mcp-simple-gateway/dist/services/SSEMcpProxy.js

MCP Simple Gateway

import { getRPCErrorFromError } from '../helpers/index.js';
export class SSEMcpProxy {
    serverTransport;
    proxyTransport;
    logger;
    constructor(params) {
        this.serverTransport = params.serverTransport;
        this.proxyTransport = params.proxyTransport;
        this.logger = params.logger;
    }
    get sessionId() {
        return this.proxyTransport.sessionId;
    }
    start = async () => {
        await this.serverTransport.start();
        await this.proxyTransport.start();
        this.serverTransport.onmessage = (msg) => {
            this.proxyTransport.send(msg);
        };
        this.serverTransport.onerror = async (err) => {
            const rpcError = getRPCErrorFromError(err);
            try {
                await this.proxyTransport.send(rpcError);
            }
            catch (error) {
                this.logger?.error(error, 'Failed to send error');
            }
        };
        this.proxyTransport.onmessage = async (msg) => {
            try {
                await this.serverTransport.send(msg);
            }
            catch (error) {
                const rpcError = getRPCErrorFromError(error);
                await this.proxyTransport.send({
                    ...rpcError,
                    id: rpcError.id || msg.id,
                });
            }
        };
    };
    handleMessage = (req, res, parsedBody) => {
        return this.proxyTransport.handlePostMessage(req, res, parsedBody);
    };
    close = async () => {
        await this.serverTransport.close();
        await this.proxyTransport.close();
    };
}