PHP 根据 ip 获取 当前城市

/**
 * 根据 ip 获取 当前城市
 */
function get_city_by_ip()
{
    if (! empty($_SERVER["HTTP_CLIENT_IP"])) {
        $cip = $_SERVER["HTTP_CLIENT_IP"];
    } elseif (! empty($_SERVER["HTTP_X_FORWARDED_FOR"])) {
        $cip = $_SERVER["HTTP_X_FORWARDED_FOR"];
    } elseif (! empty($_SERVER["REMOTE_ADDR"])) {
        $cip = $_SERVER["REMOTE_ADDR"];
    } else {
        $cip = "";
    }
    $url = 'https://restapi.amap.com/v3/ip';
    $data = array(
        'output' => 'json',
        'key' => '16199cf2aca1fb54d0db495a3140b8cb',
        'ip' => $cip
    );
    
    $postdata = http_build_query($data);
    $opts = array(
        'http' => array(
            'method' => 'POST',
            'header' => 'Content-type: application/x-www-form-urlencoded',
            'content' => $postdata
        )
    );
    
    $context = stream_context_create($opts);
    
    $result = file_get_contents($url, false, $context);
    if (! empty($result)) {
        $res = json_decode($result, true);
        
        if (! empty($res)) {
            if (empty($res['province'])) {
                $res['province'] = '北京市';
            }
            if (! empty($res['province']) && $res['province'] == "局域网") {
                $res['province'] = '北京市';
            }
            if(count($res['province']) == 0){
                $res['province'] = '北京市';
            }
            if (count($res['city']) == 0) {
                $res['city'] = '北京市';
            }
        } else {
            $res['province'] = '北京市';
            $res['city'] = '北京市';
        }
        
        return $res;
    } else {
        return array(
            "province" => '北京市',
            "city" => '北京市'
        );
    }
}