今天从落伍弄到一个空间, 速度不错, 准备拿来放一些影音文件外链用, 因为每月流量限制10G, 所以不得不考虑百度和网友盗链的问题, 最后决定用PHP来读取文件, 易于控制.
写的过程中也让自己温习了些许知识. 突然想起当初入门的艰难, 觉得很有必要应该和大家分享下, 故有了下文, 希望对大家有帮助哈!
以上说的算是这篇文章的由头吧.
注:
1. 因为大部分内容手册都可以查询的到, 所以代码仅做了简要注释, 对于重要的知识点会用块注释讲解.
2. 主要代码取自Sablog1.6的attachment.php文件.
3. 讲解的代码已经剥离出来了, 可以正常使用.
4. 水平有限, 如有误请指正, 但千万别打击偶的积极性
- <?php
- // 文件目录
- define('DL_DIR', 'temp/');
- // 常见扩展名所对应的MIME类型
- $MIMETypes = array(
- 'ez' => 'application/andrew-inset',
- 'hqx' => 'application/mac-binhex40',
- 'cpt' => 'application/mac-compactpro',
- 'doc' => 'application/msword',
- 'bin' => 'application/octet-stream',
- 'dms' => 'application/octet-stream',
- 'lha' => 'application/octet-stream',
- 'lzh' => 'application/octet-stream',
- 'exe' => 'application/octet-stream',
- 'class' => 'application/octet-stream',
- 'so' => 'application/octet-stream',
- 'dll' => 'application/octet-stream',
- 'oda' => 'application/oda',
- 'pdf' => 'application/pdf',
- 'ai' => 'application/postscript',
- 'eps' => 'application/postscript',
- 'ps' => 'application/postscript',
- 'smi' => 'application/smil',
- 'smil' => 'application/smil',
- 'mif' => 'application/vnd.mif',
- 'xls' => 'application/vnd.ms-excel',
- 'ppt' => 'application/vnd.ms-powerpoint',
- 'wbxml' => 'application/vnd.wap.wbxml',
- 'wmlc' => 'application/vnd.wap.wmlc',
- 'wmlsc' => 'application/vnd.wap.wmlscriptc',
- 'bcpio' => 'application/x-bcpio',
- 'vcd' => 'application/x-cdlink',
- 'pgn' => 'application/x-chess-pgn',
- 'cpio' => 'application/x-cpio',
- 'csh' => 'application/x-csh',
- 'dcr' => 'application/x-director',
- 'dir' => 'application/x-director',
- 'dxr' => 'application/x-director',
- 'dvi' => 'application/x-dvi',
- 'spl' => 'application/x-futuresplash',
- 'gtar' => 'application/x-gtar',
- 'hdf' => 'application/x-hdf',
- 'js' => 'application/x-javascript',
- 'skp' => 'application/x-koan',
- 'skd' => 'application/x-koan',
- 'skt' => 'application/x-koan',
- 'skm' => 'application/x-koan',
- 'latex' => 'application/x-latex',
- 'nc' => 'application/x-netcdf',
- 'cdf' => 'application/x-netcdf',
- 'sh' => 'application/x-sh',
- 'shar' => 'application/x-shar',
- 'swf' => 'application/x-shockwave-flash',
- 'sit' => 'application/x-stuffit',
- 'sv4cpio' => 'application/x-sv4cpio',
- 'sv4crc' => 'application/x-sv4crc',
- 'tar' => 'application/x-tar',
- 'tcl' => 'application/x-tcl',
- 'tex' => 'application/x-tex',
- 'texinfo' => 'application/x-texinfo',
- 'texi' => 'application/x-texinfo',
- 't' => 'application/x-troff',
- 'tr' => 'application/x-troff',
- 'roff' => 'application/x-troff',
- 'man' => 'application/x-troff-man',
- 'me' => 'application/x-troff-me',
- 'ms' => 'application/x-troff-ms',
- 'ustar' => 'application/x-ustar',
- 'src' => 'application/x-wais-source',
- 'xhtml' => 'application/xhtml+xml',
- 'xht' => 'application/xhtml+xml',
- 'zip' => 'application/zip',
- 'au' => 'audio/basic',
- 'snd' => 'audio/basic',
- 'mid' => 'audio/midi',
- 'midi' => 'audio/midi',
- 'kar' => 'audio/midi',
- 'mpga' => 'audio/mpeg',
- 'mp2' => 'audio/mpeg',
- 'mp3' => 'audio/mpeg',
- 'aif' => 'audio/x-aiff',
- 'aiff' => 'audio/x-aiff',
- 'aifc' => 'audio/x-aiff',
- 'm3u' => 'audio/x-mpegurl',
- 'ram' => 'audio/x-pn-realaudio',
- 'rm' => 'audio/x-pn-realaudio',
- 'rpm' => 'audio/x-pn-realaudio-plugin',
- 'ra' => 'audio/x-realaudio',
- 'wav' => 'audio/x-wav',
- 'pdb' => 'chemical/x-pdb',
- 'xyz' => 'chemical/x-xyz',
- 'bmp' => 'image/bmp',
- 'gif' => 'image/gif',
- 'ief' => 'image/ief',
- 'jpeg' => 'image/jpeg',
- 'jpg' => 'image/jpeg',
- 'jpe' => 'image/jpeg',
- 'png' => 'image/png',
- 'tiff' => 'image/tiff',
- 'tif' => 'image/tiff',
