proxy.php

<?php
  $envFile = __DIR__ . '/.env';

  function loadEnvFile($path) {
      if (!file_exists($path)) {
          return;
      }

      $lines = file($path, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
      foreach ($lines as $line) {
          if (strpos(trim($line), '#') === 0) {
              continue;
          }

          $parts = explode('=', $line, 2);
          if (count($parts) !== 2) {
              continue;
          }

          $name = trim($parts[0]);
          $value = trim($parts[1]);

          if ((substr($value, 0, 1) === '"' && substr($value, -1) === '"') ||
              (substr($value, 0, 1) === "'" && substr($value, -1) === "'")) {
              $value = substr($value, 1, -1);
          }

          putenv("$name=$value");
          $_ENV[$name] = $value;
          $_SERVER[$name] = $value;
      }
  }

  loadEnvFile($envFile);

  $appid = getenv('WEATHER_API_KEY') ?: '';
  if ($appid === '') {
      http_response_code(500);
      echo json_encode(['message' => 'WEATHER_API_KEY is not set']);
      exit;
  }

  header("Content-type: application/json\n\n");
  $params = $_SERVER['QUERY_STRING'];
  $host = "https://api.openweathermap.org/data/2.5/weather?$params&APPID=$appid";
  $ch = curl_init($host);
  curl_exec($ch);
  curl_close($ch);
?>