how to paginate ElasticSearch results using PHP API - php

Question

following the example in the docs, I search in my type like that:
$params = [
'index' => $this->index,
'type' => $this->type,
"scroll" => "30s",
"size" => 10,
'body' => $json
];
$response = $this->es->search($params);
now $response includes 10 results and a _scroll_id. How can I use it to paginate my results? I am looking at this example
https://www.elastic.co/guide/en/elasticsearch/client/php-api/current/_search_operations.html#_scrolling
then the doc suggests to do:
while (isset($response['hits']['hits']) && count($response['hits']['hits']) > 0) {
$scroll_id = $response['_scroll_id'];
$response = $client->scroll([
"scroll_id" => $scroll_id, //...using our previously obtained _scroll_id
"scroll" => "30s" // and the same timeout window
]
);
}
but not clear if I have to do a new request or if the while loop is meant to store all the results in a variable and pass it to the template.
Any practical example to show?
thanks

Answer 1

After first request with scroll parameter, you will receive normal payload (_shards, took, hits, etc) and _scroll_id as well from elasticsearch. In hits you will have total number of found documents, hence you have: items per page and total count of items.
To figure out counts of pages - you need to do simple math.
To receive next batch of data from elasticsearch - run this:
curl 'localhost:9200/_search/scroll ' -d '{
"scroll" : "30s",
"scroll_id" : "cXVlcnlUaGVuRmV0Y2g7NTsxMzU0MDQzNjY6QnNHMjd0bXlTZ3Ftd1dkblRUd3NQZzsxMDE1NzI4Mjc6ajFzVmtLQUdSaEduRWFRVi1GZE05UTsxMDE1NzI4MjY6ajFzVmtLQUdSaEduRWFRVi1GZE05UTsxMDE1ODAzODc6TURuUG5nbzRUVU9NUUFjSERqM2hIQTsxMDE1ODAzODg6TURuUG5nbzRUVU9NUUFjSERqM2hIQTswOw=="
}'
With scroll you can only receive next batch, you can't jump on particular page.