hscs/createSmartContract

How to call the API from an app

Hedera Wallet Snap connects to your currently connected Metamask account by default. To learn how apps can connect to Hedera Wallet Snap using a non-metamask(external) account, refer to this documentation.

Then, depending on whether you're trying to connect to a metamask account or a non-metamask account, you can call the snap API in the following way:

const snapId = `npm:@hashgraph/hedera-wallet-snap`

type SmartContractFunctionParameter = {
    type: 'string' | 'bytes' | 'boolean' | 'int' | 'uint';
    value: string | number | boolean | Uint8Array;
}

const createTokenAPI = async () => {
  const externalAccountParams = {
    externalAccount: {
      accountIdOrEvmAddress: '0.0.12345',
      curve: 'ED25519'
    }
  }

  await window.ethereum.request({
    method: 'wallet_invokeSnap',
    params: {
      snapId,
      request: {
        method: 'hscs/createSmartContract',
        params: {
          network: 'testnet',
          gas: 100000,
          bytecode: "6080604052...0008190033",
          initialBalance?, // Optional param - type: number
          adminKey?, // Optional param - type: string
          constructorParameters?: // Optional param - type: SmartContractFunctionParameter[]
          contractMemo?, // Optional param - type: string
          stakedNodeId?, // Optional param - type: number
          stakedAccountId?, // Optional param - type: string
          declineStakingReward?, // Optional param - type: boolean
          autoRenewPeriod?, // Optional param - type: number
          maxAutomaticTokenAssociations?, // Optional param - type: number
          /* 
            Uncomment the below line if you want to connect 
            to a non-metamask account
          */
          // ...externalAccountParams
        }
      }
    }
  })
}

• If you don't pass in adminKey,you will not be able modify the contract fields

What the API does

1. Retrieves the currently connected account the user has selected on Metamask. If it's the first time, a new snap account is created and the account info is saved in snap state.
2. Parses the arguments that were passed such as the gas, bytecode, adminKey, etc.

3. Calls the Hedera SDK Create Smart Contract API to create a new smart contract instance. This API uses ContractCreateFlow() API to create the file storing the bytecode and contract in a single step so you do not need to do anything other than compile your Solidity code and pass the bytecode to the API. The constructor will be executed using the given amount of gas, and any unspent gas will be refunded to the paying account.
4. Returns the transaction receipt as response

An example response:

{
    "currentAccount": {
        "metamaskEvmAddress": "0x0b3628d1b838993b5fceec8b2a26502e7a8e5241",
        "externalEvmAddress": "",
        "hederaAccountId": "0.0.3581604",
        "hederaEvmAddress": "0xca53f9c93d30e0b7212d67901e5a24fb090d542b",
        "publicKey": "0x0206022cea4c6dd6d2e7263b8802253971de922f5380661d97cba82dee66f57ad6",
        "balance": {
            "hbars": 104.67332072,
            "timestamp": "Thu, 25 Apr 2024 17:54:55 GMT",
            "tokens": {}
        },
        "network": "testnet",
        "mirrorNodeUrl": "https://testnet.mirrornode.hedera.com"
    },
    "receipt": {
        "status": "SUCCESS",
        "accountId": "",
        "fileId": "",
        "contractId": "0.0.4409710",
        "topicId": "",
        "tokenId": "",
        "scheduleId": "",
        "exchangeRate": {
            "hbars": 30000,
            "cents": 358240,
            "expirationTime": "Thu, 25 Apr 2024 19:00:00 GMT",
            "exchangeRateInCents": 11.941333333333333
        },
        "topicSequenceNumber": "0",
        "topicRunningHash": "",
        "totalSupply": "0",
        "scheduledTransactionId": "",
        "serials": [],
        "duplicates": [],
        "children": []
    }
}

Live Demo on CodePen

• Note: Visit https://pulse.tuum.tech/ to activate your hedera account before you interact with the demo
• If you're getting any errors with the live demo, make sure you go through the FAQs section to learn about what you may be missing. You need to install Metamask in your browser for the live demo to work.
• To ease the integration of Hedera Wallet Snap on an application, we have created a template web application that you can run locally and check out the code in its entirety to learn how you can integrate and interact with various APIs exposed by Hedera Wallet Snap. Check out the full source code at template application github repository.
• You can also check out the API reference to learn how each API works.