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SheIITear/cookieHandler.ts

Last active November 19, 2024 13:59
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Just a piece of code you can use to handle user authentication (cookies and validating them) in memory. This is not made for anything more than testing / PoC. (ps written for a school project)
Raw
cookieHandler.ts
import { randomBytes, createHmac } from 'crypto'
interface UserData {
cookie: string
ttl: number
salt: string
}
export class Auth {
#storage: Map<string, UserData>
#secret: string
#ttl: number
constructor(secret: string, ttl: number) {
console.log(`Setting up auth storage with ttl of ${ttl}`)
this.#storage = new Map<string, UserData>()
this.#secret = secret
this.#ttl = ttl
}
private getStorage = (userId: string) => this.#storage.get(userId)
private delField = (userId: string) => this.#storage.delete(userId)
private updateStorage = (userId: string, data: UserData) => this.#storage.set(userId, data)
private userIdFromCookie = (cookie: string): string => cookie.split('.')[0]
private genCookie = (userId: string, salt: string) => {
const cookie = this.getIdentifier(userId)
const signature = this.generateSignature(cookie, salt)
return `${cookie}.${signature}`
}
private getIdentifier = (userId: string): string => {
const keyBuffer = Buffer.from(userId)
const result = keyBuffer.toString('base64')
return result
}
private generateSignature = (data: string, salt: string): string => {
const hmac = createHmac('sha256', this.#secret)
hmac.update(data + salt)
return hmac.digest('base64')
}
private verifySignature = (cookie: string, salt: string): boolean => {
const [data, signature] = cookie.split('.')
const expectedSignature = this.generateSignature(data, salt)
return signature === expectedSignature;
}
private cleaner = (userId: string) => {
setTimeout(() => {
this.delField(userId)
}, this.#ttl)
}
isUserLoggedin = (cookie: string): boolean => {
const userId = this.userIdFromCookie(cookie)
const userData = this.getStorage(userId)
if (!userData) {
return false
}
const { ttl, salt } = userData
if (ttl < Date.now()) {
this.delField(userId)
return false;
}
if (!this.verifySignature(cookie, salt)) {
return false;
}
return true;
}
setLoggedIn = (userId: string): string => {
const salt = randomBytes(16).toString('hex')
const cookie = this.genCookie(userId, salt)
const encodedId = Buffer.from(userId).toString('base64')
const userData: UserData = {
cookie: cookie,
ttl: Date.now() + this.#ttl,
salt: salt
}
this.updateStorage(encodedId, userData)
this.cleaner(encodedId)
return cookie
}
setLoggedOut = (cookie: string) => {
this.delField(this.userIdFromCookie(cookie))
return
}
}
@SheIITear
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Usage:

const auth = new Auth('you will never guess this', 1*1000*60) // setup 

const cookie = auth.setLoggedIn(username) // log user in

const loggedIn = auth.isUserLoggedin(cookie) // check if cookie is valid

auth.setLoggedOut(cookie) // log out a cookie

It should be relatively easy to add stuff like user privileges etc.

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