PHP下载大文件

 1 <?php
 2             $realname = "xxx.pdf";
 3             $filename = "xxx.pdf";
 4             set_time_limit(0);
 5             $filesize = filesize($realname);
 6             header(‘Content-Description: File Transfer‘);
 7             header(‘Content-Type: application/octet-stream‘);
 8             header(‘Content-Transfer-Encoding: binary‘);
 9             header(‘Accept-Ranges: bytes‘);
10             header(‘Expires: 0‘);
11             header(‘Cache-Control: must-revalidate‘);
12             header(‘Pragma: public‘);
13             header(‘Content-Length: ‘ . $filesize);
14             header(‘Content-Disposition: attachment; filename=‘ . $filename);
15 
16             // 打开文件
17             $fp = fopen($realname, ‘rb‘);
18             // 设置指针位置
19             fseek($fp, 0);
20 
21             // 开启缓冲区
22             ob_start();
23             // 分段读取文件
24             while (!feof($fp)) {
25                 $chunk_size = 1024 * 8; // 8kb
26                 echo fread($fp, $chunk_size);
27                 ob_flush(); // 刷新PHP缓冲区到Web服务器
28                 flush(); // 刷新Web服务器缓冲区到浏览器
29                 sleep(1); // 每1秒 下载 8 KB
30             }
31             // 关闭缓冲区
32             ob_end_clean();
33 
34             fclose($fp);       

<?php
            $realname = "xxx.pdf";
            $filename = "xxx.pdf";
            set_time_limit(0);
            $filesize = filesize($realname);
            header(‘Content-Description: File Transfer‘);
            header(‘Content-Type: application/octet-stream‘);
            header(‘Content-Transfer-Encoding: binary‘);
            header(‘Accept-Ranges: bytes‘);
            header(‘Expires: 0‘);
            header(‘Cache-Control: must-revalidate, post-check=0, pre-check=0‘);
            header(‘Pragma: public‘);
            header(‘Content-Length: ‘ . $filesize);
            header(‘Content-Disposition: attachment; filename=‘ . $filename);

            // 打开文件
            $fp = fopen($realname, ‘rb‘);
            ob_clean();
            ob_end_flush();
            while (!feof($fp)) {
                echo fread($fp, $filesize);
                ob_flush(); // 刷新PHP缓冲区到Web服务器
                flush(); // 刷新Web服务器缓冲区到浏览器
            }

            fclose($fp);
            exit;