Encapsulation of PHP single file upload function

//Encapsulation of single file upload function
//Principle of file upload: Upload client files to the server, and then move the temporary files on the server to the specified directory.
//Direction of the file: Client -> Server (temporary file) -> Specify the directory. When the file enters the server, it becomes a temporary file. At this time, the name of the temporary file tmp_name should be used in the operation.
//It is unsafe to set upload file restrictions (file type and size) on the client because customers can modify the restrictions through source code, so set restrictions here on the server.
//Set encoding to UTF-8 to avoid Chinese garbled characters
header('Content-Type: text/html;charset=utf-8');
//Receive uploaded file information through $_FILES
$fileInfo = $ _FILES['myFile'];
function uploadFile($fileInfo,$uploadPath='uploads',$flag=true,$allowExt=array('jpeg','jpg','png','gif'),$maxSize = 2097152){
//Judge the error number, it can only be 0 or UPLOAD_ERR_OK, no error occurs, the upload is successful
 if($fileInfo['error']>0){
 //Attention! The error message is no 5
 switch($fileInfo['error']){
 case 1:
 $mes= 'The uploaded file exceeds the value of the upload_max_filesize option in the PHP configuration file';
 break;
 case 2:
 $mes= 'Exceeded the size of the HTML form MAX_FILE_SIZE limit';
 break;
 case 3:
 $mes= 'The file was partially uploaded';
 break;
 case 4:
 $mes= 'No option to upload the file';
 break;
 case 6:
 $mes= 'Temporary directory not found';
 break;
 case 7:
 $mes= 'File writing failed';
 break;
 case 8:
 $mes= 'The uploaded file was deleted by PHP Extension program break';
 break;

 }
 exit($mes);
 }
 $ext=pathinfo($fileInfo['name'],PATHINFO_EXTENSION);
 //$allowExt=array('jpeg',' jpg','png','gif');

 //Detect the type of uploaded file
 if(in_array($ext,$allowExt)){
 exit('illegal file type');
 }

 // Check whether the file size of the uploaded file meets the specification
 //$maxSize = 2097152;//2M
 if($fileInfo['size']>$maxSize){
 exit('The uploaded file is too large');
 }

 //Check whether the picture is a real picture type
 //$flag=true;
 if($flag){
 if(!getimagesize($fileInfo['tmp_name'])){
 exit('not a real picture Type');
 }
 }

 //Check whether it is uploaded through HTTP POST
 if(!is_uploaded_file($fileInfo['tmp_name'])){
 exit('The file is not uploaded through HTTP POST ');
 }

 //$uploadPath='uploads';
 //If there is no such folder, create one
 if(!file_exists($uploadPath)){
 mkdir( $uploadPath, 0777, true) ;
 chmod( $uploadPath, 0777 );
 }
 //The new file name is unique
 $uniName = md5 ( uniqid( microtime(true),true) ).'.'.$ext;
 $destination = $uploadPath. '/'.$uniName;
 //The @ symbol is to prevent customers from seeing error messages
 if(! @move_uploaded_file($fileInfo['tmp_name'], $destination )){
 exit('File move failed') ;
 }

 //echo 'File uploaded successfully';
 //return array(
 // 'newName'=>$destination,
 // 'size'=>$fileInfo['size'],
 // 'type'=>$fileInfo['type']
 //);
 return $destination;
}
?>

File upload, PHP