bitcoin-s/website/versioned_docs/version-0.5.0/rpc/bitcoind.md
2021-02-03 17:23:06 -06:00

133 lines
4.2 KiB
Markdown

---
id: version-0.5.0-rpc-bitcoind
title: bitcoind/Bitcoin Core
original_id: rpc-bitcoind
---
## Downloading bitcoind
The Bitcoin Core RPC client in Bitcoin-S currently supports the Bitcoin Core
- 0.16
- 0.17
- 0.18
- 0.19
- 0.20
- 0.21
version lines. It can be set up to work with both local and remote Bitcoin Core servers.
You can fetch them using bitcoin-s by running the following sbt command. If you already have bitcoind installed on your machine, you can skip this step.
```bash
sbt downloadBitcoind
```
The binaries will be stored in `~/.bitcoin-s/binaries/bitcoind/`
## Connecting to a local `bitcoind` instance
### Getting started quickly, with default options:
```scala
implicit val ec: ExecutionContext = ExecutionContext.global
// this reads authentication credentials and
// connection details from the default data
// directory on your platform
val client = BitcoindRpcClient.fromDatadir(binary=new File("/path/to/bitcoind"), datadir=new File("/path/to/bitcoind-datadir"))
val balance: Future[Bitcoins] = for {
_ <- client.start()
balance <- client.getBalance
} yield balance
```
## Multi-wallet `bitcoind` instances
When using the `bitcoind` with multiple wallets you will need to specify the wallet's name.
To do so the wallet rpc functions have an optional `walletName` parameter.
```scala
implicit val ec: ExecutionContext = ExecutionContext.global
val client = BitcoindRpcClient.fromDatadir(binary=new File("/path/to/bitcoind"), datadir=new File("/path/to/bitcoind-datadir"))
for {
_ <- client.start()
_ <- client.walletPassphrase("mypassword", 10000, Some("walletName"))
balance <- client.getBalance("walletName")
} yield ()
```
## Connecting to a remote `bitcoind`
First, we create a secure connection to our `bitcoind` instance by setting
up a SSH tunnel:
```bash
ssh -L 8332:localhost:8332 my-cool-user@my-cool-website.com
```
> Note: the port number '8332' is the default for mainnet. If you want to
> connect to a testnet `bitcoind`, the default port is '18332'
Now that we have a secure connection between our remote `bitcoind`, we're
ready to create the connection with our RPC client
```scala
implicit val ec: ExecutionContext = ExecutionContext.global
val username = "FILL_ME_IN" //this username comes from 'rpcuser' in your bitcoin.conf file //this username comes from 'rpcuser' in your bitcoin.conf file
val password = "FILL_ME_IN" //this password comes from your 'rpcpassword' in your bitcoin.conf file //this password comes from your 'rpcpassword' in your bitcoin.conf file
val authCredentials = BitcoindAuthCredentials.PasswordBased(
username = username,
password = password
)
val bitcoindInstance = {
BitcoindInstance (
network = MainNet,
uri = new URI(s"http://localhost:${MainNet.port}"),
rpcUri = new URI(s"http://localhost:${MainNet.rpcPort}"),
authCredentials = authCredentials
)
}
val rpcCli = BitcoindRpcClient(bitcoindInstance)
rpcCli.getBalance.onComplete { case balance =>
println(s"Wallet balance=${balance}")
}
```
## Error handling
All errors returned by Bitcoin Core are mapped to a corresponding
[`BitcoindException`](https://github.com/bitcoin-s/bitcoin-s/blob/master/bitcoind-rpc/src/main/scala/org/bitcoins/rpc/BitcoindException.scala).
These exceptions contain an error code and a message. `BitcoindException` is a sealed
trait, which means you can easily pattern match exhaustively. Of course, other errors
could also happen: network errors, stack overflows or out-of-memory errors. The provided
class is only intended to cover errors returned by Bitcoin Core. An example of how error
handling could look:
```scala
implicit val ec = ExecutionContext.global
// let's assume you have an already running client,
// so there's no need to start this one
val cli = BitcoindRpcClient.fromDatadir(binary=new File("/path/to/bitcoind"), datadir=new File("/path/to/bitcoind-datadir"))
// let's also assume you have a bitcoin address
val address: BitcoinAddress = ???
val txid: Future[DoubleSha256DigestBE] =
cli.sendToAddress(address, 3.bitcoins).recoverWith {
case BitcoindWalletException.UnlockNeeded(_) =>
cli.walletPassphrase("my_passphrase", 60).flatMap { _ =>
cli.sendToAddress(address, 3.bitcoins)
}
}
```