#!/usr/bin/env node
/**
* @file Reddit MCP HTTP server implementation
* @module reddit-mcp-server
*
* @remarks
* This module implements the HTTP server that handles OAuth authentication
* and hosts the MCP endpoints. It provides:
* - OAuth2 authorization flow for Reddit authentication
* - MCP protocol endpoints for client communication
* - Session management and security
* - Health check and utility endpoints
*
* The server uses Express.js and implements proper CORS handling for
* cross-origin requests from MCP clients.
*
* @see {@link https://modelcontextprotocol.io/specification/2025-06-18/core/architecture} MCP Architecture
* @see {@link https://github.com/reddit-archive/reddit/wiki/OAuth2} Reddit OAuth2
*/
import express from 'express';
import cors from 'cors';
import cookieParser from 'cookie-parser';
import crypto from 'crypto';
import { CONFIG, VALID_REDIRECT_URIS } from './server/config';
import { OAuthServer } from './server/oauth-server';
import { setupMCPRoutes, setupUtilityRoutes } from './server/routes';
// Polyfill for jose library
if (typeof globalThis.crypto === 'undefined') {
// @ts-ignore
globalThis.crypto = crypto.webcrypto as any;
}
/**
* Main HTTP server class for the Reddit MCP server
*
* @remarks
* This class sets up and manages the Express.js server that handles:
* - OAuth authentication flows
* - MCP protocol endpoints
* - Session management
* - Health checks
*
* The server supports both local development and production deployment
* on platforms like Smithery.
*
* @example
* ```typescript
* const server = new RedditMCPServer();
* await server.start(3000);
* // Server now listening on port 3000
* ```
*/
export class RedditMCPServer {
private readonly app: express.Application;
private readonly oauthServer: OAuthServer;
constructor() {
this.app = express();
// Initialize OAuth server
this.oauthServer = new OAuthServer({
REDDIT_CLIENT_ID: CONFIG.REDDIT_CLIENT_ID,
REDDIT_CLIENT_SECRET: CONFIG.REDDIT_CLIENT_SECRET,
JWT_SECRET: CONFIG.JWT_SECRET,
OAUTH_ISSUER: CONFIG.OAUTH_ISSUER,
REDIRECT_URL: CONFIG.REDIRECT_URL,
REDDIT_USER_AGENT: CONFIG.REDDIT_USER_AGENT,
validRedirectUris: VALID_REDIRECT_URIS,
});
this.setupMiddleware();
this.setupRoutes();
}
private setupMiddleware(): void {
this.app.use(
cors({
origin: true,
credentials: true,
allowedHeaders: ['Content-Type', 'Authorization', 'Cache-Control', 'Accept'],
exposedHeaders: ['mcp-session-id', 'x-session-id'],
}),
);
this.app.use(cookieParser());
// Apply body parsing middleware selectively - NOT to MCP endpoints
// MCP uses streaming and must not have body parsing
this.app.use((req, res, next) => {
if (req.path === '/mcp') {
// Skip body parsing for MCP endpoint
next();
} else {
// Apply body parsing for all other endpoints
express.json()(req, res, (err) => {
if (err) return next(err);
express.urlencoded({ extended: true })(req, res, next);
});
}
});
}
private setupRoutes(): void {
this.oauthServer.setupRoutes(this.app);
setupMCPRoutes(this.app, this.oauthServer.authMiddleware());
setupUtilityRoutes(this.app);
}
public async start(port: number = 3000): Promise<void> {
this.app.listen(port, '0.0.0.0', () => {
console.log(`🚀 Reddit MCP Server running on port ${port}`);
console.log(`🔐 OAuth authorize: ${CONFIG.OAUTH_ISSUER}/oauth/authorize`);
console.log(`📡 MCP endpoint: ${CONFIG.OAUTH_ISSUER}/mcp`);
console.log(`❤️ Health: ${CONFIG.OAUTH_ISSUER}/health`);
});
}
/**
* Gets the underlying Express application instance
*
* @returns The Express application
*
* @remarks
* This method is useful for testing or extending the server
* with additional middleware or routes.
*/
public getExpressApp(): express.Application {
return this.app;
}
}
/**
* Main execution function for standalone mode
*
* @remarks
* Creates and starts the server using the port from configuration.
* This function is called when the module is executed directly.
*
* @internal
*/
async function main() {
const server = new RedditMCPServer();
await server.start(parseInt(CONFIG.PORT, 10));
}
// Run the server in standalone mode if executed directly
const isMainModule = process.argv[1] && process.argv[1].endsWith('reddit-mcp-server.ts');
if (isMainModule) {
main().catch((error) => {
console.error('Fatal error:', error);
process.exit(1);
});
}
// Export for external use
export default RedditMCPServer;
