WordPress Wehook Request When Post is Published

webhook.php

<?php

/**
 * Utility class for handling web-hook requests.
 * It provides a method to send POST requests to a specified URL with retries and error handling.
 */
class WP_Webhook_Request
{
  protected const RETRY_COUNT_LIMIT = 3;
  protected const RETRY_DELAY_SECONDS = 2;
  protected const RETRY_MAX_DELAY_SECONDS = 8;
  protected const REQUEST_TIMEOUT_SECONDS = 5;

  private const WEBHOOK_ENDPOINT_URL = 'https://example.com/webhook';
  private const WEBHOOK_SIGNATURE_SECRET = SECURE_AUTH_KEY;

  /**
   * Posts a web-hook request with the given post data.
   * It encodes the post data as JSON, sets the necessary headers, and retries the request if it fails.
   */
  public static function post($post)
  {
    $json = wp_json_encode([
      'event' => 'post_published',
      'data'  => [
        'post' => [
          'id' => $post->ID,
          'type' => $post->post_type,
          'status' => $post->post_status,
          'title' => get_the_title($post),
          'excerpt' => get_the_excerpt($post),
          'permalink' => get_permalink($post),
          'published_at' => get_post_time('c', true, $post),
          'images' => [
            'thumbnail' => get_the_post_thumbnail_url($post, 'thumbnail'),
            'medium' => get_the_post_thumbnail_url($post, 'medium'),
            'large' => get_the_post_thumbnail_url($post, 'large'),
            'full' => get_the_post_thumbnail_url($post, 'full'),
          ],
        ],
      ],
    ]);

    if (! $json) {
      error_log('Webhook Error: Failed to encode data');

      return false;
    }

    $idempotency_key = hash('sha256', $post->ID);

    return static::postWithRetries($json, $idempotency_key);
  }

  /**
   * Posts a web-hook request with retries.
   * It sends a POST request to the web-hook URL with the provided JSON data and idempotency key.
   * If the request fails, it retries up to a specified limit with exponential back-off.
   *
   * @param  string   $json             The JSON-encoded data to be sent in the request body.
   * @param  string   $idempotency_key  The idempotency key to be used in the request headers.
   * @param  integer  $attempt_count    The current attempt count for retries.
   * @return boolean  True if the request was successful, false otherwise.
   */
  protected static function postWithRetries($json, $idempotency_key, $attempt_count = 0)
  {
    $success = false;

    $response = wp_remote_post(static::WEBHOOK_ENDPOINT_URL, [
      'body' => $json,
      'data_format' => 'body',
      'timeout' => static::REQUEST_TIMEOUT_SECONDS,
      'headers' => [
        'Content-Type' => 'application/json',
        'X-Webhook-Event' => 'post_published',
        'X-Webhook-Timestamp' => gmdate('c'),
        'X-Idempotency-Key' => $idempotency_key,
        'X-Signature' => hash_hmac('sha256', $json, static::WEBHOOK_SIGNATURE_SECRET),
      ],
    ]);

    if (! is_wp_error($response)) {
      $code = (int) wp_remote_retrieve_response_code($response);
      $success = (bool) $code >= 200 && $code < 300;
    }

    // If the request was successful, we're done
    if ($success) return true;

    // If we haven't reached the maximum number of retries, retry the request
    if ($attempt_count < static::RETRY_COUNT_LIMIT) {
      $attempt_count += 1;

      // Sleep with exponential back off and a maximum delay of 8 seconds
      sleep(
        min(pow(static::RETRY_DELAY_SECONDS, $attempt_count), static::RETRY_MAX_DELAY_SECONDS)
      );

      return static::postWithRetries($json, $idempotency_key, $attempt_count);
    }

    // If we reach here, all attempts failed
    if (is_wp_error($response)) {
      error_log('Webhook Error (after ' . static::RETRY_COUNT_LIMIT . ' retries): ' . $response->get_error_message());
    } else {
      $code = is_array($response) ? wp_remote_retrieve_response_code($response) : 'N/A';
      $body = is_array($response) ? wp_remote_retrieve_body($response) : '';
      error_log('Webhook Error (after ' . static::RETRY_COUNT_LIMIT . " retries):\r\nHTTP Status Code: $code\r\nResponse Body: $body");
    }

    return false;
  }
}

/**
 * Custom post type for Anuncios (Notices).
 */
class WP_Anuncios
{
  public const SLUG = 'anuncios';
  public const INFO_MESSAGE = "Cuando publiques un Anuncio, todos los usuarios recibirán un correo electrónico notificándoles sobre el nuevo anuncio.";

