Serverless MCP

import middy, { MiddyfiedHandler } from '@middy/core'; import { getInternal } from '@middy/util'; import { PreTokenGenerationV2TriggerEvent } from 'aws-lambda'; import createError from 'http-errors'; import { createTenantMiddleware, lambdaHandler, MiddlewareContext, MiddlewareHandler, } from './handler.js'; import httpErrorHandler from '@middy/http-error-handler'; export type MiddlewarePreTokenGenerationTriggerHandler = MiddlewareHandler<PreTokenGenerationV2TriggerEvent>; export type MiddyfiedMiddlewarePreTokenGenerationTriggerHandler = MiddyfiedHandler< PreTokenGenerationV2TriggerEvent, unknown, Error, MiddlewareContext >; export const preTokenGeneration = (): middy.MiddlewareObj => ({ before: async (request) => { const { callerContext: { clientId }, request: { userAttributes: { email, sub }, }, triggerSource, } = request.event as PreTokenGenerationV2TriggerEvent; if (!email) { throw new Error('no email given'); } if (!sub) { throw new Error('no sub given'); } Object.assign(request.internal, { clientId, email, sub, triggerSource, }); Object.assign(request.context, { cognito: { ...(await getInternal(['clientId'], request)), ...(await getInternal(['email'], request)), ...(await getInternal(['sub'], request)), ...(await getInternal(['triggerSource'], request)), }, }); }, }); const getTenantIdFromEvent = (event: PreTokenGenerationV2TriggerEvent) => { const { callerContext: { clientId }, } = event; if (!clientId) { throw createError(401, 'no tenant id given'); } return clientId; }; /** * Middleware for extracting the tenant ID from Pre Token Generation event. * Adds the tenant ID to the internal state and to the request context. * * @template TResult - The return type of the Lambda handler, defaults to void * @returns {middy.MiddlewareObj} A Middy middleware object with a 'before' hook * @throws {Error} Throws a 401 error if no tenant ID is found in the event */ const tenant = <TResult = void>(): middy.MiddlewareObj< PreTokenGenerationV2TriggerEvent, TResult > => createTenantMiddleware(getTenantIdFromEvent); /** * Creates a Pre Token Generation middleware handler. * This middleware handler includes logging, metrics, tracing, tenant extraction, STS role assumption, and the Pre Token Generation middleware. * @returns {Array} An array of middleware functions */ export const preTokenGenerationHandler = (): Array< middy.MiddlewareObj<any> > => [...lambdaHandler(tenant), preTokenGeneration(), httpErrorHandler()];