- 'djvu' => 'image/vnd.djvu',
- 'djv' => 'image/vnd.djvu',
- 'wbmp' => 'image/vnd.wap.wbmp',
- 'ras' => 'image/x-cmu-raster',
- 'pnm' => 'image/x-portable-anymap',
- 'pbm' => 'image/x-portable-bitmap',
- 'pgm' => 'image/x-portable-graymap',
- 'ppm' => 'image/x-portable-pixmap',
- 'rgb' => 'image/x-rgb',
- 'xbm' => 'image/x-xbitmap',
- 'xpm' => 'image/x-xpixmap',
- 'xwd' => 'image/x-xwindowdump',
- 'igs' => 'model/iges',
- 'iges' => 'model/iges',
- 'msh' => 'model/mesh',
- 'mesh' => 'model/mesh',
- 'silo' => 'model/mesh',
- 'wrl' => 'model/vrml',
- 'vrml' => 'model/vrml',
- 'css' => 'text/css',
- 'html' => 'text/html',
- 'htm' => 'text/html',
- 'asc' => 'text/plain',
- 'txt' => 'text/plain',
- 'rtx' => 'text/richtext',
- 'rtf' => 'text/rtf',
- 'sgml' => 'text/sgml',
- 'sgm' => 'text/sgml',
- 'tsv' => 'text/tab-separated-values',
- 'wml' => 'text/vnd.wap.wml',
- 'wmls' => 'text/vnd.wap.wmlscript',
- 'etx' => 'text/x-setext',
- 'xsl' => 'text/xml',
- 'xml' => 'text/xml',
- 'mpeg' => 'video/mpeg',
- 'mpg' => 'video/mpeg',
- 'mpe' => 'video/mpeg',
- 'qt' => 'video/quicktime',
- 'mov' => 'video/quicktime',
- 'mxu' => 'video/vnd.mpegurl',
- 'avi' => 'video/x-msvideo',
- 'movie' => 'video/x-sgi-movie',
- 'ice' => 'x-conference/x-cooltalk',
- );
- // 安全性过滤
- $fileName = basename($_SERVER['QUERY_STRING']);
- $filePath = dirname(__FILE__) . '/' . DL_DIR . $fileName;
- if(!is_file($filePath)) {
- exit('File: ' . $fileName . ' not exists!');
- } else { // 如果是一个有效的文件
- // 文件扩展名
- $fileExt = substr(strrchr($fileName, '.'), 1);
- // 文件类型
- $fileType = $MIMETypes[$fileExt] ? $MIMETypes[$fileExt] : 'application/octet-stream';
- // 是否是图片
- $isImage = False;
- /*
- 简述: getimagesize(), 详见手册
- 说明: 判定某个文件是否为图片的有效手段, 常用在文件上传验证
- */
- $imgInfo = @getimagesize($filePath);
- if ($imgInfo[2] && $imgInfo['bits']) {
- $isImage = True;
- }
- // 显示方式
- $attachment = $isImage ? 'inline' : 'attachment';
- // 读取文件
- if (is_readable($filePath)) {
- /*
- 简述: ob_end_clean() 清空并关闭输出缓冲, 详见手册
- 说明: 关闭输出缓冲, 使文件片段内容读取至内存后即被送出, 减少资源消耗
- */
- ob_end_clean();
- /*
- HTTP头信息: 指示客户机可以接收生存期不大于指定时间(秒)的响应
- */
- header('Cache-control: max-age=31536000');
- /*
- HTTP头信息: 缓存文件过期时间(格林威治标准时)
- */
- header('Expires: ' . gmdate('D, d M Y H:i:s', time()+31536000) . ' GMT');
- /*
- HTTP头信息: 文件在服务期端最后被修改的时间
- Cache-control,Expires,Last-Modified 都是控制浏览器缓存的头信息
- 在一些访问量巨大的门户, 合理的设置缓存能够避免过多的服务器请求, 一定程度下缓解服务器的压力
- */
- header('Last-Modified: ' . gmdate('D, d M Y H:i:s' , filemtime($filePath) . ' GMT'));
- /*
- HTTP头信息: 文档的编码(Encode)方法, 因为附件请求的文件多样化, 改变编码方式有可能损坏文件, 故为none
- */
- header('Content-Encoding: none');
- /*
- HTTP头信息: 告诉浏览器当前请求的文件类型.
- 1.始终指定为application/octet-stream, 就代表文件是二进制流, 始终提示下载.
- 2.指定对应的类型, 如请求的是mp3文件, 对应的MIME类型是audio/mpeg, IE就会自动启动Windows Media Player进行播放.
- */
- header('Content-type: ' . $fileType);
- /*
- HTTP头信息: 如果为attachment, 则告诉浏览器, 在访问时弹出"文件下载"对话框, 并指定保存时文件的默认名称(可以与服务器的文件名不同)
- 如果要让浏览器直接显示内容, 则要指定为inline, 如图片, 文本
- */
- header('Content-Disposition: ' . $attachment . '; filename=' . $fileName);
- /*
- HTTP头信息: 告诉浏览器文件长度
- (IE下载文件的时候不是有文件大小信息么?)
- */
- header('Content-Length: ' . filesize($filePath));
- // 打开文件(二进制只读模式)
- $fp = fopen($filePath, 'rb');
- // 输出文件
- fpassthru($fp);
- // 关闭文件
- fclose($fp);
- exit();
- } else {
- exit('Read file failed!');
- }
- }
- ?>
相关资料:
1. http://java.ccidnet.com/art/3539/20070727/1157895_1.html
2. http://www.qqnote.com/article.asp?id=761
3. http://support.microsoft.com/kb/260519
最后要感谢热情帮助新手的朋友们, 感谢google. 
02.24 补充:
本文只是借用一个例子来说明用PHP做附件下载的实现方式,
基本思路即使用PHP读取某个目录下的文件,
而后通过操纵HTTP协议来实现"浏览器提示下载", 适用于任何格式的附件.

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