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Getting started

Overview

Alephium proposes multiple tools and packages to help you build your dApps.

This guide will help you install our recommended setup.

Prerequisites

Info

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Create a new dApp project

To create the tutorial project, open a new terminal and run:

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npx @alephium/cli@latest init alephium-tutorial

This will create a new directory alephium-tutorial and initialize a sample project inside that directory.

Launch the local development network

To compile and test your contracts, it's necessary to launch a local development network, and you can follow this guide to launch a devnet.

Your new network is now launched using this configuration and generated addresses in 4 groups with enough ALPHs for testing purposes.

The Typescript SDK is then able to interact with the network through REST endpoints.

Compile your contract

Next, change the workspace to the tutorial project:

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cd alephium-tutorial

Have a look in the contracts/ folder, you can find token.ral and withdraw.ral:

token.ral
Rust
import "std/fungible_token_interface"

// Defines a contract named `TokenFaucet`.
// A contract is a collection of fields (its state) and functions.
// Once deployed, a contract resides at a specific address on the Alephium blockchain.
// Contract fields are permanently stored in contract storage.
// A contract can issue an initial amount of token at its deployment.
Contract TokenFaucet(
    symbol: ByteVec,
    name: ByteVec,
    decimals: U256,
    supply: U256,
    mut balance: U256
) implements IFungibleToken {

    // Events allow for logging of activities on the blockchain.
    // Alephium clients can listen to events in order to react to contract state changes.
    event Withdraw(to: Address, amount: U256)

    enum ErrorCodes {
        InvalidWithdrawAmount = 0
    }

    // A public function that returns the initial supply of the contract's token.
    // Note that the field must be initialized as the amount of the issued token.
    pub fn getTotalSupply() -> U256 {
        return supply
    }

    // A public function that returns the symbol of the token.
    pub fn getSymbol() -> ByteVec {
        return symbol
    }

    // A public function that returns the name of the token.
    pub fn getName() -> ByteVec {
        return name
    }

    // A public function that returns the decimals of the token.
    pub fn getDecimals() -> U256 {
        return decimals
    }

    // A public function that returns the current balance of the contract.
    pub fn balance() -> U256 {
        return balance
    }

    // A public function that transfers tokens to anyone who calls it.
    // The function is annotated with `updateFields = true` as it changes the contract fields.
    // The function is annotated as using contract assets as it does.
    @using(assetsInContract = true, updateFields = true, checkExternalCaller = false)
    pub fn withdraw(amount: U256) -> () {
        // Debug events can be helpful for error analysis
        emit Debug(`The current balance is ${balance}`)

        // Make sure the amount is valid
        assert!(amount <= 2, ErrorCodes.InvalidWithdrawAmount)
        // Functions postfixed with `!` are built-in functions.
        transferTokenFromSelf!(callerAddress!(), selfTokenId!(), amount)
        // Ralph does not allow underflow.
        balance = balance - amount

        // Emit the event defined earlier.
        emit Withdraw(callerAddress!(), amount)
    }
}
withdraw.ral
Rust
// Defines a transaction script.
// A transaction script is a piece of code to interact with contracts on the blockchain.
// Transaction scripts can use the input assets of transactions in general.
// A script is disposable and will only be executed once along with the holder transaction.
TxScript Withdraw(token: TokenFaucet, amount: U256) {
    // Call token contract's withdraw function.
    token.withdraw(amount)
}

To compile your contracts, run:

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npx @alephium/cli@latest compile

The compiled artifacts are in the directory artifacts.

This command also generates typescript code based on the compiled artifacts. The generated typescript code are in the directory artifacts/ts. You can interact with the alephium blockchain more conveniently by using the generated typescript code.

Test your contract

The sample project comes with tests test/unit/token.test.ts for your contract:

token.test.ts
TypeScript
import { web3, Project, TestContractParams, addressFromContractId, AssetOutput, DUST_AMOUNT } from '@alephium/web3'
import { expectAssertionError, randomContractId, testAddress, testNodeWallet } from '@alephium/web3-test'
import { deployToDevnet } from '@alephium/cli'
import { TokenFaucet, TokenFaucetTypes, Withdraw } from '../artifacts/ts'

describe('unit tests', () => {
  let testContractId: string
  let testTokenId: string
  let testContractAddress: string
  let testParamsFixture: TestContractParams<TokenFaucetTypes.Fields, { amount: bigint }>

