101 lines
2.9 KiB
TypeScript
101 lines
2.9 KiB
TypeScript
import { base64 } from '@scure/base'
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import { Event, EventTemplate, Kind, getBlankEvent, verifySignature } from './event'
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import { utf8Decoder, utf8Encoder } from './utils'
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const _authorizationScheme = 'Nostr '
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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: <K extends number = number>(e: EventTemplate<K>) => Promise<Event<K>> | Event<K>,
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includeAuthorizationScheme: boolean = false,
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): Promise<string> {
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if (!loginUrl || !httpMethod) throw new Error('Missing loginUrl or httpMethod')
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const event = getBlankEvent(Kind.HttpAuth)
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event.tags = [
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['u', loginUrl],
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['method', httpMethod],
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]
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event.created_at = Math.round(new Date().getTime() / 1000)
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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): 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 (!verifySignature(event)) {
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throw new Error('Invalid nostr event, signature invalid')
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}
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if (event.kind !== 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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return true
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}
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