feat: handle get object by key with/without timestamp

app/Http/Controllers/V1/KeyValueController.php

@@ -5,6 +5,7 @@
 use App\Http\Controllers\Controller;
 use App\Http\Resources\KeyValueResource;
 use App\Interfaces\KeyValueServiceInterface;
+use Illuminate\Http\Request;
 use Illuminate\Http\Resources\Json\ResourceCollection;
 
 class KeyValueController extends Controller
@@ -20,4 +21,16 @@ public function index(): ResourceCollection
 
         return KeyValueResource::collection($data);
     }
+
+    /**
+     * Accept a key and return the corresponding latest value.
+     * When given a key AND a timestamp,return whatever the value of the key at the time was.
+     */
+    public function show(Request $request, string $key): KeyValueResource
+    {
+        $timestamp = $request->query('timestamp');
+        $data = $this->keyValueService->getValue($key, $timestamp);
+
+        return new KeyValueResource($data);
+    }
 }

app/Interfaces/KeyValueRepositoryInterface.php

@@ -4,5 +4,9 @@
 
 interface KeyValueRepositoryInterface
 {
+    public function getKeyLatest(string $key);
+
+    public function getByTimestamp(string $key, int $timestamp);
+
     public function getAll();
 }

app/Interfaces/KeyValueServiceInterface.php

@@ -4,5 +4,7 @@
 
 interface KeyValueServiceInterface
 {
+    public function getValue(string $key, ?string $timestamp = '');
+
     public function getAll();
 }

app/Repositories/DynamoDbKeyValueRepository.php

@@ -4,12 +4,27 @@
 
 use App\Interfaces\KeyValueRepositoryInterface;
 use App\Models\KeyValue;
+use BaoPham\DynamoDb\RawDynamoDbQuery;
 use Illuminate\Database\Eloquent\Collection;
 
 class DynamoDbKeyValueRepository implements KeyValueRepositoryInterface
 {
     public function __construct(private KeyValue $model) {}
 
+    public function getKeyLatest(string $key)
+    {
+        // @phpstan-ignore-next-line
+        return $this->model->where('key', $key)
+            ->decorate(function (RawDynamoDbQuery $raw) {
+                $raw->query['ScanIndexForward'] = false;
+            })->firstOrFail();
+    }
+
+    public function getByTimestamp(string $key, int $timestamp)
+    {
+        return $this->model->findOrFail(['key' => $key, 'timestamp' => $timestamp]);
+    }
+
     public function getAll(): Collection
     {
         return $this->model->all();

app/Services/KeyValueService.php

@@ -9,6 +9,17 @@ class KeyValueService implements KeyValueServiceInterface
 {
     public function __construct(private KeyValueRepositoryInterface $keyValueRepository) {}
 
+    public function getValue(string $key, ?string $timestamp = '')
+    {
+        if ($timestamp) {
+            $data = $this->keyValueRepository->getByTimestamp($key, (int) $timestamp);
+        } else {
+            $data = $this->keyValueRepository->getKeyLatest($key);
+        }
+
+        return $data;
+    }
+
     public function getAll()
     {
         return $this->keyValueRepository->getAll();

routes/api.php

@@ -9,3 +9,4 @@
 })->middleware('auth:sanctum');
 
 Route::get('get_all_records', [KeyValueController::class, 'index']);
+Route::get('object/{key}', [KeyValueController::class, 'show']);

tests/Feature/Controllers/V1/KeyValueControllerTest.php

@@ -35,3 +35,30 @@
             ],
         ]);
 });
+
+it('can fetch the latest value for a key', function () {
+    $response = $this->get('/api/v1/object/mykey');
+
+    $response->assertStatus(200)
+        ->assertJson([
+            'data' => [
+                'key' => 'mykey',
+                'value' => 'latest_value',
+            ],
+        ]);
+});
+
+it('can fetch the value for a key at a specific timestamp', function () {
+    $timestamp = 1625236523;
+
+    $response = $this->get('/api/v1/object/mykey?timestamp=' . $timestamp);
+
+    $response->assertStatus(200)
+        ->assertJson([
+            'data' => [
+                'key' => 'mykey',
+                'value' => 'value1',
+                'timestamp' => $timestamp,
+            ],
+        ]);
+});

tests/Unit/Repositories/DynamoDbKeyValueRepositoryTest.php

@@ -11,6 +11,26 @@
     $this->repository = new DynamoDbKeyValueRepository($this->mockModel);
 });
 
+it('can get the latest value for a key', function () {
+    $mockedKeyValue = new KeyValue(['key' => 'test_key', 'value' => 'latest_value']);
+
+    $this->mockModel->shouldReceive('where')->once()->with('key', 'test_key')->andReturnSelf();
+    $this->mockModel->shouldReceive('decorate')->once()->andReturnSelf();
+    $this->mockModel->shouldReceive('firstOrFail')->once()->andReturn($mockedKeyValue);
+
+    $result = $this->repository->getKeyLatest('test_key');
+
+    expect($result)->toBe($mockedKeyValue);
+});
+
+it('throws ModelNotFoundException when getting by timestamp for non-existing key and timestamp', function () {
+    $this->mockModel->shouldReceive('findOrFail')->once()->andThrow(ModelNotFoundException::class);
+
+    $this->expectException(ModelNotFoundException::class);
+
+    $this->repository->getByTimestamp('non_existing_key', time());
+});
+
 it('can get all key-value pairs', function () {
     $mockedCollection = new Collection([
         new KeyValue(['key' => 'key1', 'value' => 'value1']),

tests/Unit/Services/KeyValueServiceTest.php

@@ -2,12 +2,30 @@
 
 use App\Interfaces\KeyValueRepositoryInterface;
 use App\Services\KeyValueService;
+use Carbon\CarbonImmutable;
 
 beforeEach(function () {
     $this->mockRepository = mock(KeyValueRepositoryInterface::class);
     $this->service = new KeyValueService($this->mockRepository);
 });
 
+it('can get the latest value for a key', function () {
+    $this->mockRepository->shouldReceive('getKeyLatest')->once()->with('test_key')->andReturn('latest_value');
+
+    $result = $this->service->getValue('test_key');
+
+    expect($result)->toBe('latest_value');
+});
+
+it('can get the value for a key at a specific timestamp', function () {
+    $timestamp = CarbonImmutable::now('UTC')->timestamp;
+    $this->mockRepository->shouldReceive('getByTimestamp')->once()->with('test_key', $timestamp)->andReturn('value_at_timestamp');
+
+    $result = $this->service->getValue('test_key', (string) $timestamp);
+
+    expect($result)->toBe('value_at_timestamp');
+});
+
 it('can get all key-value pairs', function () {
     $this->mockRepository->shouldReceive('getAll')->once()->andReturn(['key1' => 'value1', 'key2' => 'value2']);