# Test Infrastructure: REST API Server (Flask)

## Overview

The test REST API server is a lightweight Python/Flask application that provides HTTP endpoints matching the patterns used by ScadaLink's External System Gateway and Inbound API components. It supports simple parameter/response methods, complex nested object/list methods, authentication, and error simulation.

## Image & Ports

- **Image**: Custom build from `infra/restapi/Dockerfile` (Python 3.13 + Flask)
- **API port**: 5200

## Configuration

| Setting | Value | Description |
|---------|-------|-------------|
| `API_NO_AUTH` | `0` | Set to `1` to disable API key authentication |
| `PORT` | `5200` | Server listen port |

## Authentication

The server validates requests using one of two methods:

- **API Key**: `X-API-Key: scadalink-test-key-1` header
- **Basic Auth**: Any username/password (accepts all credentials)

The `GET /api/Ping` endpoint is always unauthenticated (health check).

Auth can be disabled entirely by setting `API_NO_AUTH=1` in the Docker Compose environment or passing `--no-auth` when running directly.

For `appsettings.Development.json` (External System Gateway):

```json
{
  "ExternalSystems": {
    "TestApi": {
      "BaseUrl": "http://localhost:5200",
      "AuthMode": "ApiKey",
      "ApiKey": "scadalink-test-key-1"
    }
  }
}
```

## Endpoints

### Simple Methods

| Method | Path | HTTP | Params | Response | Description |
|--------|------|------|--------|----------|-------------|
| Ping | `/api/Ping` | GET | — | `{"pong": true}` | Health check (no auth) |
| Add | `/api/Add` | POST | `{"a": 5, "b": 3}` | `{"result": 8}` | Add two numbers |
| Multiply | `/api/Multiply` | POST | `{"a": 4, "b": 7}` | `{"result": 28}` | Multiply two numbers |
| Echo | `/api/Echo` | POST | `{"message": "hello"}` | `{"message": "hello"}` | Echo back input |
| GetStatus | `/api/GetStatus` | POST | `{}` | `{"status": "running", "uptime": 123.4}` | Server status |

### Complex Methods (nested objects + lists)

| Method | Path | HTTP | Description |
|--------|------|------|-------------|
| GetProductionReport | `/api/GetProductionReport` | POST | Production report with line details |
| GetRecipe | `/api/GetRecipe` | POST | Recipe with ingredients list |
| SubmitBatch | `/api/SubmitBatch` | POST | Submit batch with items (complex input) |
| GetEquipmentStatus | `/api/GetEquipmentStatus` | POST | Equipment list with nested status objects |

### Error Simulation

| Method | Path | HTTP | Params | Description |
|--------|------|------|--------|-------------|
| SimulateTimeout | `/api/SimulateTimeout` | POST | `{"seconds": 5}` | Delay response (max 60s) |
| SimulateError | `/api/SimulateError` | POST | `{"code": 500}` | Return specified HTTP error (400–599) |

### Method Discovery

| Method | Path | HTTP | Description |
|--------|------|------|-------------|
| methods | `/api/methods` | GET | List all available methods with signatures |

## Response Examples

**GetProductionReport** (`{"siteId": "SiteA", "startDate": "2026-03-01", "endDate": "2026-03-16"}`):

```json
{
  "siteName": "Site SiteA",
  "totalUnits": 14250,
  "lines": [
    { "lineName": "Line-1", "units": 8200, "efficiency": 92.5 },
    { "lineName": "Line-2", "units": 6050, "efficiency": 88.1 }
  ]
}
```

**GetRecipe** (`{"recipeId": "R-100"}`):

```json
{
  "recipeId": "R-100",
  "name": "Standard Mix",
  "version": 3,
  "ingredients": [
    { "name": "Material-A", "quantity": 45.0, "unit": "kg" },
    { "name": "Material-B", "quantity": 12.5, "unit": "L" }
  ]
}
```

**SubmitBatch** (complex input with items list):

```json
{
  "siteId": "SiteA",
  "recipeId": "R-100",
  "items": [
    { "materialId": "MAT-001", "quantity": 45.0, "lotNumber": "LOT-2026-001" },
    { "materialId": "MAT-002", "quantity": 12.5, "lotNumber": "LOT-2026-002" }
  ]
}
```

Response: `{"batchId": "BATCH-A1B2C3D4", "accepted": true, "itemCount": 2}`

**GetEquipmentStatus** (`{"siteId": "SiteA"}`):

```json
{
  "siteId": "SiteA",
  "equipment": [
    {
      "equipmentId": "PUMP-001",
      "name": "Feed Pump A",
      "status": { "state": "running", "health": 98.5, "lastMaintenance": "2026-02-15" }
    },
    {
      "equipmentId": "TANK-001",
      "name": "Mix Tank 1",
      "status": { "state": "idle", "health": 100.0, "lastMaintenance": "2026-03-01" }
    },
    {
      "equipmentId": "CONV-001",
      "name": "Conveyor B",
      "status": { "state": "alarm", "health": 72.3, "lastMaintenance": "2026-01-20" }
    }
  ]
}
```

## Verification

1. Check the container is running:

```bash
docker ps --filter name=scadalink-restapi
```

2. Test the health endpoint:

```bash
curl http://localhost:5200/api/Ping
```

3. Test an authenticated call:

```bash
curl -X POST http://localhost:5200/api/Add \
  -H "X-API-Key: scadalink-test-key-1" \
  -H "Content-Type: application/json" \
  -d '{"a": 2, "b": 3}'
```

## CLI Tool

The `infra/tools/restapi_tool.py` script provides a CLI for interacting with the REST API server. This tool requires the `requests` library (included in `tools/requirements.txt`).

**Commands**:

```bash
# Check API server connectivity and status
python infra/tools/restapi_tool.py check

# Call a simple method
python infra/tools/restapi_tool.py call --method Add --params '{"a": 2, "b": 3}'

# Call a complex method
python infra/tools/restapi_tool.py call --method GetProductionReport --params '{"siteId": "SiteA", "startDate": "2026-03-01", "endDate": "2026-03-16"}'

# Simulate an error
python infra/tools/restapi_tool.py call --method SimulateError --params '{"code": 503}'

# List all available methods
python infra/tools/restapi_tool.py methods
```

Use `--url` to override the base URL (default: `http://localhost:5200`), `--api-key` for the API key. Run with `--help` for full usage.

## Relevance to ScadaLink Components

- **External System Gateway** — test HTTP/REST calls (`ExternalSystem.Call()` and `CachedCall()`), API key authentication, error classification (5xx vs 4xx), and timeout handling.
- **Inbound API** — test the `POST /api/{methodName}` pattern, flat JSON parameters, and extended type system (Object, List) with complex nested responses.
- **Store-and-Forward Engine** — verify buffered retry by using `SimulateError` to return transient errors (503, 408, 429) and observing store-and-forward behavior.

## Notes

- The server is stateless — no data persistence between container restarts.
- `SimulateTimeout` caps at 60 seconds to prevent accidental container hangs.
- `SimulateError` accepts codes 400–599; other values default to 500.
- `SubmitBatch` generates a unique `batchId` per call (UUID-based).
- The `/api/methods` endpoint provides machine-readable method discovery (useful for CLI tool and automated testing).
- To simulate connection failures for store-and-forward testing, stop the container: `docker compose stop restapi`. Restart with `docker compose start restapi`.