PHP real-time generation and download of ultra-large data volumes of Excel files

//in addition, since Excel data is read from the database and then written to the output stream, it is necessary to set the execution time of PHP a bit longer//(default 30 seconds) Set_time_limit (0) does not limit PHP execution time.     Set_time_limit(0); $columns= [       ' Article ID ', ' article title ', ...//' OpenID '    ]; //processing data that needs to be exported    $timeStart=Strtotime(' 2018-08-08 00:00:00 '); $timeEnd=Strtotime(' 2018-08-08 23:59:59 '); $arr= db::table (' t_wechat_user_wx4ed9e1f4e0f3eeb0 ')->select (Db::raw (' distinct OpenID '))->where (' Subscribe_time ', ' >= ',$timeStart)->where (' Subscribe_time ', ' <= ',$timeEnd); $csvFileName= ' August 8 added fan openid.xlsx '; //set up to tell the browser to download the Excel file headers    Header(' Content-description:file Transfer '); Header(' Content-type:application/vnd.ms-excel '); Header(' Content-disposition:attachment; Filename= '.$csvFileName.‘"‘); Header(' expires:0 '); Header(' Cache-control:must-revalidate '); Header(' Pragma:public '); $fp=fopen(' Php://output ', ' a ');//Open output StreamMb_convert_variables (' GBK ', ' UTF-8 ',$columns); Fputcsv ($fp,$columns);//format the data in CSV format and write to the output stream    $accessNum=$arr-Count();//get the total from the database, assuming it's 1 million    $perSize= 1000;//number of bars per query    $pages=Ceil($accessNum/$perSize); $lastId= 0;  for($i= 1;$i<=$pages;$i++) {        //data that needs to be exported        $accessLog=$arr->offset ($lastId)->limit ($perSize)->get ([' OpenID '])ToArray (); foreach($accessLog  as $access) {            $rowData= [                ......//each row of data $access->openid            ]; Mb_convert_variables (' GBK ', ' UTF-8 ',$rowData); Fputcsv ($fp,$rowData); $lastId++; }        unset($accessLog);//release the memory of the variable//refresh output buffer to the browser        Ob_flush(); Flush();//You must use both the Ob_flush () and flush () functions to flush the output buffers.     }    fclose($fp); Exit();

Related real-time output:

① real-time output by setting

Ob_end_flush ();//Close cache
Ob_implicit_flush (TRUE);//True to turn on absolute swipe each time the cache is output equivalent to call flush () after each output
Header (' X-accel-buffering:no '); Turn off output caching

② real-time output via PHP syntax

$buffer = Ini_get (' output_buffering ');
Echo str_repeat (", $buffer + 1); Prevent browser caching
Ob_end_flush (); Turn off caching
for ($i =1; $i <=10; $i + +) {
Echo ' first ' $i. ' Secondary output. ' <br/>\n ";
Flush (); Refresh cache (send directly to browser)
Sleep (1);
}
echo ' output complete ';

PHP real-time generation and download of ultra-large data volumes of Excel files