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LaravelPHP

Laravel Integration

Integrate ImmutableLog into any Laravel application with a terminable middleware. The `terminate()` method runs after the response is sent to the client — so sending is naturally fire-and-forget, adding no latency.

Installation

The middleware uses Guzzle (already present in most Laravel projects) and ramsey/uuid (bundled with the framework).

bash
# Guzzle já vem no Laravel; instale se necessário:
composer require guzzlehttp/guzzle

Middleware code

Save it in `app/Http/Middleware/ImmutableLogMiddleware.php`. `handle()` records the timestamp and request_id; `terminate()` builds the event and sends it after the response. Query params go through `redact()`.

php
<?php
// app/Http/Middleware/ImmutableLogMiddleware.php
namespace App\Http\Middleware;

use Closure;
use GuzzleHttp\Client;
use Illuminate\Http\Request;
use Ramsey\Uuid\Uuid;

class ImmutableLogMiddleware
{
    // Chaves cujos valores sao mascarados antes do envio (PII/segredos).
    private const SENSITIVE = [
        'password', 'pwd', 'senha', 'token', 'access_token', 'refresh_token', 'api_key',
        'apikey', 'secret', 'client_secret', 'authorization', 'auth', 'credit_card',
        'card_number', 'cvv', 'cpf', 'otp', 'code',
    ];

    public function handle(Request $request, Closure $next)
    {
        $request->attributes->set(
            'imtbl.request_id',
            $request->header('X-Request-Id') ?? Uuid::uuid4()->toString()
        );
        $request->attributes->set('imtbl.started_at', microtime(true));

        return $next($request);
    }

    // terminate() roda DEPOIS da resposta ser enviada — fire-and-forget natural.
    public function terminate(Request $request, $response): void
    {
        try {
            $apiKey = env('IMTBL_API_KEY');
            if (empty($apiKey)) {
                return;
            }
            if (in_array($request->getPathInfo(), ['/health', '/healthz', '/metrics'], true)) {
                return;
            }

            $startedAt = $request->attributes->get('imtbl.started_at', microtime(true));
            $latencyMs = (int) ((microtime(true) - $startedAt) * 1000);
            $status    = $response->getStatusCode();
            $requestId = $request->attributes->get('imtbl.request_id');

            $kind = $status >= 400 ? 'error'
                : ($status >= 300 ? 'info' : ($status >= 200 ? 'success' : 'info'));
            $eventName = $request->attributes->get('imtbl.event_name')
                ?? 'http.' . $request->method() . '.' . $request->path();

            $context = ['ip' => $request->ip(), 'user_agent' => $request->userAgent() ?? 'unknown'];
            if ($user = $request->user()) {
                $context['user_id'] = $user->getAuthIdentifier();
                $context['email']   = $user->email ?? null;
            }

            $payload = [
                'id'        => Uuid::uuid4()->toString(),
                'kind'      => $kind,
                'message'   => $request->method() . ' /' . $request->path() . ' -> ' . $status,
                'timestamp' => gmdate('c'),
                'context'   => $context,
                'request'   => [
                    'request_id'   => $requestId,
                    'method'       => $request->method(),
                    'path'         => '/' . $request->path(),
                    // query params passam por redact() — nunca enviar segredos em claro.
                    'query_params' => self::redact($request->query()) ?: null,
                ],
                'metrics'   => ['latency_ms' => $latencyMs, 'status_code' => $status],
                'severity'  => $kind === 'error' ? 'high' : 'low',
            ];
            if ($kind === 'error') {
                $payload['error'] = [
                    'status_code' => $status,
                    'retryable'   => in_array($status, [408, 429, 500, 502, 503, 504], true),
                ];
            }

            // Trilha: attribute imtbl.trail -> header X-Imtbl-Trail.
            $trail = self::sanitizeTrail(
                $request->attributes->get('imtbl.trail') ?? $request->header('X-Imtbl-Trail')
            );

