0Request and response handling lets your WordPress site talk to users and other systems. It helps you get data from visitors and send back the right information.
<?php // Access request data $variable = $_GET['param'] ?? $_POST['param'] ?? null; // Send response wp_send_json_success($data); wp_send_json_error($error_message); // Register REST API endpoint add_action('rest_api_init', function () { register_rest_route('namespace/v1', '/route', [ 'methods' => 'GET', 'callback' => 'your_callback_function', ]); });
Use $_GET and $_POST to get data sent by users.
Use wp_send_json_success() and wp_send_json_error() to send JSON responses easily.
<?php // Get a value from URL query $name = $_GET['name'] ?? 'Guest'; echo 'Hello, ' . esc_html($name);
<?php // Send JSON success response $data = ['message' => 'Success!']; wp_send_json_success($data);
<?php // Register a REST API endpoint add_action('rest_api_init', function () { register_rest_route('myplugin/v1', '/hello', [ 'methods' => 'GET', 'callback' => function () { return ['greeting' => 'Hello from REST API']; }, ]); });
This plugin adds a simple form using a shortcode. When the form is submitted, it reads the name and shows a greeting.
<?php /* Plugin Name: Simple Request Response Demo */ // Handle form submission add_action('init', function () { if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['user_name'])) { $name = sanitize_text_field($_POST['user_name']); // Store name in session or do something echo 'Hello, ' . esc_html($name) . '!'; exit; } }); // Add a shortcode to show a form add_shortcode('name_form', function () { return '<form method="POST"> <label for="user_name">Enter your name:</label> <input type="text" id="user_name" name="user_name" required> <button type="submit">Submit</button> </form>'; });
Always sanitize and validate user input to keep your site safe.
Use WordPress functions like esc_html() to safely show data.
For AJAX or REST API, use proper hooks and return data in JSON format.
Request handling means getting data users send to your site.
Response handling means sending back messages or data to users.
WordPress offers simple ways to handle both with PHP and REST API.
$_POST superglobal in PHP.$_GET holds URL query parameters, $_REQUEST combines GET, POST, and COOKIE but is less specific, and $GLOBALS holds all global variables.$_POST -> Option B$_POST [OK]WP_REST_Response, array, or WP_Error. The framework handles headers, JSON encoding, and status.wp_send_json($data); sends JSON and exits with wp_die(), suitable for AJAX but bypasses REST processing/filters. echo json_encode($data); outputs JSON without headers or exit. header('Content-Type: text/plain'); echo $data; wrong type.function get_custom_data(\WP_REST_Request $request) {
$param = $request->get_param('id');
if ($param === '42') {
return ['message' => 'Found'];
}
return new WP_Error('not_found', 'ID not found', ['status' => 404]);
}
What will be the HTTP status code if the request URL includes ?id=42?id equals '42'. If yes, it returns an array with message 'Found'.function my_callback(\WP_REST_Request $request) {
$data = $request->get_param('data');
wp_send_json_success($data);
echo 'Done';
}
What is the problem with this code?echo 'Done'; line is unreachable because the script exits before it.$request->get_json_params() safely parses JSON body data.WP_REST_Response with data and status code is the recommended way to send structured responses.get_body_params() which checks form data ($_POST), empty for JSON body POSTs. C uses $_POST['name'] directly, same issue. D manually reads input bypassing framework helpers and uses wp_send_json() which exits.Pass the test and this pattern moves unknown strong while earning +1 Grip toward your certificate.