欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  php教程

php 超大文件下载程序[http 缓存协商,Etag标记,断点续传]

程序员文章站 2022-03-15 20:06:09
...

002 $file_path = './download/download_cn.rar';

003

004 //使用方法

005 downFile($file_path);

006

007 // 服务器文件路径,下载文件名字(默认为服务器文件名),是否许可用户下载方式(默认可选),速度限制(默认自动),文件类型(默认所有)

008 function downFile($fileName, $fancyName = '', $forceDownload = true, $speedLimit = 0, $contentType = '') {

009 if (!is_readable($fileName))

010 {

011 header("HTTP/1.1 404 Not Found");

012 return false;

013 }

014

015 $fileStat = stat($fileName);

016 $lastModified = $fileStat['mtime'];

017

018 $md5 = md5($fileStat['mtime'] .'='. $fileStat['ino'] .'='. $fileStat['size']);

019 $etag = '"' . $md5 . '-' . crc32($md5) . '"';

020

021 header('Last-Modified: ' . gmdate("D, d M Y H:i:s", $lastModified) . ' GMT');

022 header("ETag: $etag");

023

024 if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= $lastModified)

025 {

026 header("HTTP/1.1 304 Not Modified");

027 return true;

028 }

029

030 if (isset($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_UNMODIFIED_SINCE'])

031 {

032 header("HTTP/1.1 304 Not Modified");

033 return true;

034 }

035

036 if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && $_SERVER['HTTP_IF_NONE_MATCH'] == $etag)

037 {

038 header("HTTP/1.1 304 Not Modified");

039 return true;

040 }

041

042 if ($fancyName == '')

043 {

044 $fancyName = basename($fileName);

045 }

046

047 if ($contentType == '')

048 {

049 $contentType = 'application/octet-stream';

050 }

051

052 $fileSize = $fileStat['size'];

053

054 $contentLength = $fileSize;

055 $isPartial = false;

056

057 if (isset($_SERVER['HTTP_RANGE']))

058 {

059 if (preg_match('/^bytes=(d*)-(d*)$/', $_SERVER['HTTP_RANGE'], $matches))

060 {

061 $startPos = $matches[1];

062 $endPos = $matches[2];

063

064 if ($startPos == '' && $endPos == '')

065 {

066 return false;

067 }

068

069 if ($startPos == '')

070 {

071 $startPos = $fileSize - $endPos;

072 $endPos = $fileSize - 1;

073 }

074 else if ($endPos == '')

075 {

076 $endPos = $fileSize - 1;

077 }

078

079 $startPos = $startPos

080 $endPos = $endPos > $fileSize - 1 ? $fileSize - 1 : $endPos;

081

082 $length = $endPos - $startPos + 1;

083

084 if ($length

085 {

086 return false;

087 }

088

089 $contentLength = $length;

090 $isPartial = true;

091 }

092 }

093

094 // send headers

095 if ($isPartial)

096 {

097 header('HTTP/1.1 206 Partial Content');

098 header("Content-Range: bytes $startPos-$endPos/$fileSize");

099

100 }

101 else

102 {

103 header("HTTP/1.1 200 OK");

104 $startPos = 0;

105 $endPos = $contentLength - 1;

106 }

107

108 header('Pragma: cache');

109 header('Cache-Control: public, must-revalidate, max-age=0');

110 header('Accept-Ranges: bytes');

111 header('Content-type: ' . $contentType);

112 header('Content-Length: ' . $contentLength);

113

114 if ($forceDownload)

115 {

116 header('Content-Disposition: attachment; filename="' . rawurlencode($fancyName). '"');

117 }

118

119 header("Content-Transfer-Encoding: binary");

120

121 $bufferSize = 2048;

122

123 if ($speedLimit != 0)

124 {

125 $packetTime = floor($bufferSize * 1000000 / $speedLimit);

126 }

127

128 $bytesSent = 0;

129 $fp = fopen($fileName, "rb");

130 fseek($fp, $startPos);

131 while ($bytesSent

132 {

133 if ($speedLimit != 0)

134 {

135 list($usec, $sec) = explode(" ", microtime());

136 $outputTimeStart = ((float)$usec + (float)$sec);

137 }

138

139 $readBufferSize = $contentLength - $bytesSent

140 $buffer = fread($fp, $readBufferSize);

141

142 echo $buffer;

143

144 ob_flush();

145 flush();

146

147 $bytesSent += $readBufferSize;

148

149 if ($speedLimit != 0)

150 {

151 list($usec, $sec) = explode(" ", microtime());

152 $outputTimeEnd = ((float)$usec + (float)$sec);

153

154 $useTime = ((float) $outputTimeEnd - (float) $outputTimeStart) * 1000000;

155 $sleepTime = round($packetTime - $useTime);

156 if ($sleepTime > 0)

157 {

158 usleep($sleepTime);

159 }

160 }

161 }

162 return true;

163 }

164 ?>