$ npm install @ethereumjs/statemanager
Note: this README has been updated containing the changes from our next breaking release round [UNRELEASED] targeted for Summer 2023. See the README files from the maintenance-v6 branch for documentation matching our latest releases.
Library to provide high level access to Ethereum State |
---|
To obtain the latest version, simply require the project using npm
:
npm install @ethereumjs/statemanager
Note: this library was part of the @ethereumjs/vm package up till VM v5
.
The StateManager
provides high-level access and manipulation methods to and for the Ethereum state, thinking in terms of accounts or contract code rather then the storage operations of the underlying data structure (e.g. a Trie).
The library includes a TypeScript interface StateManager
to ensure a unified interface (e.g. when passed to the VM) as well as a concrete Trie-based implementation DefaultStateManager
as well as an EthersStateManager
implementation that sources state and history data from an external ethers
provider.
It also includes a checkpoint/revert/commit mechanism to either persist or revert state changes and provides a sophisticated caching mechanism under the hood to reduce the need for direct state accesses.
DefaultStateManager
Exampleimport { Account, Address } from '@ethereumjs/util'
import { DefaultStateManager } from '@ethereumjs/statemanager'
import { hexToBytes } from '@ethereumjs/util'
const stateManager = new DefaultStateManager()
const address = new Address(hexToBytes('0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b'))
const account = new Account(BigInt(0), BigInt(1000))
await stateManager.checkpoint()
await stateManager.putAccount(address, account)
await stateManager.commit()
await stateManager.flush()
Starting with the v2 release the StateManager comes with a significantly more elaborate caching mechanism for account and storage caches.
There are now two cache options available: an unbounded cache (CacheType.ORDERED_MAP
) for short-lived usage scenarios (this one is the default cache) and a fixed-size cache (CacheType.LRU
) for a long-lived large cache scenario.
Caches now "survive" a flush operation and especially long-lived usage scenarios will benefit from increased performance by a growing and more "knowing" cache leading to less and less trie reads.
Have a loot at the extended CacheOptions
on how to use and leverage the new cache system.
EthersStateManager
First, a simple example of usage:
import { Account, Address } from '@ethereumjs/util'
import { EthersStateManager } from '@ethereumjs/statemanager'
import { ethers } from 'ethers'
const provider = new ethers.providers.JsonRpcProvider('https://path.to.my.provider.com')
const stateManager = new EthersStateManager({ provider, blockTag: 500000n })
const vitalikDotEth = Address.fromString('0xd8da6bf26964af9d7eed9e03e53415d37aa96045')
const account = await stateManager.getAccount(vitalikDotEth)
console.log('Vitalik has a current ETH balance of ', account.balance)
The EthersStateManager
can be be used with an ethers
JsonRpcProvider
or one of its subclasses. Instantiate the VM
and pass in an EthersStateManager
to run transactions against accounts sourced from the provider or to run blocks pulled from the provider at any specified block height.
Note: Usage of this StateManager can cause a heavy load regarding state request API calls, so be careful (or at least: aware) if used in combination with an Ethers provider connecting to a third-party API service like Infura!
CloudFlareProvider
from the @ethersproject/providers
module to get a quickstart.eth_getProof
, eth_getCode
, and eth_getStorageAt
RPC methods.earliest
in the constructor that specifies the block height you want to pull state from.latest
/pending
values supported by the Ethereum JSON-RPC are not supported as longer running scripts run the risk of state values changing as blocks are mined while your script is running.Refer to this test script for complete examples of running transactions and blocks in the vm
with data sourced from a provider.
With the breaking release round in Summer 2023 we have added hybrid ESM/CJS builds for all our libraries (see section below) and have eliminated many of the caveats which had previously prevented a frictionless browser usage.
It is now easily possible to run a browser build of one of the EthereumJS libraries within a modern browser using the provided ESM build. For a setup example see ./examples/browser.html.
Generated TypeDoc API Documentation
With the breaking releases from Summer 2023 we have started to ship our libraries with both CommonJS (cjs
folder) and ESM builds (esm
folder), see package.json
for the detailed setup.
If you use an ES6-style import
in your code files from the ESM build will be used:
import { EthereumJSClass } from '@ethereumjs/[PACKAGE_NAME]'
If you use Node.js specific require
the CJS build will be used:
const { EthereumJSClass } = require('@ethereumjs/[PACKAGE_NAME]')
Using ESM will give you additional advantages over CJS beyond browser usage like static code analysis / Tree Shaking which CJS can not provide.
With the breaking releases from Summer 2023 we have removed all Node.js specific Buffer
usages from our libraries and replace these with Uint8Array representations, which are available both in Node.js and the browser (Buffer
is a subclass of Uint8Array
).
We have converted existing Buffer conversion methods to Uint8Array conversion methods in the @ethereumjs/util bytes
module, see the respective README section for guidance.
Starting with v1 the usage of BN.js for big numbers has been removed from the library and replaced with the usage of the native JS BigInt data type (introduced in ES2020
).
Please note that number-related API signatures have changed along with this version update and the minimal build target has been updated to ES2020
.
Developer documentation - currently mainly with information on testing and debugging - can be found here.
See our organizational documentation for an introduction to EthereumJS
as well as information on current standards and best practices. If you want to join for work or carry out improvements on the libraries, please review our contribution guidelines first.
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