Serverless Hero

Lee Gilmore leegilmorecode

Serverless Hero

leegilmorecode / get-order.ts

Created July 21, 2022 15:16

An example Lambda which is utilising Middy middeware through an attached Lambda Layer

	import {
	APIGatewayProxyEvent,
	APIGatewayProxyEventPathParameters,
	APIGatewayProxyHandler,
	APIGatewayProxyResult,
	} from "aws-lambda";
	import {
	hydrateContext,
	validateCompanyAccessMiddleware,
	validateTokenUserAccessMiddleware,

leegilmorecode / hydrate-context.ts

Created July 21, 2022 15:10

Lambda middleware using Middy which hydrates the user missions based on an external service

 import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";
 import { UserContext } from "../../../types";
 import axios from "axios";
 import middy from "@middy/core";
 // middleware to ensure that the user is part of the given company i.e. permissions
 export const hydrateContext = (): middy.MiddlewareObj<
   APIGatewayProxyEvent,
   APIGatewayProxyResult

leegilmorecode / validate-company-access.ts

Created July 21, 2022 14:57

Middy middleware which is utilised by our Lambda functions

	import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";

	import { UserContext } from "../../../types";
	import middy from "@middy/core";

	// middleware to ensure that the user is part of the given company i.e. permissions
	// when getting their order for a specific company, as well as checking their role
	export const validateCompanyAccessMiddleware = (
	role: string
	): middy.MiddlewareObj<APIGatewayProxyEvent, APIGatewayProxyResult> => {

leegilmorecode / Internal.ts

Created July 21, 2022 14:49

Example of a Lambda Layer in the CDK

	// create our lambda layer for our middleware
	const validationLayer: lambda.LayerVersion = new lambda.LayerVersion(
	this,
	"ValidationLayer",
	{
	compatibleRuntimes: [
	lambda.Runtime.NODEJS_12_X,
	lambda.Runtime.NODEJS_14_X,
	],
	code: lambda.Code.fromAsset("../layers/validation"),

leegilmorecode / external.ts

Created July 21, 2022 14:45

Example of a Cognito Authorizer being added to an endpoint on API Gateway

	// add the cognito authorizer to our api which validates our tokens using cognito
	const cognitoAuthorizer: apigw.CfnAuthorizer = new apigw.CfnAuthorizer(
	this,
	"APIGatewayAuthorizer",
	{
	name: "sushi-orders-authorizer",
	identitySource: "method.request.header.Authorization",
	providerArns: [userPool.userPoolArn],
	restApiId: ordersAPI.restApiId,
	type: apigw.AuthorizationType.COGNITO,

leegilmorecode / internal-stack.ts

Created July 21, 2022 06:50

Example of adding a pre token generation lambda to a Cognito userpool

	// create the cognito user pool for auth
	const authUserPool: cognito.UserPool = new cognito.UserPool(
	this,
	"SushiAuthUserPool",
	{
	userPoolName: "SushiUserAuthUserPool",
	removalPolicy: RemovalPolicy.DESTROY,
	lambdaTriggers: {
	// https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-lambda-pre-token-generation.html
	preTokenGeneration,

leegilmorecode / pre-generation.ts

Created July 21, 2022 06:48

Example of a pre token generation lambda with Amazon Cognito

	import {
	PreTokenGenerationTriggerEvent,
	PreTokenGenerationTriggerHandler,
	} from "aws-lambda";

	import axios from "axios";

	// get the users permissions from a separate service using their token sub
	async function getUserPermissions(userId: string) {
	const { data: userPermissions } = await axios.request({

leegilmorecode / regexes.ts

Created June 29, 2022 11:27

Locale regexes

	interface Regexes {
	[key: string]: any;
	}

	import { getLocale } from "../dynamic-imports";

	const localeRegexes: Regexes = {
	global: {
	firstName: "^[a-z A-Z]+$",
	surname: "^[a-z A-Z]+$",

leegilmorecode / create-sale.schema.ts

Created June 29, 2022 11:26

UK specific version of the create sale schema

	import { regexes } from "@shared/regexes";

	export const schema = {
	type: "object",
	required: ["id", "firstName", "surname", "age"],
	maxProperties: 4,
	minProperties: 4,
	properties: {
	id: {
	type: "number",

leegilmorecode / error-messages.ts

Created June 29, 2022 11:22

Example of returning locale specific error messages using placeholders at build time

	interface Errors {
	[key: string]: any;
	}

	import { getLocale } from "../dynamic-imports";

	// each of these could have different languages or messages
	// specific to the locale
	const localeErrorMessages: Errors = {
	global: {