How to get value to put in &[GetBlockTemplateCapabilities] as an argument for get_block_template()?

[matthiasdebernardini]

I am trying to get the block template of my core node so I can implement this in rust.

https://code.samourai.io/oxt/one_dollar_fee_estimator/-/blob/master/one_dollar_fee_estimator/estimator.py

Below is my code that wont compile and I can't figure out how to use the rpc call correctly just from looking at the docs.

How would I supply the get block template call with the correct capabilities? Looks like I need to get a value from the enum to put in the array but I can't figure out how to invoke one from the docs.

This is the function signature that I copied from the docs.
fn get_block_template(
&self,
mode: GetBlockTemplateModes,
rules: &GetBlockTemplateRules[],
capabilities: &GetBlockTemplateCapabilities[]
) -> Result<GetBlockTemplateResult>

This is my code that I am trying to get running.

use std::error::Error;
use bitcoincore_rpc::RpcApi;
fn main() -> Result<(), Box<dyn Error>> {
    let client = bitcoincore_rpc::Client::new("http://127.0.0.1:38333",bitcoincore_rpc::Auth::UserPass("".to_string(), "".to_string()))?;
    let mode = bitcoincore_rpc::json::GetBlockTemplateModes::Template;
    let rules = &[bitcoincore_rpc::json::GetBlockTemplateRules::Signet, bitcoincore_rpc::json::GetBlockTemplateRules::Taproot, bitcoincore_rpc::json::GetBlockTemplateRules::SegWit, bitcoincore_rpc::json::GetBlockTemplateRules::Csv];
    let capabilities = bitcoincore_rpc::json::GetBlockTemplateCapabilities;
    let rpc = client.get_block_template(mode, rules, capabilities);
    Ok(())
}

I also tried lookind up this example but I think its no longer valid (or at least it wont compile for me.

#163 (comment)

this is my cargo.toml for reference

[package]
name = "one-dollar-estimator"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
statistical = "1.0.0"
ringbuf = "0.2.8"
bitcoincore-rpc = "0.14.0"
bitcoincore-rpc-json = "0.14.0"

Appreciate any pointers, not sure what I am doing wrong here.

[0xB10C]

Have a look at e.g.

https://github.com/0xB10C/miningpool-observer/blob/e8eb52dea2c15527c9784fd431b03ac951a44647/daemon/src/main.rs#L233-L239

but I think the result you get form that RPC call to a v0.21 or newer node is currently broken. See #176. I'm running a patched version of this crate as the fix hasn't been merged yet.

[0xB10C]

Also see the integration tests

rust-bitcoincore-rpc/integration_test/src/main.rs

Lines 1122 to 1130 in 657eebd

	fn test_getblocktemplate(cl: &Client) {
	// We want to have a transaction in the mempool so the GetBlockTemplateResult
	// contains an entry in the vector of GetBlockTemplateResultTransaction.
	// Otherwise the GetBlockTemplateResultTransaction deserialization wouldn't
	// be tested.
	cl.send_to_address(&RANDOM_ADDRESS, btc(1), None, None, None, None, None, None).unwrap();
	cl.get_block_template(GetBlockTemplateModes::Template, &[GetBlockTemplateRules::SegWit], &[])
	.unwrap();

[matthiasdebernardini]

@0xB10C thank you very much, I was able to get it running.

I'll share it here for good measure.

If it belongs elsewhere, let me know.

use bitcoincore_rpc::json::GetBlockTemplateModes::Template;
use bitcoincore_rpc::json::GetBlockTemplateRules::{Csv, SegWit, Signet, Taproot};
use bitcoincore_rpc::RpcApi;
use bitcoincore_rpc::{Auth, Client};
use std::error::Error;

fn main() -> Result<(), Box<dyn Error>> {
    let client = Client::new(
        "http://127.0.0.1:38332",
        Auth::UserPass("hello".to_string(), "there".to_string()),
    )?;
    let mode = Template;
    let rules = &[Signet, SegWit, Taproot, Csv];
    let capabilities = &[];
    let rpc = client.get_block_template(mode, rules, capabilities)?;
    rpc.transactions.iter().for_each(|a| println!("{:?}", a));
    Ok(())
}

[0xB10C]

Awesome! Feel free to close this issues if it's solved.