adding hardware signers

Author: ulrichard

Cargo.lock

@@ -71,6 +71,9 @@ esplora-reqwest = ["esplora", "bdk/use-esplora-reqwest", "bdk/reqwest-default-tl
 # Use this to consensus verify transactions at sync time
 verify = ["bdk/verify"]
 
+# Use hardware wallets to sign transactions
+hardware-signer = ["bdk/hardware-signer"]
+
 # Extra utility tools
 # Compile policies
 compiler = ["bdk/compiler"]
@@ -93,4 +96,4 @@ regtest-electrum = ["regtest-node", "electrum", "electrsd/electrs_0_8_10"]
 # This feature is used to run `cargo check` in our CI targeting wasm. It's not recommended
 # for libraries to explicitly include the "getrandom/js" feature, so we only do it when
 # necessary for running our CI. See: https://docs.rs/getrandom/0.2.8/getrandom/#webassembly-support
-dev-getrandom-wasm = ["getrandom/js"]
+dev-getrandom-wasm = ["getrandom/js"]

Cargo.toml

@@ -565,6 +565,9 @@ pub enum KeySubCommand {
         #[clap(name = "PATH", short = 'p', long = "path")]
         path: DerivationPath,
     },
+    #[cfg(feature = "hardware-signer")]
+    /// List the public descriptors of the available hardware wallets
+    Hardware {},
 }
 
 /// Subcommands available in REPL mode.

src/commands.rs

@@ -50,13 +50,20 @@ use bdk::descriptor::Segwitv0;
 use bdk::descriptor::{Descriptor, Legacy, Miniscript};
 #[cfg(all(feature = "reserves", feature = "electrum"))]
 use bdk::electrum_client::{Client, ElectrumApi};
+#[cfg(feature = "hardware-signer")]
+use bdk::hwi::{
+    interface::HWIClient,
+    types::{HWIChain, HWIDescriptor},
+};
 use bdk::keys::bip39::{Language, Mnemonic, WordCount};
 use bdk::keys::DescriptorKey::Secret;
 use bdk::keys::KeyError::{InvalidNetwork, Message};
 use bdk::keys::{DerivableKey, DescriptorKey, ExtendedKey, GeneratableKey, GeneratedKey};
 use bdk::miniscript::miniscript;
 #[cfg(feature = "compiler")]
 use bdk::miniscript::policy::Concrete;
+#[cfg(feature = "hardware-signer")]
+use bdk::wallet::signer::SignerError;
 use bdk::SignOptions;
 #[cfg(all(feature = "reserves", feature = "electrum"))]
 use bdk::{bitcoin::Address, blockchain::Capability};
@@ -487,6 +494,26 @@ pub(crate) fn handle_key_subcommand(
                 Err(Error::Key(Message("Invalid key variant".to_string())))
             }
         }
+        #[cfg(feature = "hardware-signer")]
+        KeySubCommand::Hardware {} => {
+            let chain = match network {
+                Network::Bitcoin => HWIChain::Main,
+                Network::Testnet => HWIChain::Test,
+                Network::Regtest => HWIChain::Regtest,
+                Network::Signet => HWIChain::Signet,
+            };
+            let devices = HWIClient::enumerate().map_err(|e| SignerError::from(e))?;
+            let descriptors = devices.iter().map(|device_| {
+                let device = device_.clone()
+                    .map_err(|e| SignerError::from(e))?;
+                let client = HWIClient::get_client(&device, true, chain.clone())
+                    .map_err(|e| SignerError::from(e))?;
+                let descriptors: HWIDescriptor<String> = client.get_descriptors(None)
+                    .map_err(|e| SignerError::from(e))?;
+                Ok(json!({"device": device.model, "receiving": descriptors.receive[0].to_string(), "change": descriptors.internal[0]})) 
+            }).collect::<Result<Vec<_>, Error>>()?;
+            Ok(json!(descriptors))
+        }
     }
 }
 

src/handlers.rs

@@ -43,8 +43,18 @@ use bdk::database::any::SledDbConfiguration;
 #[cfg(feature = "sqlite-db")]
 use bdk::database::any::SqliteDbConfiguration;
 use bdk::database::{AnyDatabase, AnyDatabaseConfig, BatchDatabase, ConfigurableDatabase};
+#[cfg(feature = "hardware-signer")]
+use bdk::hwi::{interface::HWIClient, types::HWIChain};
+#[cfg(feature = "hardware-signer")]
+use bdk::wallet::hardwaresigner::HWISigner;
+#[cfg(feature = "hardware-signer")]
+use bdk::wallet::signer::{SignerError, SignerOrdering};
 use bdk::wallet::wallet_name_from_descriptor;
+#[cfg(feature = "hardware-signer")]
+use bdk::KeychainKind;
 use bdk::{Error, Wallet};
+#[cfg(feature = "hardware-signer")]
+use std::sync::Arc;
 
 /// Create a randomized wallet name from the descriptor checksum.
 /// If wallet options already includes a name, use that instead.
@@ -497,5 +507,41 @@ where
     let descriptor = wallet_opts.descriptor.as_str();
     let change_descriptor = wallet_opts.change_descriptor.as_deref();
     let wallet = Wallet::new(descriptor, change_descriptor, network, database)?;
+
+    #[cfg(feature = "hardware-signer")]
+    let wallet = add_hardware_signers(wallet, network)?;
+
+    Ok(wallet)
+}
+
+/// Add hardware wallets as signers to the wallet
+#[cfg(feature = "hardware-signer")]
+fn add_hardware_signers<D>(wallet: Wallet<D>, network: Network) -> Result<Wallet<D>, Error>
+where
+    D: BatchDatabase,
+{
+    let mut wallet = wallet;
+    let chain = match network {
+        Network::Bitcoin => HWIChain::Main,
+        Network::Testnet => HWIChain::Test,
+        Network::Regtest => HWIChain::Regtest,
+        Network::Signet => HWIChain::Signet,
+    };
+    let devices = HWIClient::enumerate().map_err(|e| SignerError::from(e))?;
+    for device in devices {
+        let device = device.map_err(|e| SignerError::from(e))?;
+        // Creating a custom signer from the device
+        let custom_signer =
+            HWISigner::from_device(&device, chain.clone()).map_err(|e| SignerError::from(e))?;
+
+        // Adding the hardware signer to the BDK wallet
+        wallet.add_signer(
+            KeychainKind::External,
+            SignerOrdering(200),
+            Arc::new(custom_signer),
+        );
+        println!("Added {} as a signer to the wallet.", device.model);
+    }
+
     Ok(wallet)
 }