118 lines
3.4 KiB
TypeScript
118 lines
3.4 KiB
TypeScript
import { Event, validateEvent, verifySignature } from 'nostr-tools'
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/**
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* Service for verifying zap receipts and their signatures
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*/
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export class ZapVerificationService {
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/**
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* Verify a zap receipt signature
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*/
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verifyZapReceiptSignature(event: Event): boolean {
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try {
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return validateEvent(event) && verifySignature(event)
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} catch (error) {
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console.error('Error verifying zap receipt signature:', error)
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return false
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}
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}
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/**
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* Check if a zap receipt is valid for a specific article and user
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*/
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verifyZapReceiptForArticle(
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zapReceipt: Event,
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articleId: string,
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articlePubkey: string,
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_userPubkey: string,
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expectedAmount: number
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): boolean {
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if (!this.verifyZapReceiptSignature(zapReceipt)) {
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console.warn('Zap receipt signature verification failed')
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return false
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}
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return (
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this.isRecipientValid(zapReceipt, articlePubkey) &&
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this.isArticleReferenced(zapReceipt, articleId) &&
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this.isAmountValid(zapReceipt, expectedAmount) &&
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this.isZapKind(zapReceipt)
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)
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}
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/**
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* Extract payment information from a zap receipt
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*/
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extractPaymentInfo(zapReceipt: Event): {
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amount: number // in satoshis
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recipient: string
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articleId: string | null
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payer: string
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} | null {
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try {
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const amountTag = zapReceipt.tags.find((tag) => tag[0] === 'amount')
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const recipientTag = zapReceipt.tags.find((tag) => tag[0] === 'p')
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const eventTag = zapReceipt.tags.find((tag) => tag[0] === 'e')
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if (!amountTag || !recipientTag) {
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return null
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}
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const amountInMillisats = parseInt(amountTag[1] ?? '0')
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const amountInSats = Math.floor(amountInMillisats / 1000)
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return {
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amount: amountInSats,
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recipient: recipientTag?.[1] ?? '',
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articleId: eventTag?.[1] ?? null,
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payer: zapReceipt.pubkey,
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}
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} catch (error) {
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console.error('Error extracting payment info:', error)
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return null
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}
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}
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private isRecipientValid(zapReceipt: Event, articlePubkey: string): boolean {
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const recipient = zapReceipt.tags.find((tag) => tag[0] === 'p')?.[1]
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if (recipient !== articlePubkey) {
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console.warn('Zap receipt recipient does not match article author')
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return false
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}
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return true
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}
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private isArticleReferenced(zapReceipt: Event, articleId: string): boolean {
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const eventIdTag = zapReceipt.tags.find((tag) => tag[0] === 'e')?.[1]
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if (eventIdTag !== articleId) {
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console.warn('Zap receipt does not reference the correct article')
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return false
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}
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return true
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}
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private isAmountValid(zapReceipt: Event, expectedAmount: number): boolean {
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const amountTag = zapReceipt.tags.find((tag) => tag[0] === 'amount')?.[1]
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if (!amountTag) {
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console.warn('Zap receipt does not contain amount tag')
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return false
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}
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const amountInMillisats = parseInt(amountTag ?? '0')
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const expectedAmountInMillisats = expectedAmount * 1000
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if (amountInMillisats < expectedAmountInMillisats) {
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console.warn(`Zap amount ${amountInMillisats} is less than expected ${expectedAmountInMillisats}`)
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return false
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}
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return true
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}
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private isZapKind(zapReceipt: Event): boolean {
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if (zapReceipt.kind !== 9735) {
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console.warn('Event is not a zap receipt (kind 9735)')
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return false
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}
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return true
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}
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}
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export const zapVerificationService = new ZapVerificationService()
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