This PHP code defines a shortcode function that retrieves the latest posts from a WordPress site's API and displays them in a specific format on a webpage. It uses a transient to store the latest posts for a certain time period to improve performance. The shortcode can be added to a WordPress page or post using the add_shortcode function.

latest-posts-shortcode.php

<?php
function latest_posts_shortcode() {
    // Set the transient key and expiration time
    $transient_key = 'latest_posts';
    $expiration = DAY_IN_SECONDS;

    // Define the site URL and number of posts per page
    $site_url = 'https://example.com';
    $posts_per_page = 3;

    // Get the latest posts from the transient or the API
    if (false === ($posts = get_transient($transient_key))) {
        // Retrieve the latest posts from the API
        $api_url = $site_url . '/wp-json/wp/v2/posts?per_page=' . $posts_per_page;
        $data = file_get_contents($api_url);
        $posts = json_decode($data);

        // Set the transient with the latest posts and expiration time
        set_transient($transient_key, $posts, $expiration);
    }

    // Initialize output variable
    $output = '';

    // Loop through the posts and append them to the output
    $output .= '<div class="latest-posts-wrapper">';
    $count = 0;
    foreach($posts as $post) {
        $title = $post->title->rendered;
        $link = $post->link;
        $featured_image = $post->featured_media;
        $date = date("F d, Y", strtotime($post->date));
        $excerpt = $post->excerpt->rendered;
        $excerpt = substr($excerpt, 0, 100) . '...';

        // Retrieve the URL for the featured image
        $image_data = file_get_contents($site_url . '/wp-json/wp/v2/media/' . $featured_image);
        $image = json_decode($image_data);
        $image_url = $image->media_details->sizes->medium->source_url;

        $output .= '<div class="latest-post">';
        $output .= '<a href="' . $link . '" target="_blank" rel="noopener">';
        $output .= '<img src="' . $image_url . '" alt="' . $title . '">';
        $output .= '</a>';
        $output .= '<div class="latest-post-details">';
        $output .= '<h2><a href="' . $link . '" target="_blank" rel="noopener">' . $title . '</a></h2>';
        $output .= '<p class="date">' . $date . '</p>';
        $output .= '<div class="excerpt">' . $excerpt . '</div>';
        $output .= '</div>';
        $output .= '</div>';

        $count++;
        if ($count % 3 == 0) {
            $output .= '</div><div class="posts-row">';
        }
    }
    $output .= '</div>';

    return $output;
}
add_shortcode( 'latest_posts', 'latest_posts_shortcode' );