> For the complete documentation index, see [llms.txt](https://abc.bharatblockchain.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://abc.bharatblockchain.io/hedera/tutorials/smartcontract-service/get-seal.md).

# Get Seal

### Summary:

The script queries a smart contract deployed on the Hedera network to retrieve information about a seal using a specific hash. It showcases how to send queries to the smart contract and process the query results.

### 1. Imports and Environment Setup:

```javascript
const {
    Client,
    ContractFunctionParameters,
    ContractCallQuery,
    Hbar, PrivateKey
} = require("@hashgraph/sdk");
require('dotenv').config({ path: 'SmartContract_Service/.env' });
```

* It imports necessary modules from the Hedera JavaScript SDK (`@hashgraph/sdk`) and the `dotenv` module to load environment variables from a `.env` file located in the `SmartContract_Service` directory.

### 2. Environment Variables Retrieval and Validation:

```javascript
const myAccountId = process.env.MY_ACCOUNT_ID;
const myPrivateKey = PrivateKey.fromString(process.env.MY_PRIVATE_KEY);
const contractId = process.env.CONTRACT_ID;
const hash = process.env.HASH;

if (myAccountId == null || myPrivateKey == null) {
    throw new Error("Environment variables myAccountId and myPrivateKey must be present");
}
```

* It retrieves the account ID, private key, contract ID, and hash from the `.env` file.
* It checks whether these variables are present; otherwise, it throws an error.

### 3. Client Setup:

```javascript
const client = Client.forTestnet();
client.setOperator(myAccountId, myPrivateKey);
```

* It creates a client instance for the Hedera testnet and sets the operator account using the user's account ID and private key.

### 4. Main Function:

```javascript
async function main() {
    //Query the contract for the contract message
    const contractCallQuery = new ContractCallQuery()
        .setContractId(contractId)
        .setGas(100000)
        .setFunction("getSeal", new ContractFunctionParameters().addString(hash))
        .setQueryPayment(new Hbar(10));

    const contractQuerySubmit = await contractCallQuery.execute(client);
    const sealedBlock = contractQuerySubmit.getUint256(0);
    const revokedBlock = contractQuerySubmit.getUint256(1);
    const sealOwner = contractQuerySubmit.getAddress(2);

    console.log("The seal was created by the address " + sealOwner + " on block #" + sealedBlock + " and got revoked at block #" +revokedBlock);

    process.exit();
}
```

* It defines the `main()` function, which is the entry point of the script.
* It creates a query to call the `getSeal` function of the smart contract with the provided hash parameter.
* The query is submitted to the Hedera network, and the result is retrieved.
* The sealed block, revoked block, and seal owner are extracted from the query result and logged to the console.

### 5. Execution:

```javascript
main();
```

* This line calls the `main()` function to start the execution of the script.