Challenge 2 — Solution

Task: Write a function fetchJson($url) that uses cURL to GET a URL,
checks the HTTP status code, and returns the decoded JSON as an
associative array if the code is 200, or null otherwise. Call it with a
placeholder URL and handle both possible outcomes.

<?php
    function fetchJson(string $url): ?array {
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode === 200) {
            return json_decode($response, true);
        }

        return null;
    }

    $result = fetchJson("https://api.example.com/users/1");

    if ($result !== null) {
        echo "Fetched: " . $result['name'];
    } else {
        echo "Failed to fetch data from the API.";
    }
?>


Output:
(Depends entirely on whether the placeholder URL actually responds
with a real 200 status and valid JSON - for a genuinely unreachable
placeholder URL like the one above, the expected output is:)
Failed to fetch data from the API.

Notes:
- The return type ?array (a nullable array) matches exactly what the
  function can actually return - either a real decoded array on
  success, or null on any non-200 status - making the function's own
  contract explicit and self-documenting.
- Checking $httpCode === 200 specifically (rather than just checking
  whether curl_exec() returned something) is essential, since curl_exec()
  can return a normal-looking string body even for a 404 or 500 error
  page - the status code is the only reliable way to know if the
  request actually succeeded.
- The calling code checks "$result !== null" rather than a plain
  truthy/falsy check, since an empty (but successfully fetched)
  associative array would otherwise be indistinguishable from a genuine
  failure if a loose truthiness check were used instead.