122 lines
3.6 KiB
TypeScript
122 lines
3.6 KiB
TypeScript
import { bytesToHex } from '@noble/hashes/utils'
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import { sha256 } from '@noble/hashes/sha256'
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import { base64 } from '@scure/base'
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import { Event, EventTemplate, verifyEvent } from './pure.ts'
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import { utf8Decoder, utf8Encoder } from './utils.ts'
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import { HTTPAuth } from './kinds.ts'
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const _authorizationScheme = 'Nostr '
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export function hashPayload(payload: any): string {
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const hash = sha256(utf8Encoder.encode(JSON.stringify(payload)))
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return bytesToHex(hash)
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}
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/**
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* Generate token for NIP-98 flow.
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*
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* @example
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* const sign = window.nostr.signEvent
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* await nip98.getToken('https://example.com/login', 'post', (e) => sign(e), true)
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*/
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export async function getToken(
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loginUrl: string,
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httpMethod: string,
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sign: (e: EventTemplate) => Promise<Event> | Event,
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includeAuthorizationScheme: boolean = false,
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payload?: Record<string, any>,
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): Promise<string> {
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const event: EventTemplate = {
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kind: HTTPAuth,
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tags: [
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['u', loginUrl],
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['method', httpMethod],
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],
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created_at: Math.round(new Date().getTime() / 1000),
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content: '',
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}
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if (payload) {
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event.tags.push(['payload', bytesToHex(sha256(utf8Encoder.encode(JSON.stringify(payload))))])
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}
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const signedEvent = await sign(event)
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const authorizationScheme = includeAuthorizationScheme ? _authorizationScheme : ''
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return authorizationScheme + base64.encode(utf8Encoder.encode(JSON.stringify(signedEvent)))
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}
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/**
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* Validate token for NIP-98 flow.
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*
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* @example
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* await nip98.validateToken('Nostr base64token', 'https://example.com/login', 'post')
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*/
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export async function validateToken(token: string, url: string, method: string): Promise<boolean> {
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const event = await unpackEventFromToken(token).catch(error => {
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throw error
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})
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const valid = await validateEvent(event, url, method).catch(error => {
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throw error
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})
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return valid
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}
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export async function unpackEventFromToken(token: string): Promise<Event> {
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if (!token) {
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throw new Error('Missing token')
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}
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token = token.replace(_authorizationScheme, '')
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const eventB64 = utf8Decoder.decode(base64.decode(token))
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if (!eventB64 || eventB64.length === 0 || !eventB64.startsWith('{')) {
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throw new Error('Invalid token')
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}
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const event = JSON.parse(eventB64) as Event
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return event
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}
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export async function validateEvent(event: Event, url: string, method: string, body?: any): Promise<boolean> {
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if (!event) {
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throw new Error('Invalid nostr event')
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}
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if (!verifyEvent(event)) {
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throw new Error('Invalid nostr event, signature invalid')
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}
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if (event.kind !== HTTPAuth) {
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throw new Error('Invalid nostr event, kind invalid')
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}
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if (!event.created_at) {
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throw new Error('Invalid nostr event, created_at invalid')
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}
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// Event must be less than 60 seconds old
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if (Math.round(new Date().getTime() / 1000) - event.created_at > 60) {
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throw new Error('Invalid nostr event, expired')
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}
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const urlTag = event.tags.find(t => t[0] === 'u')
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if (urlTag?.length !== 1 && urlTag?.[1] !== url) {
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throw new Error('Invalid nostr event, url tag invalid')
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}
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const methodTag = event.tags.find(t => t[0] === 'method')
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if (methodTag?.length !== 1 && methodTag?.[1].toLowerCase() !== method.toLowerCase()) {
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throw new Error('Invalid nostr event, method tag invalid')
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}
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if (Boolean(body) && Object.keys(body).length > 0) {
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const payloadTag = event.tags.find(t => t[0] === 'payload')
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const payloadHash = bytesToHex(sha256(utf8Encoder.encode(JSON.stringify(body))))
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if (payloadTag?.[1] !== payloadHash) {
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throw new Error('Invalid payload tag hash, does not match request body hash')
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}
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}
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return true
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}
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