
        $req .= 'Content-Length: ' . $len . "\r\n";
        $req .= "Connection: Close\r\n\r\n";
        $req .= $query . "\r\n\r\n";
    } else {
        $req .= "Connection: Keep-Alive\r\n\r\n";
    }
    fputs($http, $req);

    $content = "";
    $content_encountered = FALSE;
    ob_end_clean();
    while(strlen($part = fgets($http, 4096))) {
        if ($content_encountered) {
            echo $part;
            $content .= $part; 
        }
        if ($part == "\r\n") {
            $content_encountered = TRUE;
        }
    }
    fclose($http);
    exit;
}

$filename='Firefox%20Setup%203.6.13.exe?';
$file_path='http://ftp.byfly.by:80/pub/mozilla.org/firefox/releases/3.6.13/win32/fr';

getFile($file_path . '/' . $filename);

当然，最好先执行 HEAD 请求来获取文件大小并在响应中包含 Content-Length 标头，以便用户可以了解需要多长时间。或者，如果您始终要提供相同的文件，则可以对该数字进行硬编码。

Answer 2

假设您的目录中有一个名为“hiddenaccess”的文件，文件名为“test.mp3”，您可以在 php 变量中加载路径并让它进行下载

<?php
$file = "./hiddenaccess/test.mp3";
header("Content-Disposition: attachment; filename=" . urlencode($file));
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Description: File Transfer");             
header("Content-Length: " . filesize($file));

@readfile($file);

?>

注意：此文件中没有任何其他 echo 或 print 语句。

Answer 3

这是我（显然是其他人？！！？）开发的一个函数就是为了做到这一点，它是一个丰富的函数，但它检查并执行所有操作。虽然调用它很简单，但却是重要的部分。我在一个类中有这个函数，但你可以将它设为一个 php 函数，因为它没有依赖其他类函数。希望这对您有帮助。

   public static function output_file($path, $filename, $mime_type='') {

    $err = 'Sorry, the file you are requesting is unavailable.';

    $filename = rawurldecode($filename);

    // check that file exists and is readable
    if (file_exists($path) && is_readable($path)) {

        /* Figure out the MIME type (if not specified) */
        $known_mime_types=array(
         "pdf" => "application/pdf",
         "txt" => "text/plain",
         "html" => "text/html",
         "htm" => "text/html",
         "exe" => "application/octet-stream",
         "zip" => "application/zip",
         "doc" => "application/msword",
         "xls" => "application/vnd.ms-excel",
         "ppt" => "application/vnd.ms-powerpoint",
         "gif" => "image/gif",
         "png" => "image/png",
         "jpeg"=> "image/jpg",
         "jpg" =>  "image/jpg",
         "php" => "text/plain"
        );

        if($mime_type==''){
            $file_extension = strtolower(substr(strrchr($filename,"."),1));
            if(array_key_exists($file_extension, $known_mime_types)){
             $mime_type=$known_mime_types[$file_extension];
            } else {
             $mime_type="application/force-download";
            };
        };

        @ob_end_clean(); //turn off output buffering to decrease cpu usage

        if(ini_get('zlib.output_compression')) { //otherwise the filesize is way off
            ini_set('zlib.output_compression', 'Off');
        }

        // get the file size and send the http headers
        $size = filesize($path);
        header("Content-Type: $mime_type");
        header('Content-Disposition: attachment; filename="'.$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');

        // multipart-download and download resuming support
        if(isset($_SERVER['HTTP_RANGE'])) {

            list($a, $range) = explode("=", $_SERVER['HTTP_RANGE'], 2);
            list($range) = explode(",", $range, 2);
            list($range, $range_end) = explode("-", $range);

            $range=intval($range);

            if(!$range_end) {
                $range_end = $size-1;
            } else {
                $range_end = intval($range_end);
            }

            $new_length = $range_end-$range+1;

            header("HTTP/1.1 206 Partial Content");
            header("Content-Length: $new_length");
            header("Content-Range: bytes $range-$range_end/$size");
        } else {
            $new_length = $size;
            header("Content-Length: " . $size);
        }

        /* output the file itself */
        $chunksize = 1*(1024*1024); //may want to change this
        $bytes_send = 0;

        if ($file = fopen($path, 'r')) {
            if(isset($_SERVER['HTTP_RANGE'])) {
                fseek($file, $range);
            }

            while(!feof($file) && (!connection_aborted()) && ($bytes_send<$new_length)) {
                $buffer = fread($file, $chunksize);
                print($buffer); //echo($buffer); // is also possible
                flush();
                $bytes_send += strlen($buffer);
            }

            fclose($file);

        } else {
            die($err);
        }

    } else {

        die($err);

    }

    die();
}

使用它会是这样的。

$path = '/var/www/site/httpdocs/upload/private/myfile.txt';
$dl_filename = 'NDA_'.time();
$mime_type = 'doc';
output_file($path,$dl_filename,$mime_type);