# Server
This directory contains server infrastructure components for HTTP/SSE streaming and MCP protocol support.
## š Files
- **`cors.ts`** - CORS middleware configuration for cross-origin requests
- **`json-rpc.ts`** - JSON-RPC 2.0 protocol handler for MCP communication
## šÆ Purpose
The server module provides:
1. **HTTP/SSE Streaming** - Real-time data streaming support
2. **CORS Configuration** - Cross-origin request handling
3. **JSON-RPC Protocol** - MCP communication protocol
4. **Error Handling** - Standardized error responses
5. **Transport Layer** - Abstraction for stdio and HTTP transports
## š Components
### CORS Middleware (`cors.ts`)
Handles cross-origin requests for HTTP/SSE transport:
```typescript
import { configureCORS } from './server/cors'
// Configure CORS for Express app
configureCORS(app)
```
**Features:**
- Allows all origins in development
- Configurable origin whitelist for production
- Pre-flight request handling
- Custom headers support
### JSON-RPC Handler (`json-rpc.ts`)
Implements JSON-RPC 2.0 protocol for MCP:
```typescript
import { handleJSONRPC } from './server/json-rpc'
// Process JSON-RPC request
const response = await handleJSONRPC(request, mcpServer)
```
**Features:**
- Request/response validation
- Method routing (tools, prompts, resources)
- Error code standardization
- Batch request support
## š Transport Support
The server supports multiple transport modes:
### 1. stdio Transport (Default)
Standard input/output for direct MCP client integration:
```bash
node dist/index.js
```
### 2. HTTP/SSE Transport
HTTP server with Server-Sent Events for real-time streaming:
```bash
MCP_TRANSPORT=http MCP_PORT=3000 node dist/index.js
```
## šļø Architecture
```
server/
āāā cors.ts - CORS middleware
āāā json-rpc.ts - JSON-RPC 2.0 handler
```
## š Request Flow
```
Client Request
ā
CORS Middleware (HTTP only)
ā
JSON-RPC Handler
ā
MCP Server (tools/prompts/resources)
ā
Response Formatter
ā
Client Response
```
## š§ Configuration
### Environment Variables
- `MCP_TRANSPORT` - Transport mode (`stdio` or `http`, default: `stdio`)
- `MCP_PORT` - HTTP server port (default: `3000`)
- `ALLOWED_ORIGINS` - Comma-separated list of allowed CORS origins
### Example Configuration
```bash
# HTTP/SSE mode with custom port
MCP_TRANSPORT=http
MCP_PORT=8080
ALLOWED_ORIGINS=http://localhost:3000,https://app.example.com
```
## š Usage Example
```typescript
import { McpServer } from '@nullshot/mcp'
import { configureCORS } from './server/cors'
import { handleJSONRPC } from './server/json-rpc'
// Create MCP server
const server = new McpServer()
// Configure HTTP transport
if (transport === 'http') {
const app = express()
configureCORS(app)
app.post('/mcp', async (req, res) => {
const response = await handleJSONRPC(req.body, server)
res.json(response)
})
}
```
## š”ļø Security
- CORS origin validation
- Request size limits
- Rate limiting (recommended for production)
- Input sanitization via JSON-RPC validation
## š Future Enhancements
- WebSocket transport
- Authentication middleware
- Request logging and metrics
- Response compression
- SSL/TLS support
---
**Note**: Server components are internal infrastructure. They support both stdio and HTTP/SSE transports for MCP protocol.
