How to apply pagination for custom endpoint request in wordpress? - json

Question

I have created a custom restful API endpoint in WordPress which returns the JSON with the only required fields.
So with this one when I go to the example.com/wp-json/wl/posts, it returns 5 posts as I have limited the number of the posts.
function wl_posts() {
$args = [
'numberposts' => 99999,
'post_type' => 'post'
];
$posts = get_posts($args);
$data = [];
$i = 0;
foreach($posts as $post) {
$data[$i]['id'] = $post->ID;
$data[$i]['title'] = $post->post_title;
$data[$i]['content'] = $post->post_content;
$data[$i]['slug'] = $post->post_name;
$data[$i]['featured_image']['thumbnail'] = get_the_post_thumbnail_url($post->ID, 'thumbnail');
$i++;
}
return $data;
}
add_action('rest_api_init', function() {
register_rest_route('wl/v1', 'posts', [
'methods' => 'GET',
'callback' => 'wl_posts',
]);
});
But I also want to add the pagination, so if I add ?page=2 , it should return another 5 posts.
How can that be archived?

Answer 1

When visiting /?rest_route=/ or /wp-json/wp/v2/pages you can drill down into ie. wp/v2/pages/endpoints/0/args then check with page and per_page
curl http://YOUR-SITE/wp-json/wl/v1/posts/?per_page=1&page=2
Publish arguments for reference
We can define and publish these as arguments. This is not required but they are now in line with posts and pages
add_action('rest_api_init', function() {
register_rest_route('wl/v1', 'posts', [
'methods' => 'GET',
'callback' => 'wl_posts',
'args' => [
'page' => [
'description' => 'Current page',
'type' => "integer",
],
'per_page' => [
'description' => 'Items per page',
'type' => "integer",
]
],
]);
});
Fetch arguments
As get_posts has its own logic and it uses WP_Query in the end let's use WP_Query for the better.
function wl_posts() {
$args = [];
if (isset($_REQUEST['per_page'])) {
$args['posts_per_page'] = (int) $_REQUEST['per_page'];
}
if (isset($_REQUEST['page'])) {
$args['page'] = (int) $_REQUEST['page'];
}
$args['post_type'] = 'post';
$get_posts = new WP_Query;
$posts= $get_posts->query( $args );
$data = [];
$i = 0;
foreach($posts as $post) {
$data[$i]['id'] = $post->ID;
$data[$i]['title'] = $post->post_title;
$data[$i]['content'] = $post->post_content;
$data[$i]['slug'] = $post->post_name;
$data[$i]['featured_image']['thumbnail'] =
get_the_post_thumbnail_url($post->ID, 'thumbnail');
$i++;
}
return $data;
}