redis-mcp-transport/dist/index.mjs

Redis-based transport layer for Model Context Protocol with SSE support

import { createClient } from 'redis';
import { randomUUID } from 'node:crypto';
import contentType from 'content-type';
import getRawBody from 'raw-body';
import { JSONRPCMessageSchema } from '@modelcontextprotocol/sdk/types.js';

// 订阅端实现
class RedisMcpTransport {
    constructor(endpoint, resOrSessionId, redisURL) {
        this._endpoint = endpoint;
        this._redisClient = createClient({ url: redisURL });
        this._redisClient.on('error', (err) => console.error('Redis Client Error', err));
        this._isStarted = false;
        if (typeof resOrSessionId === 'string') {
            this._sessionId = resOrSessionId;
        }
        else {
            this._sseResponse = resOrSessionId;
            this._sessionId = randomUUID();
        }
    }
    async start() {
        if (!this._isStarted) {
            await this._redisClient.connect();
            this._isStarted = true;
        }
        if (this._sseResponse) {
            // 创建单独的订阅客户端
            // 订阅客户端直接操作this._ssrResponse不走onmessage逻辑
            this._subscriberClient = this._redisClient.duplicate();
            await this._subscriberClient.connect();
            const channel = this.getChannelName();
            console.debug('Subscribing to channel:', channel);
            await this._subscriberClient.subscribe(channel, (message) => {
                var _a;
                try {
                    const data = JSON.parse(message);
                    (_a = this._sseResponse) === null || _a === void 0 ? void 0 : _a.write(`event: message\ndata: ${JSON.stringify(data)}\n\n`);
                }
                catch (error) {
                    console.error('Error handling SSE message:', error);
                }
            });
            this._sseResponse.writeHead(200, {
                "Content-Type": "text/event-stream",
                "Cache-Control": "no-cache",
                Connection: "keep-alive",
            });
            this._sseResponse.write(`event: endpoint\ndata: ${encodeURI(this._endpoint)}?sessionId=${this._sessionId}\n\n`);
        }
    }
    /**
     * 实现与 SSEServerTransport 兼容的 handlePostMessage 方法
     * @param {Object} req - HTTP 请求对象（不使用，保持接口一致）
     * @param {Object} res - HTTP 响应对象（不使用，保持接口一致）
     * @returns {Promise<void>}
     */
    async handlePostMessage(req, res) {
        var _a;
        // 发布客户端处理handlePostMessage，走onmessage逻辑会触发transport的send方法，始终往redis channel发布消息
        try {
            // @ts-ignore
            let message = req.body;
            if (!message) {
                const contentTypeHeader = req.headers['content-type'];
                const ct = contentType.parse(contentTypeHeader);
                if (ct.type !== 'application/json') {
                    throw new Error('Unsupported content type');
                }
                let body = await getRawBody(req, { encoding: ct.parameters.charset || 'utf-8' });
                message = JSON.parse(body);
            }
            // const message: any = JSON.parse(body);
            const parsedMessage = JSONRPCMessageSchema.parse(message);
            (_a = this.onmessage) === null || _a === void 0 ? void 0 : _a.call(this, parsedMessage);
        }
        catch (error) {
            console.error('Error in handlePostMessage:', error);
            throw error;
        }
    }
    // 走一遍server的onmessage逻辑会触发transport的send方法
    async send(message) {
        if (!this._isStarted) {
            await this._redisClient.connect();
            this._isStarted = true;
        }
        const channel = this.getChannelName();
        await this._redisClient.publish(channel, JSON.stringify(message));
        await this.close();
    }
    async close() {
        if (this._subscriberClient) {
            const channel = this.getChannelName();
            await this._subscriberClient.unsubscribe(channel);
            await this._subscriberClient.disconnect();
        }
        if (this._isStarted) {
            await this._redisClient.disconnect();
            this._isStarted = false;
        }
    }
    getSessionId() {
        return this._sessionId;
    }
    getChannelName() {
        return `sse:channel:${this._sessionId}`;
    }
}

export { RedisMcpTransport, RedisMcpTransport as default };
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