GUIDELINE 08

Plan storage and rent early

Create asset metadata and its rent relationship before uploading bytes, and decide who owns, funds, upgrades, and deletes the object.

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Choose the lifecycle

Direct rent-funded asset: create_tx_asset_deploy authenticates the rent key and creates the metadata directly.
Contract-funded asset: a normal contract call can create the file modification using the contract's configured rent wallet.
Caller-funded contract asset: create_tx_contract_call_with_rent authenticates a caller-supplied rent override while the contract validates and creates the asset metadata.
Permanent: use an empty authenticated wallet and a contract modification with make_permanent, or use create_tx_make_permanent for an existing asset, only after estimating the full cost.

Required checks

Derive and initialize the rent wallet predictably.
Hash bytes locally and keep filename, MIME type, byte length, and owner explicit.
Wait for successful metadata creation before upload_asset.
Treat upload success and transaction execution as separate states.
Expose rent depletion, permanence, transfer, upgrade, and deletion behavior in the UI.

Rent-funded direct asset

const bytes = new Uint8Array(await file.arrayBuffer());
const rent = await deriveRentWallet();
const asset = await deriveAssetWallet(fileId);
const submitFinal = tx => new Promise((resolve, reject) => {
  itza.submit_tx_with_result(tx, event => {
    try { ensureWasmSucceeded(event); resolve(event); } catch (error) { reject(error); }
  }).catch(reject);
});

// Start this deterministic rent wallet once; tolerate "already exists".
await submitFinal(itza.create_tx_rent_start(rent.keypair));

const tx = itza.create_tx_asset_deploy(
  asset.keypair, file.name, file.type || "application/octet-stream",
  rent.keypair, wallet.address, bytes, 4, "ssd"
);
renderAssetCreation(await submitFinal(tx));

// Upload only after asset metadata has been accepted.
await itza.upload_asset(asset.address, bytes);

Bottom line

Storage is a lifecycle, not one upload call. Model metadata creation, byte upload, funding, ownership, and deletion as separate observable steps.