Php large file download program [http cache negotiation, Etag tag, resumable upload]

<? Php tutorial

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

003

004 // usage

005 downFile ($ file_path );

006

007 // Server File Path, download file name (default: Server File name), permit user download method (optional by default), speed limit (automatically by default), file type (default: All)

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']) <$ lastModified)

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 <0? 0: $ startPos;

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

081

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

083

084 if ($ length <0)

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 <$ contentLength &&! Feof ($ fp) & connection_status () = 0)

132 {

133 if ($ speedLimit! = 0)

134 {

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

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

137}

138

139 $ readBufferSize = $ contentLength-$ bytesSent <$ bufferSize? $ ContentLength-$ bytesSent: $ bufferSize;

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

141

142 echo $ buffer;

143

144 maid ();

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?>