add fallback addresses getter

Author: futurepaul

lightning-invoice/Cargo.toml

@@ -27,6 +27,7 @@ num-traits = { version = "0.2.8", default-features = false }
 bitcoin_hashes = { version = "0.11", default-features = false }
 hashbrown = { version = "0.8", optional = true }
 serde = { version = "1.0.118", optional = true }
+bitcoin = { version = "0.29.0", default-features = false }
 
 [dev-dependencies]
 lightning = { version = "0.0.113", path = "../lightning", default-features = false, features = ["_test_utils"] }

lightning-invoice/src/de.rs

@@ -907,6 +907,36 @@ mod test {
 		}
 	}
 
+	#[test]
+	fn test_fallback_to_address() {
+		use crate::Fallback;
+		use crate::Currency;
+		use crate::utils::address_from_fallback;
+		use bech32::FromBase32;
+		use bitcoin::Address;
+		use core::str::FromStr;
+
+		let cases = vec![
+			(
+				from_bech32("3x9et2e20v6pu37c5d9vax37wxq72un98".as_bytes()),
+				Address::from_str("15WTXVVv4JHN992HjbRxMwmekcppRpzJrK").unwrap()
+			),
+			(
+				from_bech32("j3a24vwu6r8ejrss3axul8rxldph2q7z9".as_bytes()),
+				Address::from_str("3EktnHQD7RiAE6uzMj2ZifT9YgRrkSgzQX").unwrap()
+			),
+			(
+				from_bech32("qw508d6qejxtdg4y5r3zarvary0c5xw7k".as_bytes()),
+				Address::from_str("bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4").unwrap()
+			),
+		];
+
+		for (input, expected) in cases.into_iter() {
+			let address = address_from_fallback(&Fallback::from_base32(&input).unwrap(), Currency::Bitcoin);
+			assert_eq!(address, expected);
+		}
+	}
+
 	#[test]
 	fn test_parse_route() {
 		use lightning::routing::gossip::RoutingFees;

lightning-invoice/src/lib.rs

@@ -45,6 +45,7 @@ extern crate serde;
 use std::time::SystemTime;
 
 use bech32::u5;
+use bitcoin::Address;
 use bitcoin_hashes::Hash;
 use bitcoin_hashes::sha256;
 use lightning::ln::PaymentSecret;
@@ -1258,6 +1259,13 @@ impl Invoice {
 		self.signed_invoice.fallbacks()
 	}
 
+	/// Returns a list of all fallback addresses as `bitcoin::Address`es
+	pub fn fallback_addresses(&self) -> Vec<Address> {
+		self.fallbacks().iter().map(|fallback| {
+			utils::address_from_fallback(fallback, self.currency())
+		}).collect()
+	}
+
 	/// Returns a list of all routes included in the invoice
 	pub fn private_routes(&self) -> Vec<&PrivateRoute> {
 		self.signed_invoice.private_routes()

lightning-invoice/src/utils.rs

@@ -1,9 +1,11 @@
 //! Convenient utilities to create an invoice.
 
-use crate::{CreationError, Currency, Invoice, InvoiceBuilder, SignOrCreationError};
+use crate::{CreationError, Currency, Invoice, InvoiceBuilder, SignOrCreationError, Fallback};
 
 use crate::{prelude::*, Description, InvoiceDescription, Sha256};
 use bech32::ToBase32;
+use bitcoin::util::address::WitnessVersion;
+use bitcoin::{Network, Address, Script, PubkeyHash, ScriptHash};
 use bitcoin_hashes::Hash;
 use lightning::chain;
 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
@@ -16,6 +18,7 @@ use lightning::routing::gossip::RoutingFees;
 use lightning::routing::router::{RouteHint, RouteHintHop, Router};
 use lightning::util::logger::Logger;
 use secp256k1::PublicKey;
+use core::convert::TryFrom;
 use core::ops::Deref;
 use core::time::Duration;
 
@@ -633,6 +636,33 @@ fn filter_channels<L: Deref>(
 		.collect::<Vec<RouteHint>>()
 }
 
+pub(crate) fn address_from_fallback(fallback: &Fallback, currency: Currency) -> Address {
+	let network = match currency {
+		Currency::Bitcoin => Network::Bitcoin,
+		Currency::BitcoinTestnet => Network::Testnet,
+		Currency::Regtest => Network::Regtest,
+		Currency::Simnet => Network::Regtest,
+		Currency::Signet => Network::Signet,
+	};
+
+	let script = match fallback {
+		Fallback::SegWitProgram { version, program } => {
+			let version = WitnessVersion::try_from(*version).unwrap();
+			Script::new_witness_program(version, program.as_slice())
+		}
+		Fallback::PubKeyHash(pkh) => {
+			let pkh = PubkeyHash::from_slice(pkh).unwrap();
+			Script::new_p2pkh(&pkh)
+		}
+		Fallback::ScriptHash(sh) => {
+			let sh = ScriptHash::from_slice(sh).unwrap();
+			Script::new_p2sh(&sh)
+		}
+	};
+
+	Address::from_script(&script, network).unwrap()
+}
+
 #[cfg(test)]
 mod test {
 	use core::time::Duration;