Fix Load Balancer Error in PHP

PHP Behind a Load Balancer

PHP relies heavily on $_SERVER variables for request information. Behind a load balancer, these variables reflect the proxy connection, not the client — leading to broken HTTPS detection, wrong client IPs, and session issues.

HTTPS Detection

PHP checks $_SERVER['HTTPS'], but the load balancer terminates SSL:

// In your bootstrap or .htaccess
if ($_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
    $_SERVER['HTTPS'] = 'on';
}

Or in Apache .htaccess:

SetEnvIf X-Forwarded-Proto "https" HTTPS=on

Real Client IP

function getClientIp(): string {
    $headers = ['HTTP_X_FORWARDED_FOR', 'HTTP_X_REAL_IP', 'REMOTE_ADDR'];
    foreach ($headers as $header) {
        if (!empty($_SERVER[$header])) {
            // X-Forwarded-For can contain multiple IPs
            $ips = explode(',', $_SERVER[$header]);
            return trim($ips[0]);
        }
    }
    return $_SERVER['REMOTE_ADDR'];
}

Session Handling

File sessions break with multiple servers. Switch to Redis:

; php.ini
session.save_handler = redis
session.save_path = "tcp://redis-service:6379"

Health Check

// healthz.php
http_response_code(200);
echo 'ok';
exit;

Keep it simple — don't include your framework bootstrap, which might fail and return a 500 to the load balancer.

Bugsly's PHP SDK hooks into error handlers and exception handlers to capture errors with request context, including the real client IP parsed from proxy headers.