The client also supports an extended host configuration syntax. The inline configuration method relies on PHP’s filter_var() and parse_url() methods to validate and extract the components of a URL. Unfortunately, these built-in methods run into problems with certain edge-cases. For example, filter_var() will not accept URL’s that have underscores (which are questionably legal, depending on how you interpret the RFCs). Similarly, parse_url() will choke if a Basic Auth’s password contains special characters such as a pound sign (#) or question-marks (?).

For this reason, the client supports an extended host syntax which provides greater control over host initialization. None of the components are validated, so edge-cases like underscores in domain names will not cause problems.

The extended syntax is an array of parameters for each host:

$hosts = [
    // This is effectively equal to: "https://username:password!#$?*abc@foo.com:9200/"
    [
        'host' => 'foo.com',
        'port' => '9200',
        'scheme' => 'https',
        'user' => 'username',
        'pass' => 'password!#$?*abc'
    ],

    // This is equal to "http://localhost:9200/"
    [
        'host' => 'localhost',    // Only host is required
    ]
];
$client = ClientBuilder::create()           // Instantiate a new ClientBuilder
                    ->setHosts($hosts)      // Set the hosts
                    ->build();              // Build the client object

Only the host parameter is required for each configured host. If not provided, the default port is 9200. The default scheme is http.