            // Todos os valores de meta precisam ser strings.
            $meta = [
                'type'       => $kind,
                'event_name' => $eventName,
                'service'    => env('IMTBL_SERVICE_NAME', 'laravel-service'),
                'request_id' => $requestId,
                'env'        => app()->environment(),
            ];
            if ($trail !== null) {
                $meta['immutable_trail'] = $trail;
            }

            $headers = [
                'Authorization' => "Bearer {$apiKey}",
                'Content-Type'  => 'application/json',
                // Idempotency-Key e OBRIGATORIO (sem ele a API responde 400).
                'Idempotency-Key'         => "{$eventName}-{$requestId}",
                'Request-Id'              => $requestId,
                'X-Client-TZ'             => 'America/Sao_Paulo',
                'X-Client-Offset-Minutes' => '-180',
            ];
            if ($trail !== null) {
                $headers['X-Imtbl-Trail'] = $trail;
            }

            (new Client(['timeout' => 5]))->post(
                (env('IMTBL_URL') ?: 'https://api.immutablelog.com') . '/v1/events',
                ['headers' => $headers, 'json' => ['payload' => json_encode($payload), 'meta' => $meta]]
            );
        } catch (\Throwable $e) {
            // Never let audit logging break the application.
        }
    }

    private static function redact(array $data): array
    {
        foreach ($data as $k => $v) {
            if (is_string($k) && in_array(strtolower($k), self::SENSITIVE, true)) {
                $data[$k] = '***REDACTED***';
            } elseif (is_array($v)) {
                $data[$k] = self::redact($v);
            }
        }
        return $data;
    }

    // Normaliza o immutable_trail (trim, nao-vazio, max 256, sem ':').
    private static function sanitizeTrail(?string $value): ?string
    {
        if ($value === null) {
            return null;
        }
        $v = trim($value);
        if ($v === '') {
            return null;
        }
        $v = str_replace(':', '-', $v);
        if (mb_strlen($v) > 256) {
            $v = mb_substr($v, 0, 256);
        }
        return $v;
    }
}

Middleware registration

On Laravel 11+, register it in `bootstrap/app.php`. On earlier versions, add it to the `$middleware` property of `app/Http/Kernel.php`.

php
<?php
// Laravel 11+ — bootstrap/app.php
use App\Http\Middleware\ImmutableLogMiddleware;

return Application::configure(basePath: dirname(__DIR__))
    ->withMiddleware(function (Middleware $middleware) {
        // Global: captura todas as requisições.
        $middleware->append(ImmutableLogMiddleware::class);
    })
    ->create();

// Laravel <= 10 — app/Http/Kernel.php
// protected $middleware = [
//     // ...
//     \App\Http\Middleware\ImmutableLogMiddleware::class,
// ];

Never hardcode the token. Set IMTBL_API_KEY in .env and ensure .env is in .gitignore.

How it works

handle()

Records request_id and start timestamp

next($request)

The app processes and the response is sent to the client

terminate()

Runs after the response — builds and sends the event

Custom event and trail

Set the `imtbl.event_name` and `imtbl.trail` request attributes in any controller. `terminate()` reads these values when building the event.

php
<?php
use Illuminate\Http\Request;

class PaymentController
{
    public function store(Request $request)
    {
        // Sobrescreve o nome do evento e agrupa numa trilha auditavel.
        $request->attributes->set('imtbl.event_name', 'payment.created');
        $request->attributes->set('imtbl.trail', 'order-7782');

        // ... lógica de negócio / business logic ...

        return response()->json(['ok' => true]);
    }
}

Auto default: http.METHOD.path.

