Release v0.9.0

By Alekos Filini on 7/12/2021 - Tags: Rust, Release

A new release of BDK is out: v0.9.0 (opens new window) brings support for Bitcoin Core backends, more sanity checks and bugfixes.

You can find the full v0.9.0 changelog (opens new window) on GitHub.

# What's new in v0.9.0

Below are some highlights of the new release:

# Bitcoin Core Blockchain Backend

This release finally adds support for using a Bitcoin Core node as the Blockchain backend for a wallet, through the RPC. This is still considered experimental for the time being, since there are a few missing things that we'd like to add, and adding those could force us to change the API a little.

Nonetheless, if you don't mind a breaking-change later on it's already fully functional.

The backend works by importing addresses in Bitcoin Core using the importmulti call.

Using it is pretty straightforward, here's a quick example:

let config = RpcConfig {
    url: "127.0.0.1:18332".to_string(),
    auth: bitcoincore_rpc::Auth::CookieFile("/home/user/.bitcoin/.cookie".into()),
    network: bdk::bitcoin::Network::Testnet,
    wallet_name: "wallet_name".to_string(),
    skip_blocks: None,
};
let blockchain = RpcBlockchain::from_config(&config);

Similarly to the compact filters backend, the skip_blocks field allows for starting a rescan of the blockchain at a given height rather than the genesis, saving some time. The rescan is only performed once, the first time an address is imported. Afterwards every sync() call will only perform a few queries on the node and it will be much faster.

# Updated TransactionDetails Struct

To better accomodate the Bitcoin Core RPC and potentially more future new backends, the TransactionDetails (opens new window) structure have been updated as follows:

  • The fees field has been renamed to fee and it has been made optional. Blockchain backends can set this to None when they have no way of computing the fee of a transaction
  • The timestamp and height fields have been merged into an optional ConfirmationTime (opens new window) struct

# Verify Downloaded TXs

This release also introduces an opt-in feature called verify that can be enabled to verify the unconfirmed transactions that BDK downloads from untrusted sources like Electrum servers.

Verifying the transactions against the consensus rules can be an additional protection against some kind of attacks that could trick a wallet into creating wrong RBF (BIP 125) "bump" transactions. Check out the issue (opens new window) for more details.

# Contributors

A huge thanks to everybody who contributed to this new release with suggestions, pull requests and bug reports.

Since the v0.8.0 release around a month ago, we've had 45 new commits made by 6 different contributors for a total of 1336 additions and 266 deletions. Here's the full diff (opens new window).

A special thanks to the new contributor for this release:

  • [@jb55][@jb55] - William Casarin