Tạo đường dẫn search bằng add_query_arg (ok)

https://developer.wordpress.org/reference/functions/add_query_arg/

<?php
function _http_build_query($data, $prefix = null, $sep = null, $key = '', $urlencode = true) {
  $ret = array();
  foreach ((array) $data as $k => $v) {
    if ($urlencode) {
      $k = urlencode($k);
    }
    if (is_int($k) && null != $prefix) {
      $k = $prefix . $k;
    }
    if (!empty($key)) {
      $k = $key . '%5B' . $k . '%5D';
    }
    if (null === $v) {
      continue;
    } elseif (false === $v) {
      $v = '0';
    }
    if (is_array($v) || is_object($v)) {
      array_push($ret, _http_build_query($v, '', $sep, $k, $urlencode));
    } elseif ($urlencode) {
      array_push($ret, $k . '=' . urlencode($v));
    } else {
      array_push($ret, $k . '=' . $v);
    }
  }
  if (null === $sep) {
    $sep = ini_get('arg_separator.output');
  }
  return implode($sep, $ret);
}
function build_query($data) {
  return _http_build_query($data, null, '&', '', false);
}
function map_deep($value, $callback) {
  if (is_array($value)) {
    foreach ($value as $index => $item) {
      $value[$index] = map_deep($item, $callback);
    }
  } elseif (is_object($value)) {
    $object_vars = get_object_vars($value);
    foreach ($object_vars as $property_name => $property_value) {
      $value->$property_name = map_deep($property_value, $callback);
    }
  } else {
    $value = call_user_func($callback, $value);
  }
  return $value;
}
function urlencode_deep($value) {
  return map_deep($value, 'urlencode');
}
function wp_parse_str($string, &$array) {
  parse_str($string, $array);
}
function add_query_arg(...$args) {
  if (is_array($args[0])) {
    if (count($args) < 2 || false === $args[1]) {
      $uri = $_SERVER['REQUEST_URI'];
    } else {
      $uri = $args[1];
    }
  } else {
    if (count($args) < 3 || false === $args[2]) {
      $uri = $_SERVER['REQUEST_URI'];
    } else {
      $uri = $args[2];
    }
  }
  $frag = strstr($uri, '#');
  if ($frag) {
    $uri = substr($uri, 0, -strlen($frag));
  } else {
    $frag = '';
  }
  if (0 === stripos($uri, 'http://')) {
    $protocol = 'http://';
    $uri      = substr($uri, 7);
  } elseif (0 === stripos($uri, 'https://')) {
    $protocol = 'https://';
    $uri      = substr($uri, 8);
  } else {
    $protocol = '';
  }
  if (strpos($uri, '?') !== false) {
    list($base, $query) = explode('?', $uri, 2);
    $base .= '?';
  } elseif ($protocol || strpos($uri, '=') === false) {
    $base  = $uri . '?';
    $query = '';
  } else {
    $base  = '';
    $query = $uri;
  }
  wp_parse_str($query, $qs);
  $qs = urlencode_deep($qs); // This re-URL-encodes things that were already in the query string.
  if (is_array($args[0])) {
    foreach ($args[0] as $k => $v) {
      $qs[$k] = $v;
    }
  } else {
    $qs[$args[0]] = $args[1];
  }
  foreach ($qs as $k => $v) {
    if (false === $v) {
      unset($qs[$k]);
    }
  }
  $ret = build_query($qs);
  $ret = trim($ret, '?');
  $ret = preg_replace('#=(&|$)#', '$1', $ret);
  $ret = $protocol . $base . $ret . $frag;
  $ret = rtrim($ret, '?');
  return $ret;
}
$url      = "https://photon.komoot.io/reverse";
$full_url = add_query_arg(array(
  'lon' => 123,
  'lat' => 456,
), $url);
echo '<pre>';
var_export($full_url);
echo '</pre>';