别人讨论的



原文地址：http://pastie.org/3848723



源码如下：

<?php



/**

 * 从 Ruby On Rails 迁移到 PHP 的 send_file() 方法

 * 参见：http://api.rubyonrails.org/classes/ActionController/DataStreaming.html#method-i-send_file

 */

function send_file($path, $options = array()) {

    if (! is_file($path) || ! is_readable($path)) {

        throw new Exception("没有找到指定的文件");

    }



    if (! isset($options['x_sendfile'])) {

        $options['x_sendfile'] = TRUE;

    }



    if (! isset($options['filename']) && ! isset($options['url_base_filename'])) {

        $options['filename'] = basename($path);

    }



    $defaults = array(

        'type' => 'application/octet-stream',

        'disposition' => 'attachment'

    );

    $options = array_merge($defaults, $options);



    foreach (array('type', 'disposition') as $arg) {

        if (is_null($options[$arg])) {

            throw new InvalidArgumentException("{$arg} option required");

        }

    }



    $disposition = $options['disposition'];

    if (isset($options['filename'])) {

        if (preg_match("/MSIE/", $_SERVER["HTTP_USER_AGENT"])) {

            $encoded_filename = str_replace("+", "%20", urlencode($options['filename']));

            $disposition .= "; filename=\"{$encoded_filename }\"";

        } else {

            $disposition .= "; filename=\"{$options['filename']}\"";

        }

    }



    if (! headers_sent()) {

        header("Content-Type: {$options['type']}");

        header("Content-Disposition: {$disposition}");

        header("Content-Transfer-Encoding: binary");

    }



    $x_sendfile_supported = $options['x_sendfile'] && in_array('mod_xsendfile', apache_get_modules());

    if (! headers_sent() && $x_sendfile_supported) {

        header("X-Sendfile: {$path}");

    } else {

        @readfile($path);

    }

}