Efficient WordPress Latest Post content fetch for a user

wordpress-latest-post-content-fetch.php

/**
 * Fetch of Latest Post content of a user by post type.
 *
 * @param array  $atts shortcode atts.
 * @param string $content n/a
 *
 * @return mixed|string
 */
function buddydev_user_last_post_shortcode( $atts, $content = '' ) {
	$atts = shortcode_atts( array(
		// by default, If BuddyPress is active, use displayed user.
		'user_id'   => function_exists( 'bp_displayed_user_id' ) ? bp_displayed_user_id() : 0,
		'post_type' => 'post',
	), $atts );

	$user_id = $atts['user_id'];
	if ( ! $user_id ) {
		return $content;
	}

	global $wpdb;

	$last_post_id = get_transient( "bp-user-last-post-{$atts['post_type']}-{$user_id}" );

	if ( ! $last_post_id ) {
		$last_post_id = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM {$wpdb->posts} WHERE post_type = %s AND post_status =%s AND post_author = %d ORDER BY post_modified_gmt DESC LIMIT 0, 1" , $atts['post_type'], 'publish', $atts['user_id'] ) );

		if ( ! empty( $last_post_id ) ) {
			set_transient( "bp-user-last-post-{$atts['post_type']}-{$user_id}", $last_post_id, DAY_IN_SECONDS );
		}
	}

	if ( ! $last_post_id ) {
		return '';
	}

	$post = get_post( $last_post_id );
	if ( ! $post ) {
		return $content;
	}

	return apply_filters( 'the_content', $post->post_content );
}

add_shortcode( 'bp-user-last-post', 'buddydev_user_last_post_shortcode' );

/**
 * Clear transient on New Post, trash post, delete post.
 *
 * @param int $post_id post id.
 */
function buddydev_clear_last_post_transient( $post_id ) {
	if ( ! defined( 'DOING_AUTOSAVE' ) ) {
		$post = get_post( $post_id );
		delete_transient( "bp-user-last-post-{$post->post_type}-{$post->post_author}" );
	}
}

// on new post or delete post clear transient.
add_action( 'save_post', 'buddydev_clear_last_post_transient' );
add_action( 'wp_trash_post', 'buddydev_clear_last_post_transient' );
add_action( 'before_delete_post', 'buddydev_clear_last_post_transient' );

function buddydev_delete_user_post_association( $post_id, $data ) {
    $post = get_post( $post_id );
    if( $post->post_author == $data['post_author'] ) {
        return ;
    }
	delete_transient( "bp-user-last-post-{$post->post_type}-{$post->post_author}" );

}
add_action( 'pre_post_update', 'buddydev_delete_user_post_association', 10, 2 );