import "dotenv/config"
import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js"
import cors from "cors"
import express from "express"
import type { Request, Response } from "express"
import Logger from "@/utils/logger"
import { startServer } from "./base"
/**
* SSE-based MCP Server (Legacy)
*
* This is maintained for backwards compatibility.
* For ChatGPT Developer Mode, consider using the HTTP server instead.
*
* @deprecated Use startHTTPServer for new integrations
*/
export const startSSEServer = async () => {
try {
const app = express()
const server = startServer()
app.use(cors({
origin: "*",
methods: ["GET", "POST", "OPTIONS"],
allowedHeaders: ["Content-Type"]
}))
app.use(express.json())
// Log the current log level on startup
Logger.info(`Starting SSE server with log level: ${Logger.getLevel()}`)
// to support multiple simultaneous connections we have a lookup object from
// sessionId to transport
const transports: { [sessionId: string]: SSEServerTransport } = {}
// Health check endpoint
app.get("/health", (_: Request, res: Response) => {
res.json({
status: "healthy",
name: "Universal Crypto MCP",
version: "1.0.0",
transport: "sse",
sessions: Object.keys(transports).length,
timestamp: new Date().toISOString()
})
})
// Server info endpoint
app.get("/", (_: Request, res: Response) => {
res.json({
name: "Universal Crypto MCP",
version: "1.0.0",
description: "Universal MCP server for all EVM-compatible networks",
protocol: "mcp",
transport: "sse",
endpoints: {
sse: "/sse",
messages: "/messages",
health: "/health"
}
})
})
app.get("/sse", async (_: Request, res: Response) => {
const transport = new SSEServerTransport("/messages", res)
transports[transport.sessionId] = transport
Logger.info("New SSE connection established", {
sessionId: transport.sessionId
})
res.on("close", () => {
Logger.info("SSE connection closed", { sessionId: transport.sessionId })
delete transports[transport.sessionId]
})
try {
await server.connect(transport)
} catch (error) {
Logger.error("Error connecting transport", {
sessionId: transport.sessionId,
error
})
}
})
app.post("/messages", async (req: Request, res: Response) => {
const sessionId = req.query.sessionId as string
const transport = transports[sessionId]
if (transport) {
Logger.debug("Handling message", { sessionId, body: req.body })
try {
await transport.handlePostMessage(req, res, req.body)
} catch (error) {
Logger.error("Error handling message", { sessionId, error })
res.status(500).send("Internal server error")
}
} else {
Logger.warn("No transport found for session", { sessionId })
res.status(400).send("No transport found for sessionId")
}
})
const PORT = process.env.PORT || 3001
app.listen(PORT, () => {
Logger.info(`Universal Crypto MCP SSE Server running on http://localhost:${PORT}`)
Logger.info(`SSE endpoint: http://localhost:${PORT}/sse`)
})
return server
} catch (error) {
Logger.error("Error starting SSE Server:", error)
throw error
}
}
