1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Data structures and encoding for refunds.
12 //! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
13 //! directly to the customer. The recipient responds with an `Invoice` to be paid.
15 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
17 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
18 //! [`Offer`]: crate::offers::offer::Offer
21 //! extern crate bitcoin;
22 //! extern crate core;
23 //! extern crate lightning;
25 //! use core::convert::TryFrom;
26 //! use core::time::Duration;
28 //! use bitcoin::network::constants::Network;
29 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
30 //! use lightning::offers::parse::ParseError;
31 //! use lightning::offers::refund::{Refund, RefundBuilder};
32 //! use lightning::util::ser::{Readable, Writeable};
34 //! # use lightning::onion_message::BlindedPath;
35 //! # #[cfg(feature = "std")]
36 //! # use std::time::SystemTime;
38 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
39 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
41 //! # #[cfg(feature = "std")]
42 //! # fn build() -> Result<(), ParseError> {
43 //! let secp_ctx = Secp256k1::new();
44 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
45 //! let pubkey = PublicKey::from(keys);
47 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
48 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
49 //! .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
50 //! .issuer("Foo Bar".to_string())
51 //! .path(create_blinded_path())
52 //! .path(create_another_blinded_path())
53 //! .chain(Network::Bitcoin)
54 //! .payer_note("refund for order #12345".to_string())
57 //! // Encode as a bech32 string for use in a QR code.
58 //! let encoded_refund = refund.to_string();
60 //! // Parse from a bech32 string after scanning from a QR code.
61 //! let refund = encoded_refund.parse::<Refund>()?;
63 //! // Encode refund as raw bytes.
64 //! let mut bytes = Vec::new();
65 //! refund.write(&mut bytes).unwrap();
67 //! // Decode raw bytes into an refund.
68 //! let refund = Refund::try_from(bytes)?;
73 use bitcoin::blockdata::constants::ChainHash;
74 use bitcoin::network::constants::Network;
75 use bitcoin::secp256k1::PublicKey;
76 use core::convert::TryFrom;
77 use core::str::FromStr;
78 use core::time::Duration;
80 use crate::ln::features::InvoiceRequestFeatures;
81 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
82 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
83 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
84 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
85 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
86 use crate::onion_message::BlindedPath;
87 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
88 use crate::util::string::PrintableString;
90 use crate::prelude::*;
92 #[cfg(feature = "std")]
93 use std::time::SystemTime;
95 /// Builds a [`Refund`] for the "offer for money" flow.
97 /// See [module-level documentation] for usage.
99 /// [module-level documentation]: self
100 pub struct RefundBuilder {
101 refund: RefundContents,
105 /// Creates a new builder for a refund using the [`Refund::payer_id`] for signing invoices. Use
106 /// a different pubkey per refund to avoid correlating refunds.
108 /// Additionally, sets the required [`Refund::description`], [`Refund::metadata`], and
109 /// [`Refund::amount_msats`].
111 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
112 ) -> Result<Self, SemanticError> {
113 if amount_msats > MAX_VALUE_MSAT {
114 return Err(SemanticError::InvalidAmount);
117 let refund = RefundContents {
118 payer: PayerContents(metadata), metadata: None, description, absolute_expiry: None,
119 issuer: None, paths: None, chain: None, amount_msats,
120 features: InvoiceRequestFeatures::empty(), payer_id, payer_note: None,
123 Ok(RefundBuilder { refund })
126 /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
127 /// already passed is valid and can be checked for using [`Refund::is_expired`].
129 /// Successive calls to this method will override the previous setting.
130 pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
131 self.refund.absolute_expiry = Some(absolute_expiry);
135 /// Sets the [`Refund::issuer`].
137 /// Successive calls to this method will override the previous setting.
138 pub fn issuer(mut self, issuer: String) -> Self {
139 self.refund.issuer = Some(issuer);
143 /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
144 /// by private channels or if [`Refund::payer_id`] is not a public node id.