Immutable trail (immutable_trail)

A trail groups related events into a single auditable timeline. Set the `imtbl.trail` request attribute, or propagate it across services with the `X-Imtbl-Trail` header. The value goes through `sanitizeTrail` before sending.

php
Route::post('/flows/{id}/run', function (Request $request, string $id) {
    $request->attributes->set('imtbl.trail', "flow-{$id}");
    // ... business logic ...
    return response()->json(['status' => 'ok']);
});

The trail cannot be empty, exceed 256 characters, or contain `:` — violations return `400 invalid_immutable_trail`. `sanitizeTrail` fixes the value before sending.

Response and status codes

The ingestion API is asynchronous. Success returns 202 (new) or 200 (idempotent duplicate). Since the middleware runs in terminate(), these codes matter mostly if you send events manually.

StatusMeaning
202Event accepted and queued (new)
200Idempotency-Key already exists — duplicate: true
400Missing/empty Idempotency-Key or invalid_immutable_trail
403Inactive/expired subscription, scope or retention
413payload_too_large (server limit: 16KB)
429monthly_limit_exceeded — do not retry
503mempool_full — transient, retryable

meta fields

Beyond the payload, the meta object carries the fields the SIEM uses to normalize (ECS) and enrich the event. All meta values are strings.

Field in metaWhat it does in the SIEM
event_nameThe event label (e.g. http.GET.auth-me-user, Payment error) — the identifier shown in the listing. Becomes event.action and derives event.category (e.g. a name with login → authentication).
client_ipBecomes source.ip with maximum precedence and provenance client_asserted. See the section below.
immutable_trailBecomes imtbl.immutable_trail — groups related events for investigation (e.g. one order, one user).
typeEvent severity: error / warning / info / success. Colors the badge in the listing. (event_type is accepted as a synonym.)
service, env, request_idMetadata: indexed and queryable in the dashboard (search/filters).

client_ip — end-user IP

The problem it solves

Between the browser and the core there are proxies/ALB. The IP the core sees on the connection is the previous hop (the client's backend or an AWS proxy), not the user's. Without action, source.ip would be the proxy IP — useless for geo, threat and IP-based detection. (Real example: XFF arrived as 44.192.13.3 (AWS) while the user was 179.110.4.205.)

The solution

The client's backend is the only one that sees the browser's real IP — so it forwards that IP in meta.client_ip when calling POST /v1/events.

How the SIEM handles it

  • Validates it is an IP (v4/v6). A non-IP value is ignored — it does not drop the event.
  • Writes to source.ip with maximum precedence (see order below).
  • Stamps imtbl.source_ip_origin = "client_asserted" — the UI shows the “User IP” badge.
  • Feeds GeoIP, threat intel and IP-based detection rules.
source.ip precedence:client_ipX-Forwarded-For (1º hop)X-Real-IPconnection IP

Provenance and trust

client_ip is asserted by the tenant — the client's backend claims the IP, and it is spoofable by whoever controls that backend. However it is self-contained to the tenant (it never crosses another tenant's boundary). A threat/geo hit on a client_asserted value is a claim, not an edge observation.

How to obtain the IP in your backend

Take the first IP from X-Forwarded-For (closest to the user); as a fallback, use the connection IP.

php
function client_ip(): ?string {
    $xff = $_SERVER['HTTP_X_FORWARDED_FOR'] ?? '';
    if ($xff !== '') {
        return trim(explode(',', $xff)[0]); // primeiro hop = IP do usuario
    }
    return $_SERVER['REMOTE_ADDR'] ?? null;
}

$meta = ['event_name' => 'user.login', 'client_ip' => client_ip()];

Payload example

json
{
  "payload": "{\"user\":\"bob\",\"action\":\"login\"}",
  "meta": {
    "event_name": "user.login",
    "client_ip": "179.110.4.205",
    "immutable_trail": "user-bob"
  }
}

PII note: client_ip is PII and gets sealed into the immutable block (permanent). Decide consciously between forensic evidence and “right to be forgotten” before sending it.

This documentation reflects the current integration behavior. For questions or advanced integrations, contact the support team.