Move Bytecode Template

Move Bytecode Template allows updating a pre-compiled bytecode, so that a standard template could be customized and used to publish new modules on Sui directly in the browser. Hence, removing the need for a backend to compile new modules.

This crate builds a WASM binary for the move-language/move-binary-format allowing bytecode serialization and deserialization in various environments. The main target for this package is "web".

Applications

This package is a perfect fit for the following applications:

• Publishing new Coins
• Publishing TransferPolicies
• Initializing any base type with a custom sub-type

Example of a Template Module

The following code is a close-copy of the Coin example from the Move by Example book.

module 0x0::template {
    use std::option;
    use sui::coin;
    use sui::transfer;
    use sui::tx_context::{Self, TxContext};

    /// The OTW for the Coin
    struct TEMPLATE has drop {}

    const DECIMALS: u8 = 6;
    const SYMBOL: vector<u8> = b"TMPL";
    const NAME: vector<u8> = b"Template Coin";
    const DESCRIPTION: vector<u8> = b"Template Coin Description";

    /// Init the Coin
    fun init(witness: TEMPLATE, ctx: &mut TxContext) {
        let (treasury, metadata) = coin::create_currency(
            witness, DECIMALS, SYMBOL, NAME, DESCRIPTION, option::none(), ctx
        );

        transfer::public_transfer(treasury, tx_context::sender(ctx));
        transfer::public_transfer(metadata, tx_context::sender(ctx));
    }
}

To update the identifiers, you can use the update_identifiers function.

import { fromHex, update_identifiers } from '@mysten/move-bytecode-template';

let bytecode = /* ... */;
let updated = update_identifiers(bytecode, {
    "TEMPLATE": "MY_MODULE",
    "template": "my_module"
});

console.assert(updated != bytecode, 'identifiers were not updated!');

To update constants in the bytecode, you can use the update_constants function. For each constant you need to supply new value as BCS bytes, existing value as BCS, and the type of the constant (as a string: U8, U16 ... U256, Address, Vector(U8) and so on).

import { bcs } from '@mysten/bcs';
import * as template from '@mysten/move-bytecode-template';

// please, manually scan the existing values, this operation is very sensitive
console.log(template.get_constants(bytecode));

let updated;

// Update DECIMALS
updated = update_constants(
	bytecode,
	bcs.u8().serialize(3).toBytes(), // new value
	bcs.u8().serialize(6).toBytes(), // current value
	'U8', // type of the constant
);

// Update SYMBOL
updated = update_constants(
	updated,
	bcs.vector(bcs.string()).serialize('MYC').toBytes(), // new value
	bcs.vector(bcs.string()).serialize('TMPL').toBytes(), // current value
	'Vector(U8)', // type of the constant
);

// Update NAME
updated = update_constants(
	updated,
	bcs.vector(bcs.string()).serialize('My Coin').toBytes(), // new value
	bcs.vector(bcs.string()).serialize('Template Coin').toBytes(), // current value
	'Vector(U8)', // type of the constant
);

Usage in Web applications

The package consists of code and a wasm binary. While the former can be imported directly, the latter should be made available in static / public assets as a Web application. Initialization needs to be performed via a URL, and once completed, other functions become available.

import init, initSync, * as template from '@mysten/move-bytecode-template';

await init('path/to/move_binary_format_bg.wasm');
// alternatively initSync(...);

let version = template.version();
let json = template.deserialize(fromHex('a11ceb0b06....'));
let bytes = template.serialize(json);

console.assert(json == bytes, '(de)serialization failed!');

Using with Vite

To use this package with Vite, you need to import the source file and the wasm binary.

import init, * as template from '@mysten/move-bytecode-template';
import url from '@mysten/move-bytecode-template/move_bytecode_template_bg.wasm?url';

Later, you can initialize the package with the URL.

await init(url);

Lastly, once the package is initialized, you can use the functions as described in the previous section.

const templateBytecode = fromHex('a11ceb0b06....');

template.deserialize(templateBytecode);
template.version();
template.update_identifiers(templateBytecode, {
	TEMPLATE: 'MY_MODULE',
	template: 'my_module',
});

Build locally

To build the binary, you need to have Rust installed and then the wasm-pack. The installation script can be found here.

Building for test (nodejs) environment - required for tests.

pnpm build:dev

Building for web environment.

pnpm build:release

Running tests

Local tests can only be run on the dev build. To run tests, follow these steps:

pnpm build:dev
pnpm test