php讓圖片可以下載的方法

發布于 2014-10-04 11:16:18 | 102 次閱讀 | 評論: 0 | 來源: 網友投遞

PHP開源腳本語言PHP(外文名: Hypertext Preprocessor，中文名：“超文本預處理器”)是一種通用開源腳本語言。語法吸收了C語言、Java和Perl的特點，入門門檻較低，易于學習，使用廣泛，主要適用于Web開發領域。PHP的文件后綴名為php。

本文是一個php實現的可以讓圖片也能像附件一樣下載代碼，感興趣的同學參考下.

// 文件目錄

define(‘DL_DIR', ‘temp/');

// 常見擴展名所對應的MIME類型

$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',

);

?>

讓圖片也能像附件一樣的下載，不多說了。請看下面的程序！

// 安全性過濾

$fileName = basename($_SERVER['QUERY_STRING']);

$filePath = dirname(__FILE__) . ‘/' . DL_DIR . $fileName;

/*

簡述: DIRECTORY_SEPARATOR(目錄界定符, 目錄函數庫預定義常量)

來源: Directory 目錄函數(PHP手冊->函數參考->Directories節點)

說明: windows系統下為反斜杠'', Linux系統下為'/',

windows下兩個都正常用, linux就不知道了, 為了標準, 顯得專業點, 嘿嘿.

*/

$filePath = str_replace(array(‘/', ‘\'), DIRECTORY_SEPARATOR, $filePath);

if(!is_file($filePath)) {

exit(‘File: ' . $fileName . ‘ not exists!');

} else { // 如果是一個有效的文件

// 文件擴展名

$fileExt = substr(strrchr($fileName, ‘.'), 1);

// 文件類型

$fileType = $MIMETypes[$fileExt] ? $MIMETypes[$fileExt] : ‘application/octet-stream';

// 是否是圖片

$isImage = False;

/*

簡述: getimagesize(), 詳見手冊

說明: 判定某個文件是否為圖片的有效手段, 常用在文件上傳驗證

*/

$imgInfo = @getimagesize($filePath);

if ($imgInfo[2] && $imgInfo['bits']) {

$isImage = True;

}

// 顯示方式

$attachment = $isImage ? ‘inline' : ‘attachment';

// 讀取文件

if (is_readable($filePath)) {

/*

簡述: ob_end_clean() 清空并關閉輸出緩沖, 詳見手冊

說明: 關閉輸出緩沖, 使文件片段內容讀取至內存后即被送出, 減少資源消耗

*/

ob_end_clean();

/*

HTTP頭信息: 指示客戶機可以接收生存期不大于指定時間(秒)的響應

*/

header(‘Cache-control: max-age=31536000′);

/*

HTTP頭信息: 緩存文件過期時間(格林威治標準時)

*/

header(‘Expires: ' . gmdate(‘D, d M Y H:i:s', time()+31536000) . ‘ GMT');

/*

HTTP頭信息: 文件在服務期端最后被修改的時間

Cache-control,Expires,Last-Modified 都是控制瀏覽器緩存的頭信息

在一些訪問量巨大的門戶, 合理的設置緩存能夠避免過多的服務器請求, 一定程度下緩解服務器的壓力

*/

header(‘Last-Modified: ' . gmdate(‘D, d M Y H:i:s' , filemtime($filePath) . ‘ GMT'));

/*

HTTP頭信息: 文檔的編碼(Encode)方法, 因為附件請求的文件多樣化, 改變編碼方式有可能損壞文件, 故為none

*/

header(‘Content-Encoding: none');

/*

HTTP頭信息: 告訴瀏覽器當前請求的文件類型.

1.始終指定為application/octet-stream, 就代表文件是二進制流, 始終提示下載.

2.指定對應的類型, 如請求的是mp3文件, 對應的MIME類型是audio/mpeg, IE就會自動啟動Windows Media Player進行播放.

*/

header(‘Content-type: ' . $fileType);

/*

HTTP頭信息: 如果為attachment, 則告訴瀏覽器, 在訪問時彈出”文件下載”對話框, 并指定保存時文件的默認名稱(可以與服務器的文件名不同)

如果要讓瀏覽器直接顯示內容, 則要指定為inline, 如圖片, 文本

*/

header(‘Content-Disposition: ' . $attachment . ‘; filename=' . $fileName);

/*

HTTP頭信息: 告訴瀏覽器文件長度

(IE下載文件的時候不是有文件大小信息么?)

*/

header(‘Content-Length: ' . filesize($filePath));

// 打開文件(二進制只讀模式)

$fp = fopen($filePath, ‘rb');

// 輸出文件

fpassthru($fp);

// 關閉文件

fclose($fp);

exit();

} else {

exit(‘Read file failed!');

}

}

?>

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