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 fn as_tlv_stream(&self) -> RefundTlvStreamRef {
292 self.contents.as_tlv_stream()
296 impl AsRef<[u8]> for Refund {
297 fn as_ref(&self) -> &[u8] {
302 impl RefundContents {
303 fn chain(&self) -> ChainHash {
304 self.chain.unwrap_or_else(|| self.implied_chain())
307 pub fn implied_chain(&self) -> ChainHash {
308 ChainHash::using_genesis_block(Network::Bitcoin)
311 pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
312 let payer = PayerTlvStreamRef {
313 metadata: Some(&self.payer.0),
316 let offer = OfferTlvStreamRef {
318 metadata: self.metadata.as_ref(),
321 description: Some(&self.description),
323 absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
324 paths: self.paths.as_ref(),
325 issuer: self.issuer.as_ref(),
331 if self.features == InvoiceRequestFeatures::empty() { None }
332 else { Some(&self.features) }
335 let invoice_request = InvoiceRequestTlvStreamRef {
336 chain: self.chain.as_ref(),
337 amount: Some(self.amount_msats),
340 payer_id: Some(&self.payer_id),
341 payer_note: self.payer_note.as_ref(),
344 (payer, offer, invoice_request)
348 impl Writeable for Refund {
349 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
350 WithoutLength(&self.bytes).write(writer)
354 impl Writeable for RefundContents {
355 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
356 self.as_tlv_stream().write(writer)
360 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
362 type RefundTlvStreamRef<'a> = (
363 PayerTlvStreamRef<'a>,
364 OfferTlvStreamRef<'a>,
365 InvoiceRequestTlvStreamRef<'a>,
368 impl SeekReadable for RefundTlvStream {
369 fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
370 let payer = SeekReadable::read(r)?;
371 let offer = SeekReadable::read(r)?;
372 let invoice_request = SeekReadable::read(r)?;
374 Ok((payer, offer, invoice_request))
378 impl Bech32Encode for Refund {
379 const BECH32_HRP: &'static str = "lnr";
382 impl FromStr for Refund {
383 type Err = ParseError;
385 fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
386 Refund::from_bech32_str(s)
390 impl TryFrom<Vec<u8>> for Refund {
391 type Error = ParseError;
393 fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
394 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
395 let ParsedMessage { bytes, tlv_stream } = refund;
396 let contents = RefundContents::try_from(tlv_stream)?;
398 Ok(Refund { bytes, contents })
402 impl TryFrom<RefundTlvStream> for RefundContents {
403 type Error = SemanticError;
405 fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
407 PayerTlvStream { metadata: payer_metadata },
409 chains, metadata, currency, amount: offer_amount, description,
410 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
412 InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
415 let payer = match payer_metadata {
416 None => return Err(SemanticError::MissingPayerMetadata),
417 Some(metadata) => PayerContents(metadata),
420 if chains.is_some() {
421 return Err(SemanticError::UnexpectedChain);
424 if currency.is_some() || offer_amount.is_some() {
425 return Err(SemanticError::UnexpectedAmount);
428 let description = match description {
429 None => return Err(SemanticError::MissingDescription),
430 Some(description) => description,
433 if offer_features.is_some() {
434 return Err(SemanticError::UnexpectedFeatures);
437 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
439 if quantity_max.is_some() {
440 return Err(SemanticError::UnexpectedQuantity);
443 if node_id.is_some() {
444 return Err(SemanticError::UnexpectedSigningPubkey);
447 let amount_msats = match amount {
448 None => return Err(SemanticError::MissingAmount),
449 Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
450 return Err(SemanticError::InvalidAmount);
452 Some(amount_msats) => amount_msats,
455 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
457 // TODO: Check why this isn't in the spec.
458 if quantity.is_some() {
459 return Err(SemanticError::UnexpectedQuantity);
462 let payer_id = match payer_id {
463 None => return Err(SemanticError::MissingPayerId),
464 Some(payer_id) => payer_id,
467 // TODO: Should metadata be included?
