如何通过PHP脚本下载大文件

Question

使用PHP,我正在尝试提供大型文件(最多可能为200MB),由于授权问题,这些文件不在Web可访问目录中.目前,我使用一个readfile()调用以及一些标头来提供文件,但似乎PHP在发送之前将其加载到内存中.我打算在共享托管服务器上部署,这将不允许我使用大量内存或添加我自己的Apache模块,如X-Sendfile.

出于安全原因,我不能让我的文件位于Web可访问目录中.有没有人知道我可以在共享托管服务器上部署的内存密集度较低的方法？

编辑:

if(/* My authorization here */) {
        $path = "/uploads/";
        $name = $row[0];           //This is a MySQL reference with the filename
        $fullname = $path . $name; //Create filename
        $fd = fopen($fullname, "rb");
        if ($fd) {
            $fsize = filesize($fullname);
            $path_parts = pathinfo($fullname);
            $ext = strtolower($path_parts["extension"]);
            switch ($ext) {
                case "pdf":
                header("Content-type: application/pdf");
                break;
                case "zip":
                header("Content-type: application/zip");
                break;
                default:
                header("Content-type: application/octet-stream");
                break;
            }
            header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\"");
            header("Content-length: $fsize");
            header("Cache-control: private"); //use this to open files directly
            while(!feof($fd)) {
                $buffer = fread($fd, 1*(1024*1024));
                echo $buffer;
                ob_flush();
                flush();    //These two flush commands seem to have helped with performance
            }
        }
        else {
            echo "Error opening file";
        }
        fclose($fd);

Answer 1

如果您使用fopen而fread不是readfile,那应该可以解决您的问题.

PHP的文档中有一个解决方案,readfile展示了如何使用fread你想做的事情.

Answer 2

要从服务器下载大文件,我已经在php.ini文件中更改了以下设置:

Upload_max_filesize  - 1500 M
Max_input_time  - 1000
Memory_limit    - 640M
Max_execution_time -  1800
Post_max_size - 2000 M

现在,我可以在服务器上上传和下载175MB视频.既然如此,我有专用的服务器.因此,进行这些更改很容易.

下面是下载文件的PHP脚本.对于大文件大小,我没有对此代码段进行任何更改.

// Begin writing headers

            ob_clean(); // Clear any previously written headers in the output buffer

            if($filetype=='application/zip')
            {
                if(ini_get('zlib.output_compression'))
                    ini_set('zlib.output_compression', 'Off');
                $fp = @fopen($filepath, 'rb'); 
                if (strstr($_SERVER['HTTP_USER_AGENT'], "MSIE"))
                {
                    header('Content-Type: "$content_type"');
                    header('Content-Disposition: attachment; filename="'.$filename.'"');
                    header('Expires: 0');
                    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
                    header("Content-Transfer-Encoding: binary");
                    header('Pragma: public');
                    header("Content-Length: ".filesize(trim($filepath)));
                }
                else
                {
                    header('Content-Type: "$content_type"');
                    header('Content-Disposition: attachment; filename="'.$filename.'"');
                    header("Content-Transfer-Encoding: binary");
                    header('Expires: 0');
                    header('Pragma: no-cache');
                    header("Content-Length: ".filesize(trim($filepath)));
                }

                fpassthru($fp);
                fclose($fp);
            }
            elseif($filetype=='audio'|| $filetype=='video')
            { 
                global $mosConfig_absolute_path,$my;
                ob_clean();
                header("Pragma: public");
                header('Expires: 0');
                header('Cache-Control: no-store, no-cache, must-revalidate');
                header('Cache-Control: pre-check=0, post-check=0, max-age=0');
                header("Cache-Control: public");    
                header("Content-Description: File Transfer");
                header("Content-Type: application/force-download"); 
                header("Content-Type: $content_type");
                header("Content-Length: ".filesize(trim($filepath)));
                header("Content-Disposition: attachment; filename=\"$filename\"");
                // Force the download           
                header("Content-Transfer-Encoding: binary");            
                @readfile($filepath);
            }
              else{ // for all other types of files except zip,audio/video
                ob_clean();
                header("Pragma: public");
                header('Expires: 0');
                header('Cache-Control: no-store, no-cache, must-revalidate');
                header('Cache-Control: pre-check=0, post-check=0, max-age=0');
                header("Cache-Control: public");    
                header("Content-Description: File Transfer");
                header("Content-Type: $content_type");
                header("Content-Length: ".filesize(trim($filepath)));
                header("Content-Disposition: attachment; filename=\"$filename\"");
                // Force the download           
                header("Content-Transfer-Encoding: binary");            
                @readfile($filepath);       
            }
            exit;