+ if (empty($items)) {
+ yield [];
+ }
+ $subArray = array_pop($items);
+ if (empty($subArray)) {
+ return;
+ }
+ foreach (cartesian_product_generator($items) as $item) {
+ foreach ($subArray as $value) {
+ yield $item + [count($item) => $value];
+ }
+ }
+}
+
+/**
+ * Generates a default API secret.
+ *
+ * Note that the random-ish methods used in this function are predictable,
+ * which makes them NOT suitable for crypto.
+ * BUT the random string is salted with the salt and hashed with the username.
+ * It makes the generated API secret secured enough for Shaarli.
+ *
+ * PHP 7 provides random_int(), designed for cryptography.
+ * More info: http://stackoverflow.com/questions/4356289/php-random-string-generator
+
+ * @param string $username Shaarli login username
+ * @param string $salt Shaarli password hash salt
+ *
+ * @return string|bool Generated API secret, 12 char length.
+ * Or false if invalid parameters are provided (which will make the API unusable).
+ */
+function generate_api_secret($username, $salt)
+{
+ if (empty($username) || empty($salt)) {
+ return false;
+ }
+
+ return str_shuffle(substr(hash_hmac('sha512', uniqid($salt), $username), 10, 12));
+}
+
+/**
+ * Trim string, replace sequences of whitespaces by a single space.
+ * PHP equivalent to `normalize-space` XSLT function.
+ *
+ * @param string $string Input string.
+ *
+ * @return mixed Normalized string.
+ */
+function normalize_spaces($string)
+{
+ return preg_replace('/\s{2,}/', ' ', trim($string));
+}
+
+/**
+ * Format the date according to the locale.
+ *
+ * Requires php-intl to display international datetimes,
+ * otherwise default format '%c' will be returned.
+ *
+ * @param DateTimeInterface $date to format.
+ * @param bool $time Displays time if true.
+ * @param bool $intl Use international format if true.
+ *
+ * @return bool|string Formatted date, or false if the input is invalid.
+ */
+function format_date($date, $time = true, $intl = true)
+{
+ if (! $date instanceof DateTimeInterface) {