469 payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
470 features, payer_id, payer_note,
475 impl core::fmt::Display for Refund {
476 fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
477 self.fmt_bech32_str(f)
483 use super::{Refund, RefundBuilder};
485 use bitcoin::blockdata::constants::ChainHash;
486 use bitcoin::network::constants::Network;
487 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
488 use core::convert::TryFrom;
489 use core::time::Duration;
490 use crate::ln::features::InvoiceRequestFeatures;
491 use crate::ln::msgs::MAX_VALUE_MSAT;
492 use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
493 use crate::offers::offer::OfferTlvStreamRef;
494 use crate::offers::parse::SemanticError;
495 use crate::offers::payer::PayerTlvStreamRef;
496 use crate::onion_message::{BlindedHop, BlindedPath};
497 use crate::util::ser::Writeable;
498 use crate::util::string::PrintableString;
500 fn payer_pubkey() -> PublicKey {
501 let secp_ctx = Secp256k1::new();
502 KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()).public_key()
505 fn pubkey(byte: u8) -> PublicKey {
506 let secp_ctx = Secp256k1::new();
507 PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
510 fn privkey(byte: u8) -> SecretKey {
511 SecretKey::from_slice(&[byte; 32]).unwrap()
515 fn builds_refund_with_defaults() {
516 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
519 let mut buffer = Vec::new();
520 refund.write(&mut buffer).unwrap();
522 assert_eq!(refund.bytes, buffer.as_slice());
523 assert_eq!(refund.metadata(), &[1; 32]);
524 assert_eq!(refund.description(), PrintableString("foo"));
525 assert_eq!(refund.absolute_expiry(), None);
526 #[cfg(feature = "std")]
527 assert!(!refund.is_expired());
528 assert_eq!(refund.paths(), &[]);
529 assert_eq!(refund.issuer(), None);
530 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
531 assert_eq!(refund.amount_msats(), 1000);
532 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
533 assert_eq!(refund.payer_id(), payer_pubkey());
534 assert_eq!(refund.payer_note(), None);
537 refund.as_tlv_stream(),
539 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
545 description: Some(&String::from("foo")),
547 absolute_expiry: None,
553 InvoiceRequestTlvStreamRef {
558 payer_id: Some(&payer_pubkey()),
564 if let Err(e) = Refund::try_from(buffer) {
565 panic!("error parsing refund: {:?}", e);
570 fn fails_building_refund_with_invalid_amount() {
571 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
572 Ok(_) => panic!("expected error"),
573 Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
578 fn builds_refund_with_absolute_expiry() {
579 let future_expiry = Duration::from_secs(u64::max_value());
580 let past_expiry = Duration::from_secs(0);
582 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
583 .absolute_expiry(future_expiry)
586 let (_, tlv_stream, _) = refund.as_tlv_stream();
587 #[cfg(feature = "std")]
588 assert!(!refund.is_expired());
589 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
590 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
592 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
593 .absolute_expiry(future_expiry)
594 .absolute_expiry(past_expiry)
597 let (_, tlv_stream, _) = refund.as_tlv_stream();
598 #[cfg(feature = "std")]
599 assert!(refund.is_expired());
600 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
601 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
605 fn builds_refund_with_paths() {
608 introduction_node_id: pubkey(40),
609 blinding_point: pubkey(41),
611 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
612 BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
616 introduction_node_id: pubkey(40),
617 blinding_point: pubkey(41),
619 BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
620 BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
625 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
626 .path(paths[0].clone())
627 .path(paths[1].clone())
630 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
631 assert_eq!(refund.paths(), paths.as_slice());
632 assert_eq!(refund.payer_id(), pubkey(42));
633 assert_ne!(pubkey(42), pubkey(44));
634 assert_eq!(offer_tlv_stream.paths, Some(&paths));
635 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
639 fn builds_refund_with_issuer() {
640 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
641 .issuer("bar".into())
644 let (_, tlv_stream, _) = refund.as_tlv_stream();
645 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
646 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
648 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
649 .issuer("bar".into())
650 .issuer("baz".into())
653 let (_, tlv_stream, _) = refund.as_tlv_stream();
654 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
655 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
659 fn builds_refund_with_chain() {
660 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
661 let testnet = ChainHash::using_genesis_block(Network::Testnet);
663 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
664 .chain(Network::Bitcoin)
666 let (_, _, tlv_stream) = refund.as_tlv_stream();
667 assert_eq!(refund.chain(), mainnet);
668 assert_eq!(tlv_stream.chain, None);
670 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
671 .chain(Network::Testnet)
673 let (_, _, tlv_stream) = refund.as_tlv_stream();
674 assert_eq!(refund.chain(), testnet);
675 assert_eq!(tlv_stream.chain, Some(&testnet));
677 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
678 .chain(Network::Regtest)
679 .chain(Network::Testnet)
681 let (_, _, tlv_stream) = refund.as_tlv_stream();
682 assert_eq!(refund.chain(), testnet);
683 assert_eq!(tlv_stream.chain, Some(&testnet));
687 fn builds_refund_with_payer_note() {
688 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
689 .payer_note("bar".into())
691 let (_, _, tlv_stream) = refund.as_tlv_stream();
692 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
693 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
695 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
696 .payer_note("bar".into())
697 .payer_note("baz".into())
699 let (_, _, tlv_stream) = refund.as_tlv_stream();
700 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
701 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));