/**
* Request/response utilities for HTTP layer
*/
import { isInitializeRequest } from "@modelcontextprotocol/sdk/types.js";
import { createSessionError } from "@utils/errors.js";
import type { Request, Response } from "express";
/**
* Extract session ID from request headers
*/
export function getSessionId(req: Request): string | undefined {
return req.headers["mcp-session-id"] as string | undefined;
}
/**
* Check if request has valid session ID
*/
export function hasSessionId(req: Request): boolean {
const sessionId = getSessionId(req);
return sessionId !== undefined && sessionId.trim().length > 0;
}
/**
* Validate session ID exists and is not empty
*/
export function validateSessionId(req: Request): string {
const sessionId = getSessionId(req);
if (!sessionId || sessionId.trim().length === 0) {
throw createSessionError("Missing or empty session ID");
}
return sessionId;
}
/**
* Check if request is a new initialization request
*/
export function isNewInitializeRequest(req: Request): boolean {
return !hasSessionId(req) && isInitializeRequest(req.body);
}
/**
* Check if request is a session continuation request
*/
export function isSessionContinuation(req: Request): boolean {
return hasSessionId(req);
}
/**
* Validate request for MCP processing
*/
export function validateMcpRequest(req: Request): {
isInitialize: boolean;
sessionId?: string;
} {
const isInitialize = isNewInitializeRequest(req);
const isSession = isSessionContinuation(req);
if (!isInitialize && !isSession) {
throw createSessionError(
"Bad Request: No valid session ID provided and not an initialize request",
);
}
return {
isInitialize,
sessionId: isSession ? validateSessionId(req) : undefined,
};
}
/**
* Send session error response
*/
export function sendSessionError(res: Response, message: string): void {
res.status(400).json({
jsonrpc: "2.0",
error: {
code: -32001,
message,
},
id: null,
});
}
/**
* Send invalid request error response
*/
export function sendInvalidRequestError(res: Response, message: string): void {
res.status(400).json({
jsonrpc: "2.0",
error: {
code: -32000,
message,
},
id: null,
});
}
/**
* Extract JSON-RPC request ID if available
*/
export function getRequestId(req: Request): string | number | null {
if (req.body && typeof req.body === "object" && "id" in req.body) {
return req.body.id as string | number;
}
return null;
}
/**
* Check if request has valid JSON-RPC format
*/
export function isValidJsonRpc(req: Request): boolean {
return (
req.body &&
typeof req.body === "object" &&
req.body.jsonrpc === "2.0" &&
"method" in req.body
);
}
