/serv/www/site/insta_widgets

 $insta_widget_file=  $insta_widgets_path.$insta_widget_file;
 echo($insta_widget_file."=".(int)file_exists($insta_widget_file)."<br>");

/serv/www/site/insta_widgets/20190524_083904_insta.html=0
/serv/www/site/insta_widgets/20190523_045217_insta.html=0
/serv/www/site/insta_widgets/20190523_045238_insta.html=0

vi /serv/www/site/insta_widgets/20190524_083904_insta.html

 echo($insta_widget_file."=".(int)file_exists('/serv/www/site/insta_widgets/20190524_083904_insta.html')."<br>");

$ php -r "var_dump('/serv/www/site/insta_widgets/20190524_083904_insta.html');"
string(55) "/serv/www/site/insta_widgets/20190524_083904_insta.html"

function stripWhitespaces($string) {
  $old_string = $string;
  $string = strip_tags($string);
  $string = preg_replace('/([^\pL\pN\pP\pS\pZ])|([\xC2\xA0])/u', ' ', $string);
  $string = str_replace('  ',' ', $string);
  $string = trim($string);
  
  if ($string === $old_string) {
    return $string;
  } else {
    return stripWhitespaces($string); 
  }  
}