add esplora_backend example.

Author: w0xlt

Cargo.toml

@@ -121,6 +121,11 @@ name = "electrum_backend"
 path = "examples/electrum_backend.rs"
 required-features = ["electrum"]
 
+[[example]]
+name = "esplora_backend"
+path = "examples/esplora_backend.rs"
+required-features = ["use-esplora-reqwest", "reqwest-default-tls"]
+
 [workspace]
 members = ["macros"]
 [package.metadata.docs.rs]

examples/esplora_backend.rs

@@ -0,0 +1,82 @@
+use std::str::FromStr;
+
+use bdk::{database::MemoryDatabase, blockchain::esplora::EsploraBlockchain, Wallet, KeychainKind, template::Bip84, SyncOptions, wallet::{AddressIndex, export::FullyNodedExport}};
+use bitcoin::{Network, util::bip32::{ExtendedPrivKey, self}};
+use bdk::blockchain::Blockchain;
+
+pub mod utils;
+
+use crate::utils::tx::build_signed_tx;
+
+/// This will create a wallet from an xpriv and get the balance by connecting to an Esplora server.
+/// If enough amount is available, this will send a transaction to an address.
+/// Otherwise, this will display a wallet address to receive funds.
+///
+/// This can be run with `cargo run --features="use-esplora-ureq" --example esplora_backend` in the root folder.
+///
+/// The configuration above uses asynchronous HTTP calls.
+/// To run it in a synchronous way, the user should change `required-features` to
+/// `required-features = ["use-esplora-ureq"] in `esplora_backend` target in Cargo.toml and run
+/// `cargo run --features="use-esplora-ureq" --example esplora_backend`
+fn main() {
+    let network = Network::Signet;
+
+    let xpriv = "tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy";
+
+    let esplora_url = "https://explorer.bc-2.jp/api";
+
+    run(&network, esplora_url, xpriv);
+}
+
+pub fn create_wallet(
+    network: &Network,
+    xpriv: &ExtendedPrivKey
+) -> Wallet<MemoryDatabase> {
+    let wallet = Wallet::new(
+        Bip84(*xpriv, KeychainKind::External),
+        Some(Bip84(*xpriv, KeychainKind::Internal)),
+        *network,
+        MemoryDatabase::default()
+    )
+    .unwrap();
+
+    wallet
+}
+pub fn run(network: &Network, esplora_url: &str, xpriv: &str) {
+    let xpriv = bip32::ExtendedPrivKey::from_str(xpriv).unwrap();
+
+    let blockchain = EsploraBlockchain::new(esplora_url, 20);
+
+    let wallet = load_or_create_wallet(&network, &xpriv);
+
+    wallet.sync(&blockchain, SyncOptions::default()).unwrap();
+
+    let address = wallet.get_address(AddressIndex::New).unwrap().address;
+
+    println!("address: {}", address);
+
+    let balance = wallet.get_balance().unwrap();
+
+    println!("balance: {}", balance);
+
+    if balance > 10500 {
+        // the wallet sends the amount to itself.
+        let recipient_address = wallet.get_address(AddressIndex::New).unwrap().address.to_string();
+
+        let amount = 9359;
+
+        let tx = build_signed_tx(&wallet, &recipient_address, amount);
+
+        blockchain.broadcast(&tx).unwrap();
+
+        println!("tx id: {}", tx.txid().to_string());
+    } else {
+        println!("Insufficient Funds. Fund the wallet with the address above");
+    }
+
+    let export = FullyNodedExport::export_wallet(&wallet, "exported wallet", true)
+        .map_err(ToString::to_string)
+        .map_err(bdk::Error::Generic).unwrap();
+
+    println!("------\nWallet Backup: {}", export.to_string());
+}