  // We initialize the fixture variables before all tests
  beforeAll(async () => {
    web3.setCurrentNodeProvider('http://127.0.0.1:22973')
    await Project.build()
    testContractId = randomContractId()
    testTokenId = testContractId
    testContractAddress = addressFromContractId(testContractId)
    testParamsFixture = {
      // a random address that the test contract resides in the tests
      address: testContractAddress,
      // assets owned by the test contract before a test
      initialAsset: { alphAmount: 10n ** 18n, tokens: [{ id: testTokenId, amount: 10n }] },
      // initial state of the test contract
      initialFields: {
        symbol: Buffer.from('TF', 'utf8').toString('hex'),
        name: Buffer.from('TokenFaucet', 'utf8').toString('hex'),
        decimals: 18n,
        supply: 10n ** 18n,
        balance: 10n
      },
      // arguments to test the target function of the test contract
      testArgs: { amount: 1n },
      // assets owned by the caller of the function
      inputAssets: [{ address: testAddress, asset: { alphAmount: 10n ** 18n } }]
    }
  })
  //See more test in `test/unit/token.test.ts`
})

You can run them with:

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npm run test

or

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npx @alephium/cli@latest test

Deploy your contract

Next, to deploy the contract we will use Alephium CLI and a deployment script scripts/0_deploy_faucet.ts:

0_deploy_faucet.ts
TypeScript
import { Deployer, DeployFunction, Network } from '@alephium/cli'
import { Settings } from '../alephium.config'
import { TokenFaucet } from '../artifacts/ts'

// This deploy function will be called by cli deployment tool automatically
// Note that deployment scripts should prefixed with numbers (starting from 0)
const deployFaucet: DeployFunction<Settings> = async (
  deployer: Deployer,
  network: Network<Settings>
): Promise<void> => {
  // Get settings
  const issueTokenAmount = network.settings.issueTokenAmount
  const result = await deployer.deployContract(TokenFaucet, {
    // The amount of token to be issued
    issueTokenAmount: issueTokenAmount,
    // The initial states of the faucet contract
    initialFields: {
      symbol: Buffer.from('TF', 'utf8').toString('hex'),
      name: Buffer.from('TokenFaucet', 'utf8').toString('hex'),
      decimals: 18n,
      supply: issueTokenAmount,
      balance: issueTokenAmount
    }
  })
  console.log('Token faucet contract id: ' + result.contractInstance.contractId)
  console.log('Token faucet contract address: ' + result.contractInstance.address)
}

export default deployFaucet

You can run it using:

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npx @alephium/cli@latest deploy

This will deploy the token faucet to group 0 of devnet. To deploy on testnet (or any other network), update your alephium.config.ts and use the --network option:

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npx @alephium/cli@latest deploy --network testnet

Interact with the deployed contract

Now, you can build the source code src/token.ts :

token.ts
TypeScript
import { Deployments } from '@alephium/cli'
import { DUST_AMOUNT, web3, Project } from '@alephium/web3'
import { testNodeWallet } from '@alephium/web3-test'
import configuration from '../alephium.config'
import { TokenFaucet, Withdraw } from '../artifacts/ts'

async function withdraw() {
  web3.setCurrentNodeProvider('http://127.0.0.1:22973')
  // Compile the contracts of the project if they are not compiled
  Project.build()

  // Attention: test wallet is used for demonstration purpose
  const signer = await testNodeWallet()

  const deployments = await Deployments.load(configuration, 'devnet')

  // The test wallet has four accounts with one in each address group
  // The wallet calls withdraw function for all of the address groups
  for (const account of await signer.getAccounts()) {
    // Set an active account to prepare and sign transactions
    await signer.setSelectedAccount(account.address)
    const accountGroup = account.group

    // Load the metadata of the deployed contract in the right group
    const deployed = deployments.getDeployedContractResult(accountGroup, 'TokenFaucet')
    if (deployed === undefined) {
      console.log(`The contract is not deployed on group ${account.group}`)
      continue
    }
    const tokenId = deployed.contractInstance.contractId
    const tokenAddress = deployed.contractInstance.address

    // Submit a transaction to use the transaction script
    await Withdraw.execute(signer, {
      initialFields: { token: tokenId, amount: 1n },
      attoAlphAmount: DUST_AMOUNT
    })

    const faucet = TokenFaucet.at(tokenAddress)
    // Fetch the latest state of the token contract
    const state = await faucet.fetchState()
    console.log(JSON.stringify(state.fields, null, '  '))
  }
}

withdraw()

Simply run:

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npm run build

and interact with the deployed token faucet:

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node dist/src/token.js

Connect to the wallets

dApp requires wallet integration for users of the dApp to authenticate and interact with the Alephium blockchain, such as transactions signing. Currently dApps can be integrated with both Extension Wallet and WalletConnect. Please refer to the respective pages for more details.

Learn more