// Main Express server for SilverBullet MCP
import express from 'express';
import { randomUUID } from 'node:crypto';
import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
import { PORT, validateConfiguration, logConfiguration, logStartupSuccess } from './config.js';
import { mcpAuthMiddleware } from './middleware.js';
import { configureMcpServerInstance } from './mcp-server.js';
const app = express();
app.use(express.json());
// Map to store transports by session ID
const transports: { [sessionId: string]: StreamableHTTPServerTransport } = {};
// Map to store MCP server instances by session ID
const mcpServers: { [sessionId: string]: McpServer } = {};
// Default route - no authentication required
app.get('/', (req, res) => {
res.json({
service: 'SilverBullet MCP Server',
version: '0.1.0',
status: 'running',
authentication: 'required for /mcp routes',
timestamp: new Date().toISOString(),
});
});
// Apply auth middleware to all /mcp routes only
app.use('/mcp', mcpAuthMiddleware);
// Handle POST requests for client-to-server communication
app.post('/mcp', async (req, res) => {
const sessionId = req.headers['mcp-session-id'] as string | undefined;
let transport: StreamableHTTPServerTransport;
let mcpServer: McpServer;
if (sessionId && transports[sessionId] && mcpServers[sessionId]) {
transport = transports[sessionId];
mcpServer = mcpServers[sessionId];
} else {
// Create new session
const newSessionId = randomUUID();
transport = new StreamableHTTPServerTransport({
sessionIdGenerator: () => newSessionId,
onsessioninitialized: (sId) => {
transports[sId] = transport;
mcpServers[sId] = mcpServer;
},
});
mcpServer = new McpServer({
name: 'SilverBullet MCP',
version: '0.1.0',
});
configureMcpServerInstance(mcpServer);
transport.onclose = () => {
if (transport.sessionId) {
delete transports[transport.sessionId];
delete mcpServers[transport.sessionId];
mcpServer.close();
}
};
await mcpServer.connect(transport);
}
try {
await transport.handleRequest(req, res, req.body);
} catch (error) {
console.error(`[POST /mcp] Error handling MCP request:`, error);
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error during request handling.',
},
id: req.body?.id || null,
});
}
}
});
// Reusable handler for GET and DELETE requests
const handleSessionRequest = async (
req: express.Request,
res: express.Response
) => {
const sessionId = req.headers['mcp-session-id'] as string | undefined;
if (!sessionId || !transports[sessionId]) {
res.status(400).send('Invalid or missing session ID');
return;
}
const transport = transports[sessionId];
try {
await transport.handleRequest(req, res);
} catch (error) {
console.error(`[handleSessionRequest] Error handling session event:`, error);
if (!res.headersSent) {
res.status(500).send('Internal server error during session event handling.');
} else {
res.end();
}
}
};
// Handle GET requests for server-to-client notifications via SSE
app.get('/mcp', (req, res) => {
handleSessionRequest(req, res);
});
// Handle DELETE requests for session termination
app.delete('/mcp', async (req: express.Request, res: express.Response) => {
const sessionId = req.headers['mcp-session-id'] as string | undefined;
if (!sessionId || !transports[sessionId]) {
res.status(400).send('Invalid or missing session ID for DELETE');
return;
}
const transport = transports[sessionId];
const mcpServer = mcpServers[sessionId];
try {
await transport.handleRequest(req, res);
} catch (error) {
console.error(`[DELETE /mcp] Error during DELETE handling:`, error);
if (!res.headersSent) {
res.status(500).send('Internal server error during session termination.');
}
} finally {
if (mcpServer) {
mcpServer.close();
}
if (transport) {
transport.close();
}
if (sessionId) {
delete transports[sessionId];
delete mcpServers[sessionId];
}
if (!res.headersSent) {
res.status(204).send();
} else if (!res.writableEnded) {
res.end();
}
}
});
// Validate configuration and start server
validateConfiguration();
logConfiguration();
app.listen(PORT, () => {
logStartupSuccess();
});