146 /// Successive calls to this method will add another blinded path. Caller is responsible for not
147 /// adding duplicate paths.
148 pub fn path(mut self, path: BlindedPath) -> Self {
149 self.refund.paths.get_or_insert_with(Vec::new).push(path);
153 /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
154 /// called, [`Network::Bitcoin`] is assumed.
156 /// Successive calls to this method will override the previous setting.
157 pub fn chain(mut self, network: Network) -> Self {
158 self.refund.chain = Some(ChainHash::using_genesis_block(network));
162 /// Sets the [`Refund::payer_note`].
164 /// Successive calls to this method will override the previous setting.
165 pub fn payer_note(mut self, payer_note: String) -> Self {
166 self.refund.payer_note = Some(payer_note);
170 /// Builds a [`Refund`] after checking for valid semantics.
171 pub fn build(mut self) -> Result<Refund, SemanticError> {
172 if self.refund.chain() == self.refund.implied_chain() {
173 self.refund.chain = None;
176 let mut bytes = Vec::new();
177 self.refund.write(&mut bytes).unwrap();
181 contents: self.refund,
186 /// A `Refund` is a request to send an `Invoice` without a preceding [`Offer`].
188 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
189 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
192 /// [`Offer`]: crate::offers::offer::Offer
193 #[derive(Clone, Debug)]
196 contents: RefundContents,
199 /// The contents of a [`Refund`], which may be shared with an `Invoice`.
200 #[derive(Clone, Debug)]
201 struct RefundContents {
202 payer: PayerContents,
204 metadata: Option<Vec<u8>>,
206 absolute_expiry: Option<Duration>,
207 issuer: Option<String>,
208 paths: Option<Vec<BlindedPath>>,
209 // invoice_request fields
210 chain: Option<ChainHash>,
212 features: InvoiceRequestFeatures,
214 payer_note: Option<String>,
218 /// A complete description of the purpose of the refund. Intended to be displayed to the user
219 /// but with the caveat that it has not been verified in any way.
220 pub fn description(&self) -> PrintableString {
221 PrintableString(&self.contents.description)
224 /// Duration since the Unix epoch when an invoice should no longer be sent.
226 /// If `None`, the refund does not expire.
227 pub fn absolute_expiry(&self) -> Option<Duration> {
228 self.contents.absolute_expiry
231 /// Whether the refund has expired.
232 #[cfg(feature = "std")]
233 pub fn is_expired(&self) -> bool {
234 match self.absolute_expiry() {
235 Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
236 Ok(elapsed) => elapsed > seconds_from_epoch,
243 /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
244 /// displayed to the user but with the caveat that it has not been verified in any way.
245 pub fn issuer(&self) -> Option<PrintableString> {
246 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
249 /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
250 /// privacy by obfuscating its node id.
251 pub fn paths(&self) -> &[BlindedPath] {
252 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
255 /// An unpredictable series of bytes, typically containing information about the derivation of
258 /// [`payer_id`]: Self::payer_id
259 pub fn metadata(&self) -> &[u8] {
260 &self.contents.payer.0
263 /// A chain that the refund is valid for.
264 pub fn chain(&self) -> ChainHash {
265 self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
268 /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
270 /// [`chain`]: Self::chain
271 pub fn amount_msats(&self) -> u64 {
272 self.contents.amount_msats
275 /// Features pertaining to requesting an invoice.
276 pub fn features(&self) -> &InvoiceRequestFeatures {
277 &self.contents.features
280 /// A possibly transient pubkey used to sign the refund.
281 pub fn payer_id(&self) -> PublicKey {
282 self.contents.payer_id
285 /// Payer provided note to include in the invoice.
