The ViewOnlyAccount trait provides a common interface to query balances.
The Account trait, in addition to the above, also provides a common interface to retrieve spendable resources or transfer assets. When performing actions in the SDK that lead to a transaction, you will typically need to provide an account that will be used to allocate resources required by the transaction, including transaction fees.
Both traits are implemented by the following types:
An account implements the following methods for transferring assets:
transfer force_transfer_to_contract withdraw_to_base_layer The following examples are provided for a Wallet account. A Predicate account would work similarly, but you might need to set its predicate data before attempting to spend resources owned by it.
With wallet.transfer you can initiate a transaction to transfer an asset from your account to a target address.
use fuels::prelude::*;
// Setup 2 test wallets with 1 coin each
let num_wallets = Some(2);
let coins_per_wallet = Some(1);
let coin_amount = Some(1);
let wallets = launch_custom_provider_and_get_wallets(
WalletsConfig::new(num_wallets, coins_per_wallet, coin_amount),
None,
None,
)
.await?;
// Transfer the base asset with amount 1 from wallet 1 to wallet 2
let asset_id = Default::default();
let (_tx_id, _receipts) = wallets[0]
.transfer(wallets[1].address(), 1, asset_id, TxPolicies::default())
.await?;
let wallet_2_final_coins = wallets[1].get_coins(AssetId::zeroed()).await?;
// Check that wallet 2 now has 2 coins
assert_eq!(wallet_2_final_coins.len(), 2);
You can transfer assets to a contract via wallet.force_transfer_to_contract.
// Check the current balance of the contract with id 'contract_id'
let contract_balances = wallet
.try_provider()?
.get_contract_balances(&contract_id)
.await?;
assert!(contract_balances.is_empty());
// Transfer an amount of 300 to the contract
let amount = 300;
let asset_id = random_asset_id;
let (_tx_id, _receipts) = wallet
.force_transfer_to_contract(&contract_id, amount, asset_id, TxPolicies::default())
.await?;
// Check that the contract now has 1 coin
let contract_balances = wallet
.try_provider()?
.get_contract_balances(&contract_id)
.await?;
assert_eq!(contract_balances.len(), 1);
let random_asset_balance = contract_balances.get(&random_asset_id).unwrap();
assert_eq!(*random_asset_balance, 300); For transferring assets to the base layer chain, you can use wallet.withdraw_to_base_layer.
use std::str::FromStr;
use fuels::prelude::*;
let wallets = launch_custom_provider_and_get_wallets(
WalletsConfig::new(Some(1), None, None),
None,
None,
)
.await?;
let wallet = wallets.first().unwrap();
let amount = 1000;
let base_layer_address = Address::from_str(
"0x4710162c2e3a95a6faff05139150017c9e38e5e280432d546fae345d6ce6d8fe",
)?;
let base_layer_address = Bech32Address::from(base_layer_address);
// Transfer an amount of 1000 to the specified base layer address
let (tx_id, msg_id, _receipts) = wallet
.withdraw_to_base_layer(&base_layer_address, amount, TxPolicies::default())
.await?;
let _block_height = wallet.try_provider()?.produce_blocks(1, None).await?;
// Retrieve a message proof from the provider
let proof = wallet
.try_provider()?
.get_message_proof(&tx_id, &msg_id, None, Some(2))
.await?
.expect("failed to retrieve message proof");
// Verify the amount and recipient
assert_eq!(proof.amount, amount);
assert_eq!(proof.recipient, base_layer_address); The above example creates an Address from a string and converts it to a Bech32Address. Next, it calls wallet.withdraw_to_base_layer by providing the address, the amount to be transferred, and the transaction policies. Lastly, to verify that the transfer succeeded, the relevant message proof is retrieved with provider.get_message_proof, and the amount and the recipient are verified.