api-gateway

API Gateway with Authentication and Response Transformation

Every incoming API request needs authentication, routing to the right backend, and response transformation before it reaches the client. Without a gateway, each service duplicates auth logic and clients get inconsistent response formats. This workflow authenticates the caller, routes the request, transforms the response per client tier, and sends it back.

Workflow

endpoint, method, payload
          |
          v
+--------------------+     +--------------------+     +---------------------------+     +--------------------+
| ag_authenticate    | --> | ag_route_request   | --> | ag_transform_response     | --> | ag_send_response   |
+--------------------+     +--------------------+     +---------------------------+     +--------------------+
  clientId:                  statusCode: 200           transformed response            final response with
  client-enterprise-01       backendLatency: 45ms      per client tier                 headers & caching
  tier: premium
  rateLimit: 10000

Workers

AgAuthenticateWorker -- Validates the API key. Returns clientId: "client-enterprise-01", tier: "premium", and rateLimit: 10000.

RouteRequestWorker -- Routes the method + endpoint to the backend. Returns statusCode: 200 with backendLatency: 45ms and the raw response.

TransformResponseWorker -- Transforms the response for the client's tier level.

SendResponseWorker -- Sends the final response with status code, body, and headers.

Tests

4 unit tests cover authentication, routing, transformation, and response delivery.

Running

See ../../RUNNING.md for setup and execution instructions.