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Merged
CodeWithCJ merged 1 commit into from
Feb 26, 2026
Merged

ported MCP to http stream instead of SSE #761

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14 changes: 7 additions & 7 deletions SparkyFitnessMCP/package-lock.json
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2 changes: 1 addition & 1 deletion SparkyFitnessMCP/package.json
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Expand Up @@ -18,7 +18,7 @@
"author": "CodewithCJ",
"license": "Refer to License.md",
"dependencies": {
"@modelcontextprotocol/sdk": "^1.0.0",
"@modelcontextprotocol/sdk": "^1.27.1",
"pg": "^8.11.0",
"express": "^4.18.2",
"dotenv": "^16.3.1",
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180 changes: 89 additions & 91 deletions SparkyFitnessMCP/src/index.ts
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@@ -1,12 +1,13 @@
import "./load_env.js"; // MUST BE FIRST

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
CallToolRequestSchema,
ListToolsRequestSchema,
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import {
CallToolRequestSchema,
ListToolsRequestSchema,
ErrorCode,
McpError
} from "@modelcontextprotocol/sdk/types.js";
import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
import express from "express";
import cors from "cors";

Expand All @@ -21,126 +22,123 @@ import { MOCK_USER_ID } from "./config.js";

console.error(`[MCP] Active Mock User ID: ${MOCK_USER_ID}`);

const handlers = [
handleNutritionTool,
handleExerciseTool,
handleCheckinTool,
handleCoachTool,
handleProactiveTool,
handleVisionTool,
handleDevTool,
];

const allTools = [
...nutritionTools,
...exerciseTools,
...checkinTools,
...coachTools,
...proactiveTools,
...visionTools,
...devTools,
];

/**
* Factory function to create a new MCP Server instance.
* Using the low-level Server class to support raw JSON schemas (McpServer defaults them to empty).
* Called once per request in stateless mode (SDK requirement).
*/
function createMCPServer() {
const server = new Server(
{
name: "sparky-fitness-mcp",
version: "1.0.0",
},
{
capabilities: {
tools: {},
},
}
{ name: "sparky-fitness-mcp", version: "1.0.0" },
{ capabilities: { tools: {} } }
);

// Register the tool listing handler
server.setRequestHandler(ListToolsRequestSchema, async () => {
return {
tools: [
...nutritionTools,
...exerciseTools,
...checkinTools,
...coachTools,
...proactiveTools,
...visionTools,
...devTools
],
tools: allTools.map(tool => ({
name: tool.name,
description: tool.description,
inputSchema: tool.inputSchema,
}))
};
});

server.setRequestHandler(CallToolRequestSchema, async (request: any) => {
// Register the tool calling handler
server.setRequestHandler(CallToolRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
const handlers = [
handleNutritionTool,
handleExerciseTool,
handleCheckinTool,
handleCoachTool,
handleProactiveTool,
handleVisionTool,
handleDevTool
];

for (const handler of handlers) {
const res = await handler(name, args);
if (res) return res;
const result = await handler(name, args);
if (result) return result;
}

throw new Error(`Unknown tool: ${name}`);
throw new McpError(
ErrorCode.MethodNotFound,
`Tool not found: ${name}`
);
});

return server;
}

const app = express();
app.use(cors());

// Map to store active SSE transports by their session ID
const transports = new Map<string, SSEServerTransport>();
app.use(express.json());

/**
* Optimized SSE Connection Handler
* MCP Streamable HTTP handler.
*
* IMPORTANT: The SDK's stateless transport CANNOT be reused across requests
* (it throws "Stateless transport cannot be reused across requests").
* We must create a fresh Server + transport per request.
*
* We also force-inject the correct Accept header so clients like n8n that only
* send "Accept: application/json" don't get a 406 from the SDK's strict validation
* (which requires BOTH application/json AND text/event-stream).
*/
const handleSseConnection = async (req: express.Request, res: express.Response) => {
console.log(`[MCP] New SSE connection: ${req.method} ${req.path}`);

const transport = new SSEServerTransport(req.path, res);
const server = createMCPServer();

await server.connect(transport);

if (transport.sessionId) {
transports.set(transport.sessionId, transport);
console.log(`[MCP] Session active: ${transport.sessionId}`);

res.on("close", () => {
console.log(`[MCP] Session closed: ${transport.sessionId}`);
transports.delete(transport.sessionId!);
server.close();
const handleMcpRequest = async (req: express.Request, res: express.Response) => {
console.log(`[MCP] Request: ${req.method} ${req.path}`);

// Force the Accept header to satisfy SDK validation.
req.headers['accept'] = 'application/json, text/event-stream';

try {
// Create a fresh server + transport per request (stateless mode requirement)
const server = createMCPServer();
const transport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined, // stateless mode
enableJsonResponse: true, // return JSON directly instead of SSE streams
});
}
};

/**
* Resilient Message Handler
*/
const handleSseMessage = async (req: express.Request, res: express.Response) => {
const sessionId = req.query.sessionId as string;

let transport = transports.get(sessionId);
if (!transport) {
console.log(`[MCP] Session ${sessionId} not found yet, retrying...`);
await new Promise(r => setTimeout(r, 200));
transport = transports.get(sessionId);
}
await server.connect(transport);
await transport.handleRequest(req, res, req.body);

if (transport) {
await transport.handlePostMessage(req, res);
} else {
const activeSessions = Array.from(transports.keys()).join(", ");
console.error(`[MCP] ERROR: Unknown session ${sessionId}. Active: [${activeSessions}]`);
res.status(404).send("Unknown session");
// Clean up after the response is sent
res.on("finish", () => {
transport.close().catch(() => {});
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@gemini-code-assist gemini-code-assist bot Feb 26, 2026

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medium

Swallowing errors with an empty catch block can hide potential issues during resource cleanup. It's better to at least log the error to aid in debugging if transport.close() fails for some reason.

