//执行
$command = "python3.8 /data/sites/webs/python_script/pdf_to_img.py $upload_dir"."$name $uid 2>&1";
$pid = popen($command,"r");
while( !feof( $pid ) ) {
echo fread($pid, 256);
flush();
ob_flush();
usleep(100000);
}
pclose($pid);