Get currentSite.handle in Element API

I need to get the currentSite in Element API. How can this be achieved? Is it as a slug in the endpoint URL? or as a Query param? Here is the current code:

<?php

use craftelementsEntry;
use crafthelpersUrlHelper;
use craftservicesSites;

return [
    'defaults' => [
        'resourceKey' => 'suggestions',
        'cache' => false,
        'paginate' => false,
        'pretty' => true,
    ],
    'endpoints' => [
        'api/search.json' => function() {

        $searchQuery = Craft::$app->request->getQueryParam('query');
        $site = Craft::$app->request->getQueryParam('site');

        $sectionHandles = [
            'pages',
            'news',
        ];

        // Search criterias
        $criteria = [
            'section' => $sectionHandles,
            'search' => $searchQuery,
            'site' => $site,
            'orderBy' => 'score',
            'limit' => 10,
        ];

            return [
                'elementType' => Entry::class,
                'criteria' => $criteria,
                'paginate' => false,

            'transformer' => function(craftelementsEntry $entry) {

                return [
                    'title' => $entry->title,
                    'url' => $entry->url,
                ];
            },

            ];
        },
    ]
];

'api/search.json' => function() {

    $siteHandle = Craft::$app->getSites()->currentSite->handle;

    ...

    $criteria = [
        'site' => $siteHandle,
        ...
    ];

    return [
        ...
    ];
},