PHP中如何实现API负载均衡？

<?php
class LoadBalancer {
    private $servers;
    private $current = 0;

    public function __construct(array $servers) {
        $this->servers = $servers;
    }

    public function getServer() {
        $server = $this->servers[$this->current];
        $this->current = ($this->current + 1) % count($this->servers);
        return $server;
    }
}

$servers = [
    'server1.example.com',
    'server2.example.com',
    'server3.example.com'
];

$loadBalancer = new LoadBalancer($servers);

for ($i = 0; $i < 10; $i++) {
    echo $loadBalancer->getServer() . "\n";
}
?>

<?php
class LoadBalancer {
    private $servers;

    public function __construct(array $servers) {
        $this->servers = $servers;
    }

    public function getServer() {
        $leastConnections = PHP_INT_MAX;
        $selectedServer = null;

        foreach ($this->servers as $server) {
            $connections = $this->getServerConnections($server);
            if ($connections < $leastConnections) {
                $leastConnections = $connections;
                $selectedServer = $server;
            }
        }

        return $selectedServer;
    }

    private function getServerConnections($server) {
        // 这里假设我们有一个API可以获取服务器的连接数
        // 实际实现中可能需要根据具体情况调整
        $ch = curl_init("http://$server/api/connections");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $response = curl_exec($ch);
        curl_close($ch);

        return json_decode($response, true)['connections'];
    }
}

$servers = [
    'server1.example.com',
    'server2.example.com',
    'server3.example.com'
];

$loadBalancer = new LoadBalancer($servers);

for ($i = 0; $i < 10; $i++) {
    echo $loadBalancer->getServer() . "\n";
}
?>