bdk/src/wallet/address_validator.rs
LLFourn 326bfe82a8
Remove Blockchain from wallet
Although somewhat convenient to have, coupling the Wallet with
the blockchain trait causes development friction and complexity.
What if sometimes the wallet is "offline" (no access to the blockchain)
but sometimes its online?
The only thing the Wallet needs the blockchain for is to sync.
But not all applications will even use the sync method and the sync
method doesn't require the full blockchain functionality.
So we instead pass the blockchain in when we want to sync.

- To further reduce the coupling with blockchain I removed the get_height call from `new` and just use the height of the
last sync in the database.
- I split up the blockchain trait a bit into subtraits.
2022-02-24 20:39:00 +11:00

155 lines
5.2 KiB
Rust

// Bitcoin Dev Kit
// Written in 2020 by Alekos Filini <alekos.filini@gmail.com>
//
// 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.
//! Address validation callbacks
//!
//! The typical usage of those callbacks is for displaying the newly-generated address on a
//! hardware wallet, so that the user can cross-check its correctness.
//!
//! More generally speaking though, these callbacks can also be used to "do something" every time
//! an address is generated, without necessarily checking or validating it.
//!
//! An address validator can be attached to a [`Wallet`](super::Wallet) by using the
//! [`Wallet::add_address_validator`](super::Wallet::add_address_validator) method, and
//! whenever a new address is generated (either explicitly by the user with
//! [`Wallet::get_address`](super::Wallet::get_address) or internally to create a change
//! address) all the attached validators will be polled, in sequence. All of them must complete
//! successfully to continue.
//!
//! ## Example
//!
//! ```
//! # use std::sync::Arc;
//! # use bitcoin::*;
//! # use bdk::address_validator::*;
//! # use bdk::database::*;
//! # use bdk::*;
//! # use bdk::wallet::AddressIndex::New;
//! #[derive(Debug)]
//! struct PrintAddressAndContinue;
//!
//! impl AddressValidator for PrintAddressAndContinue {
//! fn validate(
//! &self,
//! keychain: KeychainKind,
//! hd_keypaths: &HdKeyPaths,
//! script: &Script
//! ) -> Result<(), AddressValidatorError> {
//! let address = Address::from_script(script, Network::Testnet)
//! .as_ref()
//! .map(Address::to_string)
//! .unwrap_or(script.to_string());
//! println!("New address of type {:?}: {}", keychain, address);
//! println!("HD keypaths: {:#?}", hd_keypaths);
//!
//! Ok(())
//! }
//! }
//!
//! let descriptor = "wpkh(tpubD6NzVbkrYhZ4Xferm7Pz4VnjdcDPFyjVu5K4iZXQ4pVN8Cks4pHVowTBXBKRhX64pkRyJZJN5xAKj4UDNnLPb5p2sSKXhewoYx5GbTdUFWq/*)";
//! let mut wallet = Wallet::new(descriptor, None, Network::Testnet, MemoryDatabase::default())?;
//! wallet.add_address_validator(Arc::new(PrintAddressAndContinue));
//!
//! let address = wallet.get_address(New)?;
//! println!("Address: {}", address);
//! # Ok::<(), bdk::Error>(())
//! ```
use std::fmt;
use bitcoin::Script;
use crate::descriptor::HdKeyPaths;
use crate::types::KeychainKind;
/// Errors that can be returned to fail the validation of an address
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AddressValidatorError {
/// User rejected the address
UserRejected,
/// Network connection error
ConnectionError,
/// Network request timeout error
TimeoutError,
/// Invalid script
InvalidScript,
/// A custom error message
Message(String),
}
impl fmt::Display for AddressValidatorError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{:?}", self)
}
}
impl std::error::Error for AddressValidatorError {}
/// Trait to build address validators
///
/// All the address validators attached to a wallet with [`Wallet::add_address_validator`](super::Wallet::add_address_validator) will be polled
/// every time an address (external or internal) is generated by the wallet. Errors returned in the
/// validator will be propagated up to the original caller that triggered the address generation.
///
/// For a usage example see [this module](crate::address_validator)'s documentation.
pub trait AddressValidator: Send + Sync + fmt::Debug {
/// Validate or inspect an address
fn validate(
&self,
keychain: KeychainKind,
hd_keypaths: &HdKeyPaths,
script: &Script,
) -> Result<(), AddressValidatorError>;
}
#[cfg(test)]
mod test {
use std::sync::Arc;
use super::*;
use crate::wallet::AddressIndex::New;
use crate::wallet::{get_funded_wallet, test::get_test_wpkh};
#[derive(Debug)]
struct TestValidator;
impl AddressValidator for TestValidator {
fn validate(
&self,
_keychain: KeychainKind,
_hd_keypaths: &HdKeyPaths,
_script: &bitcoin::Script,
) -> Result<(), AddressValidatorError> {
Err(AddressValidatorError::InvalidScript)
}
}
#[test]
#[should_panic(expected = "InvalidScript")]
fn test_address_validator_external() {
let (mut wallet, _, _) = get_funded_wallet(get_test_wpkh());
wallet.add_address_validator(Arc::new(TestValidator));
wallet.get_address(New).unwrap();
}
#[test]
#[should_panic(expected = "InvalidScript")]
fn test_address_validator_internal() {
let (mut wallet, descriptors, _) = get_funded_wallet(get_test_wpkh());
wallet.add_address_validator(Arc::new(TestValidator));
let addr = crate::testutils!(@external descriptors, 10);
let mut builder = wallet.build_tx();
builder.add_recipient(addr.script_pubkey(), 25_000);
builder.finish().unwrap();
}
}