Files
sattle/src/lnurlcash/receive.ts
T

88 lines
2.8 KiB
TypeScript

import {
resolveNoteInput,
noteK1,
noteDeclaredAmount,
serverOf,
fetchNoteInfo,
rotateNote,
withNewK1,
NoteSpentError,
NoteUnknownError,
PendingNoteError
} from 'lnurlcash-kit'
import type {Bearer, NewBearer} from './types'
// shared by Scan and Paste: resolve whatever came in to a note URL, ask the
// issuing service what it is worth (an informational GET - per spec this
// always puts k1 on the wire, so receive.ts's caller should rotate right
// after, see secureReceivedNote). Returns the note even when the info fetch
// fails - a bearer is better stored unverified than dropped.
export const receiveNote = async (
input: string,
existing: Bearer[]
): Promise<NewBearer> => {
const url = resolveNoteInput(input)
if (!url) {
throw new Error('Not an LNURLcash bearer note (needs a k1).')
}
const k1 = noteK1(url)
if (
existing.some(
b => noteK1(b.url) === k1 && serverOf(b.url) === serverOf(url)
)
) {
throw new Error('This note is already in your wallet.')
}
try {
const info = await fetchNoteInfo(url)
return {
url,
callback: info.callback,
amount: info.maxWithdrawable,
verified: true,
mintPubkey: info.mintPubkey
}
} catch (err) {
// the service positively told us this k1 is dead, unknown, or locked
// mid-melt (pending) - all definitive states the caller must surface
// distinctly, so don't paper over them with an unverified fallback the
// way an unreachable/unknown-shaped error below does. The caller never
// stores the note in these cases.
if (
err instanceof NoteSpentError ||
err instanceof NoteUnknownError ||
err instanceof PendingNoteError
) {
throw err
}
// service unreachable (or some other non-definitive failure) - fall
// back to the sender's own (unverified) declared amount so the note
// isn't shown as worth nothing
return {
url,
callback: '',
amount: noteDeclaredAmount(url) ?? 0,
verified: false
}
}
}
// After receiving a note, rotate it: the previous holder (and anything that
// logged the URL in transit, since the informational GET above already put
// k1 on the wire) still knows the old secret - a rotate burns it and mints
// a fresh one only this wallet knows. Returns the updated note URL. Throws
// when the service refuses (e.g. a plain LUD-03 withdraw link that doesn't
// speak lnurlcash) - the caller should warn, not fail the receive.
export const secureReceivedNote = async (note: {
url: string
callback: string
amount: number
}): Promise<string> => {
const k1 = noteK1(note.url)
if (!k1 || !note.callback) {
throw new Error('Note has no callback to rotate against yet.')
}
const result = await rotateNote(note.callback, k1)
return withNewK1(note.url, result.k1, note.amount, result.signature)
}