# Speedtest Application

A full-stack network speed testing application built with Bun.js.

## Architecture

- **Server**: Single Bun.js HTTP server serving both frontend and APIs
- **Frontend**: HTML/JavaScript client served at `/` for running speed tests
- **Configuration**: Maximum request body size set to 3GB for large file uploads
- **APIs**:
  - `GET /` - Speedtest frontend UI
  - `GET /_health/readiness` - Health check
  - `GET /data?size=<bytes>` - Download random test data
  - `POST /data?requestId=<id>` - Upload data for validation

## Quick Start

### 1. Start the Server
```bash
bun run start
```
Server will start on `http://localhost:8080` with both backend APIs and frontend served from the same server.

### 2. Run Speed Test
1. Open `http://localhost:8080` in your browser
2. Select test size (1MB - 50MB)
3. Click "Start Speed Test"
4. View download/upload speeds and validation results

## Development

### Run Both Servers Simultaneously
```bash
# Requires concurrently (npm install -D concurrently)
bun run dev
```

### Manual Testing

Test the API directly:
```bash
# Health check
curl http://localhost:8080/_health/readiness

# Download test (1MB)
curl -o test.dat http://localhost:8080/data?size=1048576

# Upload same data back (get requestId from previous response headers)
curl -X POST "http://localhost:8080/data?requestId=<request-id>" \
  --data-binary @test.dat \
  -H "Content-Type: application/octet-stream"
```

## Speed Test Workflow

1. **Download Phase**: Frontend downloads random data from server
2. **Upload Phase**: Frontend uploads the same data back for validation
3. **Validation**: Server verifies data integrity and measures performance
4. **Results**: Frontend displays download/upload speeds, total time, and data integrity status

## Features

- ✅ Configurable test sizes (1MB - 2.5GB)
- ✅ Large file support (up to 3GB request body limit)
- ✅ Real-time progress indicators
- ✅ Data integrity validation with SHA256
- ✅ Upload/download speed measurements
- ✅ Clean, responsive UI
- ✅ Comprehensive logging
- ✅ Error handling and recovery

## API Reference

### GET /data
Downloads random test data for speed testing.

**Query Parameters:**
- `size` (number): Size in bytes (default: 10MB)

**Response Headers:**
- `Content-Type`: `application/octet-stream`
- `Content-Length`: Data size
- `Content-Hash`: SHA256 hash
- `X-Request-ID`: Unique request identifier

### POST /data
Uploads data for validation and performance measurement.

**Query Parameters:**
- `requestId` (string): Request ID from download phase

**Response:**
```json
{
  "requestId": "uuid",
  "valid": true,
  "expectedHash": "sha256...",
  "receivedHash": "sha256...",
  "size": 1048576,
  "totalTimeMs": 1250,
  "dataRateBps": 838860.8,
  "dataRateMbps": 6.71,
  "timestamp": "2024-01-01T12:00:00.000Z"
}
```

### GET /_health/readiness
Health check endpoint.

**Response:**
```json
{
  "status": "ok",
  "timestamp": "2024-01-01T12:00:00.000Z",
  "uptime": 123.45,
  "memory": {...},
  "cpu": [...],
  "os": "darwin"
}
```