Wednesday, September 28, 2022

How to query account balance on Solana using Rust.

This post shows how to query Solana's cluster rpc endpoint using Rust. Most of the examples of how to perform this task that I ran to uses Javascript/Typescript via the Solana Web3js library, so I decided to do a quick post showing how to do same but in Rust. It uses querying for the sol balance of a Solana account as the main example of interaction with the rpc endpoint.

The task is simple: given a Solana address, we retrieve the sol balance for that address.

To get started we will need the following dependencies:

solana-client = "1.14.3" // update to the current latest version
solana-sdk = "1.14.3" // update to the current latest version

The code snippet below then shows how to call the rpc endpoint and retrieve the Sol balance for an account

use solana_client::rpc_client::RpcClient;
use solana_program::pubkey::Pubkey;
use std::str::FromStr;

fn main() {
 let rpc = RpcClient::new("");
 let pubkey_str = "4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU";

 let balance = rpc

 println!("Sol balance of {pubkey_str} is {balance}");

Solana addresses are base58 encoded strings, hence they need to be first converted into an instance of Pubkey before they can be used in the rpc.get_account call, which expects a &[u8] byte array. To help with this conversion, Pubkey implements the std::str::FromStr trait. This wmeans, if the trait std::str::FromStr is in scope, then it is possible to convert a string to Pubkey, which is what was done in the code snippet above.

This post was inspired by a recent question I answered on Solana stack exchange here. The answer also mentions another verbose alternative that involves manually converting from base58 to bytes array.