On WordPress login, redirect to the last post you were viewing or custom page if no last page available

redirect-login-last-post-custom.php

<?php

/**
 * On login, redirect to the last post viewed or custom page if no last page available.
 * Add this code into a custom plugin.
 * Note that many themes and plugins hook into login_redirect.
 * Whichever hook has the highest priority will be the last call
 * on where to redirect. The priority below is set to 20.
 * Note also that some URLs/pages may note be "posts"
 * and may not have an ID we can track.
 * Note also that some pages are excluded. You may want to exclude other pages.
 * Note also that this may override any specific redirect_to passed in
 * by URL parameter.
 */

/**
 * Remember last post ID
 */
function my_remember_last_post_id() {
	global $pmpro_pages;

	$queried_object = get_queried_object();

	// don't need to track if already logged in
	if ( is_user_logged_in() ) {
		return;
	}

	// no post?
	if ( empty( $queried_object ) || empty( $queried_object->ID ) ) {
		return;
	}

	// don't track the login page
	if ( function_exists( 'pmpro_is_login_page' ) && pmpro_is_login_page() ) {
		return;
	}

	// don't track pmpro pages
	if ( is_array( $pmpro_pages ) && in_array( $queried_object->ID, $pmpro_pages ) ) {
		return;
	}

	// Okay set it
	setcookie( 'last_post_viewed', $queried_object->ID, null, '/' );
}
add_action( 'wp', 'my_remember_last_post_id' );

/**
 * On login, redirect to the last post viewed.
 */
function my_redirect_to_last_post_id( $redirect_to, $request, $user ) {
	// If no redirect already, use the last page viewed
	if ( ! empty( $_COOKIE['last_post_viewed'] ) ) {
		$redirect_to = get_permalink( intval( $_COOKIE['last_post_viewed'] ) );
	} else {
		$redirect_to = home_url( 'community' );
	}
	return $redirect_to;
}
add_filter( 'login_redirect', 'my_redirect_to_last_post_id', 20, 3 );