Custom Ledger Entries Retrieval

Do not rely on the Soroban SDK host environment helpers inside long loops such as for example ledger iterations. Working with data in such loops must currently be done with raw XDR structures.

Reading from the ledger is the same as in Accessing the Ledger:

use serde::{Deserialize, Serialize};
use zephyr_sdk::{prelude::*, soroban_sdk::{self, contracttype, String as SorString, Address}, EnvClient};

#[contracttype]
pub enum DataKey {
    Balance(Address)
}
#[derive(Serialize, Deserialize)]
pub struct Balance {
    addr: String,
    balance: i128
}
#[derive(Serialize, Deserialize)]
pub struct Request {
    addesses: Vec<String>
}

#[no_mangle]
pub extern "C" fn get_all_balances() {
    let env = EnvClient::empty();
    let req: Request = env.read_request_body();
    let mut balances = Vec::new();
    for addr in req.addesses {
        let source_addr = Address::from_string(&SorString::from_str(&env.soroban(), &addr));
        let res: i128 = env.read_contract_entry_by_key([0;32], DataKey::Balance(source_addr)).unwrap().unwrap();
        balances.push(Balance { addr, balance: res })
    }

    env.conclude(balances)
}