RawBolt11Invoice to/from ascii utilities

for remote signing of invoices

lightning-invoice/src/lib.rs

@@ -30,7 +30,7 @@ extern crate serde;
 #[cfg(feature = "std")]
 use std::time::SystemTime;
 
-use bech32::primitives::decode::CheckedHrpstringError;
+use bech32::primitives::decode::{CheckedHrpstringError, UncheckedHrpstring};
 use bech32::Fe32;
 use bitcoin::hashes::{sha256, Hash};
 use bitcoin::{Address, Network, PubkeyHash, ScriptHash, WitnessProgram, WitnessVersion};
@@ -80,6 +80,10 @@ use crate::prelude::*;
 pub use crate::de::FromBase32;
 #[cfg(fuzzing)]
 pub use crate::ser::Base32Iterable;
+#[cfg(not(fuzzing))]
+use crate::de::FromBase32;
+#[cfg(not(fuzzing))]
+use crate::ser::Base32Iterable;
 
 /// Errors that indicate what is wrong with the invoice. They have some granularity for debug
 /// reasons, but should generally result in an "invalid BOLT11 invoice" message for the user.
@@ -1189,6 +1193,31 @@ impl RawBolt11Invoice {
 	pub fn currency(&self) -> Currency {
 		self.hrp.currency.clone()
 	}
+
+	/// Convert to ascii bytes with HRP prefix and base32 encoded data part.
+	/// Can be used to transmit unsigned invoices for remote signing.
+	pub fn to_ascii(&self) -> Vec<u8> {
+		self.hrp.to_string().into_bytes().into_iter()
+			.chain(self.data.fe_iter().map(|e| e.to_char() as u8)).collect()
+	}
+
+	/// Convert from ascii bytes with HRP prefix and base32 encoded data part.
+	/// Can be used to receive unsigned invoices for remote signing.
+	pub fn from_ascii(s: &str) -> Result<Self, Bolt11ParseError> {
+		let parsed = UncheckedHrpstring::new(s)
+			.map_err(|_| Bolt11ParseError::MalformedHRP)?;
+		let hrp = parsed.hrp();
+		let raw_hrp: RawHrp = hrp.to_string().to_lowercase().parse()?;
+
+		let data = parsed.data_part_ascii().iter().map(|c| Fe32::from_char(*c as char)).collect::<Result<Vec<_>, _>>()
+			.map_err(|_| Bolt11ParseError::MalformedHRP)?;
+		let data_part = RawDataPart::from_base32(&data)?;
+
+		Ok(Self {
+			hrp: raw_hrp,
+			data: data_part,
+		})
+	}
 }
 
 impl PositiveTimestamp {