Suggested change
transport.close().catch(() => {});
transport.close().catch(console.error);

});
} catch (error) {
console.error("[MCP] Transport error:", error);
if (!res.headersSent) {
res.status(500).json({
jsonrpc: "2.0",
error: { code: -32603, message: "Internal Server Error" },
id: null,
});
}
}
};

app.get("/mcp", handleSseConnection);
app.post("/mcp", handleSseMessage);
app.get("/sse", handleSseConnection);
app.post(["/sse", "/messages"], handleSseMessage);
app.all("/mcp", handleMcpRequest);

app.use(express.json());
// Simple tools discovery endpoint (no MCP protocol overhead)
app.get("/mcp/tools", (_req, res) => {
res.json({ tools: allTools });
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medium

This endpoint returns the entire tool objects from allTools. For consistency and to prevent accidentally exposing internal properties, it should return the same sanitized data as the ListTools MCP handler, which maps over the tools to select specific properties (name, description, inputSchema).

Suggested change
res.json({ tools: allTools });
res.json({ tools: allTools.map(tool => ({ name: tool.name, description: tool.description, inputSchema: tool.inputSchema })) });

});

const PORT = process.env.SPARKY_FITNESS_MCP_PORT || process.env.PORT || 5435;

if (process.stdout.isTTY || process.env.TRANSPORT === 'sse') {
app.listen(PORT, () => {
console.log(`Sparky MCP Server running on port ${PORT} (SSE mode)`);
});
} else {
const server = createMCPServer();
const transport = new StdioServerTransport();
server.connect(transport).catch(console.error);
console.error("Sparky MCP Server running in Stdio mode");
}
app.listen(PORT, () => {
console.log(`Sparky MCP Server running on port ${PORT} (Streamable HTTP mode)`);
});
4 changes: 2 additions & 2 deletions SparkyFitnessMCP/src/tests/logic_verification.ts
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Expand Up @@ -7,8 +7,8 @@ const __dirname = path.dirname(fileURLToPath(import.meta.url));
// Load environment variables from the root .env
dotenv.config({ path: path.resolve(__dirname, "../../../.env") });

import { handleNutritionTool } from "../tools/nutrition.js";
import { handleCoachTool } from "../tools/coach.js";
import { handleNutritionTool } from "../tools/food/index.js";
import { handleCoachTool } from "../tools/coach/index.js";
import { poolInstance } from "../db.js";

async function runTests() {
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36 changes: 35 additions & 1 deletion SparkyFitnessMCP/src/tools/food/database.ts
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Expand Up @@ -49,7 +49,41 @@ export const createFood = async (args: any) => {
]
);

return { content: [{ type: "text", text: `✅ Created food "${food_name}" with variant ID ${createVariantRes.rows[0].id}.` }] };
const newVariantId = createVariantRes.rows[0].id;
let message = `✅ Created food "${food_name}" (Variant ID: ${newVariantId}).`;

// Automatically log to diary if meal_type is provided
if (args.meal_type) {
const mealTypeId = await getMealTypeId(args.meal_type);
const date = args.entry_date || new Date().toISOString().split('T')[0];

// Final quantity/unit for the log entry
const logQuantity = parseFloat(args.quantity) || macros?.serving_size || 100;
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high

There's a potential bug here when args.quantity is 0. parseFloat('0') results in 0, which is a falsy value. This will cause the expression to incorrectly fall back to macros?.serving_size || 100 instead of using the provided quantity of 0. You should check for null or undefined explicitly to handle this case correctly.

Suggested change
const logQuantity = parseFloat(args.quantity) || macros?.serving_size || 100;
const logQuantity = args.quantity != null ? parseFloat(args.quantity) : (macros?.serving_size || 100);

const logUnit = args.unit || macros?.serving_unit || 'g';

await query(
`INSERT INTO food_entries (
user_id, food_id, variant_id, meal_type_id, quantity, unit, entry_date,
food_name, brand_name, calories, protein, carbs, fat, serving_size, serving_unit,
saturated_fat, polyunsaturated_fat, monounsaturated_fat, trans_fat, cholesterol,
sodium, potassium, dietary_fiber, sugars, vitamin_a, vitamin_c, calcium, iron,
glycemic_index, custom_nutrients, created_by_user_id
) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18, $19, $20, $21, $22, $23, $24, $25, $26, $27, $28, $29, $30, $1)`,
[
MOCK_USER_ID, newFoodId, newVariantId, mealTypeId,
logQuantity, logUnit, date,
food_name, brand || '', macros?.calories || 0, macros?.protein || 0, macros?.carbs || 0, macros?.fat || 0,
macros?.serving_size || 100, macros?.serving_unit || 'g',
macros?.saturated_fat || 0, macros?.polyunsaturated_fat || 0, macros?.monounsaturated_fat || 0, macros?.trans_fat || 0,
macros?.cholesterol || 0, macros?.sodium || 0, macros?.potassium || 0, macros?.fiber || 0, macros?.sugar || 0,
macros?.vitamin_a || 0, macros?.vitamin_c || 0, macros?.calcium || 0, macros?.iron || 0,
macros?.gi || 'None', macros?.custom_nutrients || {}
]
);
message += ` Also logged to ${args.meal_type} for ${date}.`;
}

return { content: [{ type: "text", text: message }] };
};

export const searchMeal = async (args: any) => {
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