使用PHP流式传输大文件

Question

我有一个200MB的文件，想通过下载提供给用户。但是，由于我们希望用户仅下载一次此文件，因此我们这样做：

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

强制下载。但是，这意味着整个文件必须加载到内存中，这通常不起作用。我们如何以每块kb的速度将文件流式传输给他们？

Answer 1

尝试这样的事情

<?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.';
}
?>