php让图片可以下载的方法
发布于 2014-10-04 11:16:18 | 102 次阅读 | 评论: 0 | 来源: 网友投递
PHP开源脚本语言PHP(外文名: Hypertext Preprocessor，中文名：“超文本预处理器”)是一种通用开源脚本语言。语法吸收了C语言、Java和Perl的特点，入门门槛较低，易于学习，使用广泛，主要适用于Web开发领域。PHP的文件后缀名为php。
本文是一个php实现的可以让图片也能像附件一样下载代码，感兴趣的同学参考下.
// 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/postscrīpt',
‘eps' => ‘application/postscrīpt',
‘ps' => ‘application/postscrīpt',
'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.wmlscrīptc',
‘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-javascrīpt',
'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.wmlscrīpt',
‘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',
);
?>
让图片也能像附件一样的下载，不多说了。请看下面的程序！
// 安全性过滤
$fileName = basename($_SERVER['QUERY_STRING']);
$filePath = dirname(__FILE__) . ‘/' . DL_DIR . $fileName;
/*
简述: DIRECTORY_SEPARATOR(目录界定符, 目录函数库预定义常量)
来源: Directory 目录函数(PHP手册->函数参考->Directories节点)
说明: windows系统下为反斜杠'', Linux系统下为'/',
windows下两个都正常用, linux就不知道了, 为了标准, 显得专业点, 嘿嘿.
*/
$filePath = str_replace(array(‘/', ‘\'), DIRECTORY_SEPARATOR, $filePath);
if(!is_file($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!');
}
}
?>
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