Add psbt_signer.rs example

Author: notmandatory

examples/psbt_signer.rs

@@ -0,0 +1,102 @@
+// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+#[cfg(feature = "electrum")]
+use bdk::blockchain::{Blockchain, ElectrumBlockchain};
+use bdk::database::MemoryDatabase;
+use bdk::wallet::AddressIndex;
+#[cfg(feature = "electrum")]
+use bdk::SyncOptions;
+use bdk::{FeeRate, SignOptions, Wallet};
+use bitcoin::Network;
+#[cfg(feature = "electrum")]
+use electrum_client::Client;
+use std::error::Error;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    // created test keys with `bdk-cli key generate` and `bdk-cli key derive` commands
+    let signing_external_descriptor = "wpkh([e9824965/84'/1'/0']tprv8fvem7qWxY3SGCQczQpRpqTKg455wf1zgixn6MZ4ze8gRfHjov5gXBQTadNfDgqs9ERbZZ3Bi1PNYrCCusFLucT39K525MWLpeURjHwUsfX/0/*)";
+    let signing_internal_descriptor = "wpkh([e9824965/84'/1'/0']tprv8fvem7qWxY3SGCQczQpRpqTKg455wf1zgixn6MZ4ze8gRfHjov5gXBQTadNfDgqs9ERbZZ3Bi1PNYrCCusFLucT39K525MWLpeURjHwUsfX/1/*)";
+    let watch_only_external_descriptor = "wpkh([e9824965/84'/1'/0']tpubDCcguXsm6uj79fSQt4V2EF7SF5b26zCuG2ZZNsbNQuw5G9YWSJuGhg2KknQBywRq4VGTu41zYTCh3QeVFyBdbsymgRX9Mrts94SW7obEdqs/0/*)";
+    let watch_only_internal_descriptor = "wpkh([e9824965/84'/1'/0']tpubDCcguXsm6uj79fSQt4V2EF7SF5b26zCuG2ZZNsbNQuw5G9YWSJuGhg2KknQBywRq4VGTu41zYTCh3QeVFyBdbsymgRX9Mrts94SW7obEdqs/1/*)";
+
+    // create client for Blockstream's testnet electrum server
+    #[cfg(feature = "electrum")]
+    let blockchain =
+        ElectrumBlockchain::from(Client::new("ssl://electrum.blockstream.info:60002").unwrap());
+
+    // create watch only wallet
+    let watch_only_wallet: Wallet<MemoryDatabase> = Wallet::new(
+        watch_only_external_descriptor,
+        Some(watch_only_internal_descriptor),
+        Network::Testnet,
+        MemoryDatabase::default(),
+    )?;
+
+    // create signing wallet
+    let signing_wallet: Wallet<MemoryDatabase> = Wallet::new(
+        signing_external_descriptor,
+        Some(signing_internal_descriptor),
+        Network::Testnet,
+        MemoryDatabase::default(),
+    )?;
+
+    #[cfg(feature = "electrum")]
+    {
+        println!("Sync watch only wallet");
+        watch_only_wallet.sync(&blockchain, SyncOptions::default())?;
+    }
+
+    // get deposit address
+    let deposit_address = watch_only_wallet.get_address(AddressIndex::New).unwrap();
+    println!(
+        "Fund watch only wallet by sending testnet bitcoin to this address: {addr}\nExplorer URL: https://mempool.space/testnet/address/{addr}",
+        addr = deposit_address.address
+    );
+
+    let balance = watch_only_wallet.get_balance()?;
+    println!("Watch only wallet balance in SAT: {}", balance);
+
+    //Create the PSBT sending 10,000 SATs back to the same wallet
+    let send_to_address = watch_only_wallet.get_address(AddressIndex::New)?;
+    let mut builder = watch_only_wallet.build_tx();
+    builder
+        .add_recipient(send_to_address.script_pubkey(), 10_000)
+        .enable_rbf()
+        .do_not_spend_change()
+        .fee_rate(FeeRate::from_sat_per_vb(1.0));
+
+    match builder.finish() {
+        Ok((mut psbt, details)) => {
+            println!("Transaction details: {:#?}", details);
+            println!("Unsigned PSBT: {}", psbt.to_string());
+
+            // Sign and finalize the PSBT with the signing wallet
+            let finalized = signing_wallet.sign(&mut psbt, SignOptions::default())?;
+            assert!(finalized, "Tx not finalized");
+            println!("The transaction has been signed: {}", finalized);
+
+            #[cfg(feature = "electrum")]
+            {
+                // Broadcast the transaction
+                let raw_transaction = psbt.extract_tx();
+                let txid = raw_transaction.txid();
+
+                blockchain.broadcast(&raw_transaction)?;
+                println!(
+                "Transaction sent! TXID: {txid}.\nExplorer URL: https://mempool.space/testnet/tx/{txid}",
+                txid = txid);
+            }
+        }
+        Err(err) => {
+            println!("Unable to finalize PSBT: {}", err);
+        }
+    }
+
+    Ok(())
+}