  /**
   * Initialize the Anuncios post type and its related functionality.
   */
  public static function init()
  {
    add_theme_support('post-thumbnails');

    WP_Anuncios::actionRegisterPostType();
    WP_Anuncios::actionDisableComments();
    WP_Anuncios::actionAdminInfoMessage();
    WP_Anuncios::actionBlockEditorInfoMessage();
    WP_Anuncios::actionPublishAnuncios();
    WP_Anuncios::actionLoadTranslations();
  }

  /**
   * Check if the current screen is the Anuncios post type.
   */
  public static function isActiveScreen()
  {
    /** @var WP_Screen|null $screen */
    $screen = get_current_screen();

    return isset($screen->post_type) && $screen->post_type === WP_Anuncios::SLUG;
  }

  /**
   * Check if the given post is of the Anuncios post type.
   */
  public static function isPostType($post)
  {
    return isset($post->post_type) && $post->post_type === WP_Anuncios::SLUG;
  }

  /*
  |--------------------------------------------------------------------------
  | WordPress Register Post Type & Disable Comments
  |--------------------------------------------------------------------------
  */

  /**
   * Create custom post type for notices.
   */
  public static function actionRegisterPostType()
  {
    /**
     * Create custom post type for notices.
     */
    add_action('init', function () {
      register_post_type(WP_Anuncios::SLUG, [
        'public'             => true,
        'show_in_menu'       => true,
        'has_archive'        => true,
        'show_in_rest'       => true,
        'publicly_queryable' => true,
        'capability_type'    => 'post',
        'menu_icon'          => 'dashicons-megaphone',
        'rewrite'            => ['slug' => WP_Anuncios::SLUG],
        'supports'           => ['title', 'editor', 'thumbnail', 'excerpt', 'custom-fields'],
        'labels'             => [
          'name'                  => _x('Anuncios', 'Post type general name', 'zafiro-child'),
          'singular_name'         => _x('Anuncio', 'Post type singular name', 'zafiro-child'),
          'menu_name'             => _x('Anuncios', 'Admin Menu text', 'zafiro-child'),
          'name_admin_bar'        => _x('Anuncio', 'Add New on Toolbar', 'zafiro-child'),
          'add_new'               => __('Agregar nuevo', 'zafiro-child'),
          'add_new_item'          => __('Agregar nuevo anuncio', 'zafiro-child'),
          'new_item'              => __('Nuevo anuncio', 'zafiro-child'),
          'edit_item'             => __('Editar anuncio', 'zafiro-child'),
          'view_item'             => __('Ver anuncio', 'zafiro-child'),
          'all_items'             => __('Todos los anuncios', 'zafiro-child'),
          'search_items'          => __('Buscar anuncios', 'zafiro-child'),
          'not_found'             => __('No se encontraron anuncios.', 'zafiro-child'),
          'not_found_in_trash'    => __('No hay anuncios en la papelera.', 'zafiro-child'),
          'featured_image'        => __('Imagen destacada', 'zafiro-child'),
          'set_featured_image'    => __('Establecer imagen destacada', 'zafiro-child'),
          'remove_featured_image' => __('Eliminar imagen destacada', 'zafiro-child'),
          'use_featured_image'    => __('Usar como imagen destacada', 'zafiro-child'),
          'archives'              => __('Archivo de anuncios', 'zafiro-child'),
          'insert_into_item'      => __('Insertar en el anuncio', 'zafiro-child'),
          'uploaded_to_this_item' => __('Subido a este anuncio', 'zafiro-child'),
          'filter_items_list'     => __('Filtrar lista de anuncios', 'zafiro-child'),
          'items_list_navigation' => __('Navegación de la lista de anuncios', 'zafiro-child'),
          'items_list'            => __('Lista de anuncios', 'zafiro-child'),
        ],
      ]);
    });
  }

