gistfile1.txt

public function mimeIsAmong( $error_msg )
    {
$r_conditions = array(
                                "image/png" ,
                                "image/jpg" ,
                                "image/jpeg" ,
                                "image/gif" ,
                                "application/pdf" ,
                                "application/msword" ,
                                "application/vnd.openxmlformats-officedocument.wordprocessingml.document" );
        $oFileInfo = new finfo ( FILEINFO_MIME_TYPE ) ;
        $sMimeType = $oFileInfo -> file ( "path/to/your/file") ;
        if ( ! in_array ( $sMimeType , $ar_conditions ) )
        {
            throw new \Exception("Someone is trying to upload an illegal file. Warn him!!");
        }
    }