使用PHP流式传输大型文件

Question

我有一个200MB的文件,我想通过下载给用户.但是,由于我们希望用户只下载一次该文件,我们这样做:

echo file_get_contents('http://some.secret.location.com/secretfolder/the_file.tar.gz');

强制下载.但是,这意味着必须将整个文件加载到内存中,这通常不起作用.我们怎样才能将这个文件传输给它们,每块大约kb？

Answer 1

尝试这样的事情(来源http://teddy.fr/2007/11/28/how-serve-big-files-through-php/):

<?php
define('CHUNK_SIZE', 1024*1024); // Size (in bytes) of tiles chunk

// Read a file and display its content chunk by chunk
function readfile_chunked($filename, $retbytes = TRUE) {
    $buffer = '';
    $cnt    = 0;
    $handle = fopen($filename, 'rb');

    if ($handle === false) {
        return false;
    }

    while (!feof($handle)) {
        $buffer = fread($handle, CHUNK_SIZE);
        echo $buffer;
        ob_flush();
        flush();

        if ($retbytes) {
            $cnt += strlen($buffer);
        }
    }

    $status = fclose($handle);

    if ($retbytes && $status) {
        return $cnt; // return num. bytes delivered like readfile() does.
    }

    return $status;
}

// Here goes your code for checking that the user is logged in
// ...
// ...

if ($logged_in) {
    $filename = 'path/to/your/file';
    $mimetype = 'mime/type';
    header('Content-Type: '.$mimetype );
    readfile_chunked($filename);

} else {
    echo 'Tabatha says you haven\'t paid.';
}
?>

Answer 2

使用fpassthru().顾名思义,它不会在发送之前将整个文件读入内存,而是直接将其输出到客户端.

从手册中的示例修改:

<?php

// the file you want to send
$path = "path/to/file";

// the file name of the download, change this if needed
$public_name = basename($path);

// get the file's mime type to send the correct content type header
$finfo = finfo_open(FILEINFO_MIME_TYPE);
$mime_type = finfo_file($finfo, $path);

// send the headers
header("Content-Disposition: attachment; filename=$public_name;");
header("Content-Type: $mime_type");
header('Content-Length: ' . filesize($path));

// stream the file
$fp = fopen($path, 'rb');
fpassthru($fp);
exit;

如果您希望将内容直接流式传输到浏览器而不是下载(如果浏览器支持内容类型,如视频,音频,PDF等),则删除Content-Disposition标头.

Answer 3

看一下手册页中的示例fsockopen():

$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />\n";
} else {
    $out = "GET / HTTP/1.1\r\n";
    $out .= "Host: www.example.com\r\n";
    $out .= "Connection: Close\r\n\r\n";
    fwrite($fp, $out);
    while (!feof($fp)) {
        echo fgets($fp, 128);
    }
    fclose($fp);
}

这将连接到www.example.com,发送请求然后获取并以128字节块的形式回应响应.您可能希望使其超过128个字节.

Answer 4

我在http://codesamplez.com/programming/php-html5-video-streaming-tutorial中找到了这种方法

它对我来说非常好

   <?php

class VideoStream
{
    private $path = "";
    private $stream = "";
    private $buffer = 102400;
    private $start  = -1;
    private $end    = -1;
    private $size   = 0;

    function __construct($filePath) 
    {
        $this->path = $filePath;
    }

    /**
     * Open stream
     */
    private function open()
    {
        if (!($this->stream = fopen($this->path, 'rb'))) {
            die('Could not open stream for reading');
        }

    }

    /**
     * Set proper header to serve the video content
     */
    private function setHeader()
    {
        ob_get_clean();
        header("Content-Type: video/mp4");
        header("Cache-Control: max-age=2592000, public");
        header("Expires: ".gmdate('D, d M Y H:i:s', time()+2592000) . ' GMT');
        header("Last-Modified: ".gmdate('D, d M Y H:i:s', @filemtime($this->path)) . ' GMT' );
        $this->start = 0;
        $this->size  = filesize($this->path);
        $this->end   = $this->size - 1;
        header("Accept-Ranges: 0-".$this->end);

        if (isset($_SERVER['HTTP_RANGE'])) {

            $c_start = $this->start;
            $c_end = $this->end;

            list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
            if (strpos($range, ',') !== false) {
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $this->start-$this->end/$this->size");
                exit;
            }
            if ($range == '-') {
                $c_start = $this->size - substr($range, 1);
            }else{
                $range = explode('-', $range);
                $c_start = $range[0];

                $c_end = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $c_end;
            }
            $c_end = ($c_end > $this->end) ? $this->end : $c_end;
            if ($c_start > $c_end || $c_start > $this->size - 1 || $c_end >= $this->size) {
                header('HTTP/1.1 416 Requested Range Not Satisfiable');
                header("Content-Range: bytes $this->start-$this->end/$this->size");
                exit;
            }
            $this->start = $c_start;
            $this->end = $c_end;
            $length = $this->end - $this->start + 1;
            fseek($this->stream, $this->start);
            header('HTTP/1.1 206 Partial Content');
            header("Content-Length: ".$length);
            header("Content-Range: bytes $this->start-$this->end/".$this->size);
        }
        else
        {
            header("Content-Length: ".$this->size);
        }  

    }

    /**
     * close curretly opened stream
     */
    private function end()
    {
        fclose($this->stream);
        exit;
    }

    /**
     * perform the streaming of calculated range
     */
    private function stream()
    {
        $i = $this->start;
        set_time_limit(0);
        while(!feof($this->stream) && $i <= $this->end) {
            $bytesToRead = $this->buffer;
            if(($i+$bytesToRead) > $this->end) {
                $bytesToRead = $this->end - $i + 1;
            }
            $data = fread($this->stream, $bytesToRead);
            echo $data;
            flush();
            $i += $bytesToRead;
        }
    }

    /**
     * Start streaming video content
     */
    function start()
    {
        $this->open();
        $this->setHeader();
        $this->stream();
        $this->end();
    }
}

要使用此类,您必须编写如下的简单代码:

$stream = new VideoStream($filePath);
$stream->start();

Answer 5

我也遇到了这个问题，使用 readfile() 强制下载。内存问题不在于读取文件，而在于输出缓冲。

只要确保在读取文件之前关闭输出缓冲，问题就应该得到解决。

if (ob_get_level()) ob_end_clean();
readfile($yourfile);

适用于大小远大于分配的内存限制的文件。