  /**
   * Disable comments for the Anuncios post type.
   * This function modifies the comments behavior, hides the comments meta-box in the admin area,
   * and removes the comments column from the admin index for the Anuncios post type.
   */
  public static function actionDisableComments()
  {
    // Explicitly close comments for the post type
    add_filter('comments_open', function ($open, $post_id) {
      /** @var WP_Post|null $post */
      $post = get_post($post_id);

      return WP_Anuncios::isPostType($post) ? false : $open;
    }, 10, 2);

    add_filter('pings_open', function ($open, $post_id) {
      /** @var WP_Post|null $post */
      $post = get_post($post_id);

      return WP_Anuncios::isPostType($post) ? false : $open;
    }, 10, 2);

    // Hide comments meta-box for the post type
    add_action('admin_menu', function () {
      remove_meta_box('commentsdiv', WP_Anuncios::SLUG, 'normal');
      remove_meta_box('commentstatusdiv', WP_Anuncios::SLUG, 'normal');
    });

    // Hide comments column in admin index for the post type
    add_filter('manage_' . WP_Anuncios::SLUG . '_posts_columns', function ($columns) {
      if (isset($columns['comments'])) {
        unset($columns['comments']);
      }

      return $columns;
    });
  }

  /*
  |--------------------------------------------------------------------------
  | WordPress Display Info Message to Admins
  |--------------------------------------------------------------------------
  */

  /**
   * Add custom info notice on classic admin pages.
   */
  public static function actionAdminInfoMessage()
  {
    add_action('admin_notices', function () {
      if (! WP_Anuncios::isActiveScreen()) return;

      $message = esc_html(WP_Anuncios::INFO_MESSAGE);

      echo <<<HTML
        <div class="notice notice-info"><p><strong>Importante:</strong> $message</p></div>
      HTML;
    });
  }

  /**
   * Add custom info notice on block editor admin pages.
   */
  public static function actionBlockEditorInfoMessage()
  {
    add_action('enqueue_block_editor_assets', function () {
      wp_enqueue_script('wp-notices');

      if (! WP_Anuncios::isActiveScreen()) return;

      $message = esc_js(strip_tags(WP_Anuncios::INFO_MESSAGE));

      wp_add_inline_script('wp-notices', <<<JS
        window.wp && wp.domReady && wp.domReady(function() {
          wp.data
            .dispatch('core/notices')
            .createNotice('info', 'Importante: $message', { isDismissible: false });
        });
      JS);
    });
  }

  /*
  |--------------------------------------------------------------------------
  | WordPress Bootstrap Web-Hook to Send Emails on Post Publish
  |--------------------------------------------------------------------------
  */

  /**
   * Call email web-hook when a new post is published.
   */
  public static function actionPublishAnuncios()
  {
    add_action('publish_' . WP_Anuncios::SLUG, function ($post_id) {
      /** @var WP_Post|null $post */
      $post = get_post($post_id);

      if (! isset($post->post_status) || $post->post_status !== 'publish') return;

      WP_Webhook_Request::post($post);
    });
  }

  /*
  |--------------------------------------------------------------------------
  | WordPress Add Translations for the Anuncios Post Type
  |--------------------------------------------------------------------------
  */

  /**
   * Load translations for the Anuncios post type.
   */
  public static function actionLoadTranslations()
  {
    add_action('after_setup_theme', function () {
      load_theme_textdomain('zafiro-child', get_stylesheet_directory() . '/languages');
    });
  }
}

WP_Anuncios::init();

This implements a custom post-type
The webhook request has a naive implementation of retries with exponential backoff
The headers include a signature for validation and idempotency key enable handling duplicated requests