README

Laravel Idempotent is a lightweight middleware package to make POST, PUT, and PATCH requests idempotent.
It prevents duplicate processing (e.g., double orders, repeated payments, or accidental form resubmissions).

Features

• Automatic generation of idempotency keys based on request path + payload.
• Optional manual idempotency via Idempotency-Key header.
• Configurable modes:
  • replay – return cached response for duplicate requests
  • block – return HTTP status 409 or configured status
• Cache-based storage (supports cache or redis).
• Route-specific middleware; no need to apply globally.
• Logging support for debugging duplicate requests.

Installation

Install via Composer:

composer require nishit/laravel-idempotent

Publish the configuration file:

php artisan vendor:publish --provider="Nishit\LaravelIdempotent\LaravelIdempotentServiceProvider" --tag=config

Configuration

Edit the published config/idempotent.php:

return [
    'ttl' => 3600,                   // Cache duration in seconds
    'storage' => 'cache',            // 'cache' or 'redis'
    'duplicate_response' => 409,     // HTTP status for duplicates in block mode
    'enable_logging' => env('APP_DEBUG', false),
    'mode' => 'replay',              // 'replay' or 'block'
];

Usage

Apply middleware to selected routes:

use App\Http\Controllers\OrderController;
use Illuminate\Support\Facades\Route;
use Illuminate\Http\Request;

// Single route
Route::post('/submit', function (\Illuminate\Http\Request $request) {
    return response()->json(['message' => 'Processed', 'data' => $request->all()]);
})->middleware('idempotent');

Route::post('/order', [OrderController::class, 'create'])->middleware('idempotent');

// Or group routes
Route::middleware(['idempotent'])->group(function () {
    Route::post('/order', [OrderController::class, 'create']);
});

Only routes using the middleware will have idempotency applied. Other routes remain unaffected.

How It Works

1. Middleware generates a unique key per request using:

   • Request path
   • Request payload (POST / PUT / PATCH)
   • Optional Idempotency-Key header

2. If the key exists in cache:

   • Replay mode → returns cached response
   • Block mode → returns HTTP 409 or configured status

3. If the key does not exist, the request is processed and the response is cached for future duplicates.

Testing

Use curl to test idempotency:

# First request
curl -X POST http://127.0.0.1:8000/api/submit \
  -H "Content-Type: application/json" \
  -d '{"name":"John","email":"john@example.com"}'

# Repeat request with same payload or manual Idempotency-Key header
curl -X POST http://127.0.0.1:8000/api/submit \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 123456" \
  -d '{"name":"John","email":"john@example.com"}'

• In replay mode, the second request returns the cached response.
• In block mode, the second request returns HTTP 409 (or the configured status).

Logging

Enable logging in config/idempotent.php:

'enable_logging' => true,

Duplicate requests will be logged in storage/logs/laravel.log:

[2026-04-07 09:24:00] local.INFO: duplicate found {"key":"idempotent_<hash>"}

License

This package is open-sourced software licensed under the MIT License.