Google-Place-Reviews.php

<?php 

class Place_Reviews {
    // URL to the Google Place API
    protected $apiUrl = 'https://maps.googleapis.com/maps/api/place/details/json';
     
    // Google Place ID
    protected $place_id;
     
    public function __construct($place_id)
    {
        $this->place_id = $place_id;

        add_shortcode('get-review', array($this, 'shortcode'));
    }
     
    public function getPlaceRating()
    {
        $place_id = $this->place_id;

        $url = add_query_arg( array(
            'place_id' => $place_id,
            'fields' => 'rating',
            'key' => '' # API KEY HERE
        ), 'https://maps.googleapis.com/maps/api/place/details/json' );
         
        $json = wp_remote_get($url);
         
        $details = json_decode($json['body']);
         
        if ( isset( $details['result']['rating'] ) ) {
            return $details['result']['rating'];
            #update_post_meta( $post_id, '_star_rating', $meta_field, true );
        }
         
    }

    public function shortcode()
    {
           // Contents of this function will execute when the blogger
          // uses the [shortcode_name] shortcode.
    }
}

$place_id = ''; # PLACE ID
$PlaceReviews = new Place_Reviews($place_id);
$meta = $PlaceReviews->getPlaceRating();
echo $meta;