How is Elasticsearch used in PHP?

In PHP, it is typically necessary to use the official PHP client library provided by Elasticsearch when working with Elasticsearch. These libraries give PHP developers an interface to communicate with Elasticsearch clusters and perform various operations such as indexing documents and searching documents.

Here is a simple example demonstrating how to communicate with an Elasticsearch cluster in PHP using the Elasticsearch client library.

1. Install the Elasticsearch client library.

composer require elasticsearch/elasticsearch

1. Connect to the Elasticsearch cluster.

require 'vendor/autoload.php';

use Elasticsearch\ClientBuilder;

$hosts = [
    'http://localhost:9200'
];

$client = ClientBuilder::create()->setHosts($hosts)->build();

1. Index document:

$params = [
    'index' => 'my_index',
    'type' => 'my_type',
    'id' => '1',
    'body' => [
        'title' => 'Test Document',
        'content' => 'This is a test document'
    ]
];

$response = $client->index($params);

1. Search documents:

$params = [
    'index' => 'my_index',
    'type' => 'my_type',
    'body' => [
        'query' => [
            'match' => [
                'title' => 'test'
            ]
        ]
    ]
];

$response = $client->search($params);

This is just a simple example, you can perform other operations based on your needs and the configuration of your Elasticsearch cluster. For more information on using Elasticsearch in PHP, please refer to the official Elasticsearch documentation and the documentation of the PHP client library.