config.php

<?php
include "credentials.php";

$link = "";
$year = "";
$debug = false;

$aPathCdS                 = array(); // Array contenente i link della lista dei corsi di studio di ogni dipartimento;
$aPath_OPIS_Dipartimento  = array(); // Array contente i link delle schede opis del Dipartimento

$mysqli = new mysqli($host, $username, $password, $db_name);

if ($mysqli->connect_error)
    die('Errore di connessione');

$mysqli->query("DELETE FROM schede_opis");
$mysqli->query("DELETE FROM insegnamento");
$mysqli->query("DELETE FROM corso_di_studi");
$mysqli->query("DELETE FROM dipartimento");

function curl_exec_utf8($ch) {
  $data = curl_exec($ch);
  if (!is_string($data)) return $data;

  unset($charset);
  $content_type = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);

  /* 1: HTTP Content-Type: header */
  preg_match( '@([\w/+]+)(;\s*charset=(\S+))?@i', $content_type, $matches );
  if ( isset( $matches[3] ) )
      $charset = $matches[3];

  /* 2: <meta> element in the page */
  if (!isset($charset)) {
      preg_match( '@<meta\s+http-equiv="Content-Type"\s+content="([\w/]+)(;\s*charset=([^\s"]+))?@i', $data, $matches );
      if ( isset( $matches[3] ) ) {
          $charset = $matches[3];
          /* In case we want do do further processing downstream: */
          $data = preg_replace('@(<meta\s+http-equiv="Content-Type"\s+content="[\w/]+\s*;\s*charset=)([^\s"]+)@i', '$1utf-8', $data, 1);
      }
  }

  /* 3: <xml> element in the page */
  if (!isset($charset)) {
      preg_match( '@<\?xml.+encoding="([^\s"]+)@si', $data, $matches );
      if ( isset( $matches[1] ) ) {
          $charset = $matches[1];
          /* In case we want do do further processing downstream: */
          $data = preg_replace('@(<\?xml.+encoding=")([^\s"]+)@si', '$1utf-8', $data, 1);
      }
  }

  /* 4: PHP's heuristic detection */
  if (!isset($charset)) {
      $encoding = mb_detect_encoding($data);
      if ($encoding)
          $charset = $encoding;
  }

  /* 5: Default for HTML */
  if (!isset($charset)) {
      if (strstr($content_type, "text/html") === 0)
          $charset = "ISO 8859-1";
  }

  /* Convert it if it is anything but UTF-8 */
  /* You can change "UTF-8"  to "UTF-8//IGNORE" to
     ignore conversion errors and still output something reasonable */
  if (isset($charset) && strtoupper($charset) != "UTF-8")
      $data = iconv($charset, 'UTF-8', $data);

  return $data;
}

function getDOM($link)
{
    libxml_use_internal_errors(true);
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $link);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $html = curl_exec_utf8($ch);
    $html = utf8_encode($html);
    $dom  = new DOMDocument;
    $dom->substituteEntities = false;
    $dom->loadHTML('<?xml version="1.0" encoding="utf-8"?>' . $html);
    $dom->encoding = 'utf-8';
    curl_close($ch);
    return $dom;
}

function get_primary_id(int $unict_id, string $table): int {
  global $mysqli, $year;
  
  $result = $mysqli->query("SELECT id FROM $table WHERE unict_id = $unict_id AND anno_accademico = '$year'");
  while($row = $result->fetch_array(MYSQLI_ASSOC)) {
    return $row["id"];
  }

  echo "\nSELECT id FROM $table WHERE unict_id = $unict_id AND anno_accademico = '$year'";
  die("\n\nError getting the primary id of $table");
}
?>