时间：2021-07-01 10:21:17 帮助过：6人阅读
// 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', ); ?>
代码如下:
<?php
// 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!');
}
}
?>以上就是php让图片可以下载的代码_php技巧的内容，更多相关内容请关注PHP中文网（www.gxlcms.com）！