create-a-file.md

Create a file

FileCreateTransaction() creates a new file. The file is referenced by its file ID which can be obtained from the receipt or record of the transaction. The file does not have a file name. If the file is too big to create with a single FileCreateTransaction(), the file can be appended with the remaining content multiple times using the FileAppendTransaction() constructor.

Constructor	Description
FileCreateTransaction	Initializes the FileCreateTransaction object

new FileCreateTransaction()

Basic

Method	Type	Description
addKey(<key>)	Ed25519PublicKey	The public key of the owner of the file
setContents(<contents>)	bytes[]	The file contents
setExpirationTime(<expiration>)	Instant	The time at which this file should expire (unless FileUpdateTransaction is used before then to extend its life)

Example

{% tabs %} {% tab title="Java" %}

// `Client.forMainnet()` is provided for connecting to Hedera mainnet
Client client = Client.forTestnet();

// Defaults the operator account ID and key such that all generated transactions will be paid for
// by this account and be signed by this key
client.setOperator(OPERATOR_ID, OPERATOR_KEY);

// The file is required to be a byte array,
// you can easily use the bytes of a file instead.
byte[] fileContents = "Hedera hashgraph is great!".getBytes();

TransactionId txId = new FileCreateTransaction()
    // Use the same key as the operator to "own" this file
    .addKey(OPERATOR_KEY.publicKey)
    .setContents(fileContents)
    // The default max fee of 1 HBAR is not enough to make a file ( starts around 1.1 HBAR )
    .setMaxTransactionFee(200_000_000) // 2 HBAR
    .execute(client);

TransactionReceipt receipt = txId.getReceipt(client);
FileId newFileId = receipt.getFileId();

System.out.println("file: " + newFileId);

{% endtab %}

{% tab title="JavaScript" %}

const { Client, FileCreateTransaction, Ed25519PrivateKey, Hbar } = require("@hashgraph/sdk");
require("dotenv").config();

async function main() {
  
  const operatorAccount = process.env.OPERATOR_ID;
  const operatorPrivateKey = Ed25519PrivateKey.fromString(process.env.OPERATOR_KEY);
  const operatorPublicKey = operatorPrivateKey.publicKey;

  if (operatorPrivateKey == null || operatorAccount == null) {
    throw new Error(
      "environment variables OPERATOR_KEY and OPERATOR_ID must be present"
    );
  }

  const client = Client.forTestnet()
  client.setOperator(operatorAccount, operatorPrivateKey);

  const transactionId = await new FileCreateTransaction()
    .setContents("Hello, Hedera's file service!")
    .addKey(operatorPublicKey) // Defines the "admin" of this file
    .setMaxTransactionFee(new Hbar(15))
    .execute(client);

  const receipt = await transactionId.getReceipt(client);  
  console.log("new file id = ", receipt.getFileId());
}

main();

{% endtab %} {% endtabs %}