286 pub fn payer_note(&self) -> Option<PrintableString> {
287 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
291 impl AsRef<[u8]> for Refund {
292 fn as_ref(&self) -> &[u8] {
297 impl RefundContents {
298 fn chain(&self) -> ChainHash {
299 self.chain.unwrap_or_else(|| self.implied_chain())
302 pub fn implied_chain(&self) -> ChainHash {
303 ChainHash::using_genesis_block(Network::Bitcoin)
306 pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
307 let payer = PayerTlvStreamRef {
308 metadata: Some(&self.payer.0),
311 let offer = OfferTlvStreamRef {
313 metadata: self.metadata.as_ref(),
316 description: Some(&self.description),
318 absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
319 paths: self.paths.as_ref(),
320 issuer: self.issuer.as_ref(),
326 if self.features == InvoiceRequestFeatures::empty() { None }
327 else { Some(&self.features) }
330 let invoice_request = InvoiceRequestTlvStreamRef {
331 chain: self.chain.as_ref(),
332 amount: Some(self.amount_msats),
335 payer_id: Some(&self.payer_id),
336 payer_note: self.payer_note.as_ref(),
339 (payer, offer, invoice_request)
343 impl Writeable for Refund {
344 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
345 WithoutLength(&self.bytes).write(writer)
349 impl Writeable for RefundContents {
350 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
351 self.as_tlv_stream().write(writer)
355 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
357 type RefundTlvStreamRef<'a> = (
358 PayerTlvStreamRef<'a>,
359 OfferTlvStreamRef<'a>,
360 InvoiceRequestTlvStreamRef<'a>,
363 impl SeekReadable for RefundTlvStream {
364 fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
365 let payer = SeekReadable::read(r)?;
366 let offer = SeekReadable::read(r)?;
367 let invoice_request = SeekReadable::read(r)?;
369 Ok((payer, offer, invoice_request))
373 impl Bech32Encode for Refund {
374 const BECH32_HRP: &'static str = "lnr";
377 impl FromStr for Refund {
378 type Err = ParseError;
380 fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
381 Refund::from_bech32_str(s)
385 impl TryFrom<Vec<u8>> for Refund {
386 type Error = ParseError;
388 fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
389 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
390 let ParsedMessage { bytes, tlv_stream } = refund;
391 let contents = RefundContents::try_from(tlv_stream)?;
393 Ok(Refund { bytes, contents })
397 impl TryFrom<RefundTlvStream> for RefundContents {
398 type Error = SemanticError;
400 fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
402 PayerTlvStream { metadata: payer_metadata },
404 chains, metadata, currency, amount: offer_amount, description,
405 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
407 InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
410 let payer = match payer_metadata {
411 None => return Err(SemanticError::MissingPayerMetadata),
412 Some(metadata) => PayerContents(metadata),
415 if chains.is_some() {
416 return Err(SemanticError::UnexpectedChain);
419 if currency.is_some() || offer_amount.is_some() {
420 return Err(SemanticError::UnexpectedAmount);
423 let description = match description {
424 None => return Err(SemanticError::MissingDescription),
425 Some(description) => description,
428 if offer_features.is_some() {
429 return Err(SemanticError::UnexpectedFeatures);
432 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
434 if quantity_max.is_some() {
435 return Err(SemanticError::UnexpectedQuantity);
438 if node_id.is_some() {
439 return Err(SemanticError::UnexpectedSigningPubkey);
442 let amount_msats = match amount {
443 None => return Err(SemanticError::MissingAmount),
444 Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
445 return Err(SemanticError::InvalidAmount);
447 Some(amount_msats) => amount_msats,
450 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
452 // TODO: Check why this isn't in the spec.
453 if quantity.is_some() {
454 return Err(SemanticError::UnexpectedQuantity);
457 let payer_id = match payer_id {
458 None => return Err(SemanticError::MissingPayerId),
459 Some(payer_id) => payer_id,
462 // TODO: Should metadata be included?
464 payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
465 features, payer_id, payer_note,
470 impl core::fmt::Display for Refund {
471 fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
472 self.fmt_bech32_str(f)