@byu-oit-sdk/session-express

Requirements:

• Node.js 18+
  • or Node.js 10+ with fetch and crypto polyfills
• npm v9+
• Express v4

Install

npm i @byu-oit-sdk/session-express
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Introduction

Use this module to facilitate session authentication, used primarily in conjunction with the @byu-oit-sdk/express package.

Options

The only parameter passed into SessionMiddleware (see the example below) is an object where the following options can be set:

None of the options are required to be overridden for testing, but store must be overridden for production use.

Usage

Register the return value of SessionMiddleware as an express middleware:

import env from 'env-var'
import { LoggerMiddleware } from '@byu-oit/express-logger'
import { AuthorizationCodeFlow } from '@byu-oit-sdk/express'
import express, { type Response } from 'express'
import { SessionMiddleware } from '@byu-oit-sdk/session-express'
import type { Request } from 'express-serve-static-core'
import { createDecoder } from 'fast-jwt'
import { DynamoSessionStore } from '@byu-oit-sdk/session-dynamo'
import { DynamoDBClient } from '@aws-sdk/client-dynamodb'

declare module '@byu-oit-sdk/express' {
    interface UserInfo {
        /**
         * Declare your user info object properties here
         */
    }
}

export const app = express()

const secret = env.get('BYU_OIT_SIGNING_SECRET').required().asString()
const isProduction = env.get('NODE_ENV').default('development').asEnum(['production', 'development']) === 'production'

let store
if (isProduction) {
  const client = new DynamoDBClient({
    region: env.get('AWS_REGION').required().asString(),
    endpoint: 'http://localhost:8000'
  })
  store = new DynamoSessionStore({ client, tableName: 'sessions' })
}

/**
 *  Must register the @byu-oit-sdk/session-express middleware. You must pass in a session storage option for production environments.
 *  Using the default in-memory storage is highly discouraged because it will cause memory leaks.
 */
const sessionMiddleware = await SessionMiddleware({ store })
app.use(sessionMiddleware)

/**
 * Attach the logger to the express instance
 */
app.use(LoggerMiddleware())

/* Initialize jwt decoder for user info callback */
const decode = createDecoder()

/**
 * Attach the auth middleware we're using
 */
AuthorizationCodeFlow(app, {
    /**
     * A user info callback function can be supplied to implement a custom way to return the user info data.
     * the default behavior is to decode the access token returned from the oauth provider token endpoint.
     * The context of the `userInfoCallback` function is bound to the ExpressAuthorizationCodeProvider instance.
     */
    userInfoCallback (token) {
        if (typeof token.additional.id_token !== 'string') {
            /** At BYU OIT the `id_token` property exists in the token response body. We can access it on the `additional` property on the token object. */
            throw Error('Missing or mal-formatted ID token in response from token endpoint. Did you set the right scopes?')
        }
        /** Decode the `id_token` property, which should return the user info object. */
        return decode(token.additional.id_token)
    }
})

/**
 * To require authentication for a route, just specify the authenticate function on the request object in the onRequest hook.
 */
app.get('/auth/user', (req: Request, res: Response) => {
    res.contentType('application/json').send(req.session.user)
})

app.use((err, req, res, _next) => {
    console.error(err.stack)
    res.status(500).send('Something broke!')
})
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