Append to a file

A transaction that appends new file content to the end of an existing file. The contents of the file can be viewed by submitting a FileContentsQuery request.

Transaction Signing Requirements

• The key on the file is required to sign the transaction if different than the client operator account key

Transaction Fees

• Please see the transaction and query fees table for base transaction fee

• Please use the Hedera fee estimator to estimate your transaction fee cost

Constructor	Description
FileAppendTransaction()	Initializes the FileAppendTransaction object

new FileAppendTransaction()

The default max transaction fee (1 hbar) is not enough to create a file. Use setMaxTransactionFee()to change the default max transaction fee from 1 hbar to 2 hbars. The default chunk size is 2,048 bytes.

Methods

Method	Type	Description	Requirement
setFileId(<fileId>)	FileId	The ID of the file to append	Required
setContents(<text>)	String	The content in String format	Optional
setContents(<content>)	byte [ ]	The content in byte format	Optional
setChunkSize(<chunkSize>)	int	The chunk size	Optional
setMaxChunkSize(<maxChunks>)	int	The max chunk size	Optional

Java

//Create the transaction
FileAppendTransaction transaction = new FileAppendTransaction()
    .setFileId(newFileId)
    .setContents("The appended contents");

//Change the default max transaction fee to 2 hbars
FileCreateTransaction modifyMaxTransactionFee = transaction.setMaxTransactionFee(new Hbar(2)); 

//Prepare transaction for signing, sign with the key on the file, sign with the client operator key and submit to a Hedera network
TransactionResponse txResponse = modifyMaxTransactionFee.freezeWith(client).sign(key).execute(client);

//Request the receipt
TransactionReceipt receipt = txResponse.getReceipt(client);

//Get the transaction consensus status
Status transactionStatus = receipt.status;

System.out.println("The transaction consensus status is " +transactionStatus);

//v2.0.0

JavaScript

//Create the transaction
const transaction = await new FileAppendTransaction()
    .setFileId(newFileId)
    .setContents("The appended contents")
    .setMaxTransactionFee(new Hbar(2))
    .freezeWith(client);

//Sign with the file private key
const signTx = await transaction.sign(fileKey);

//Sign with the client operator key and submit to a Hedera network
const txResponse = await signTx.execute(client);

//Request the receipt
const receipt = await txResponse.getReceipt(client);

//Get the transaction consensus status
const transactionStatus = receipt.status;

console.log("The transaction consensus status is " +transactionStatus);

//v2.0.5

Go

//Create the transaction
transaction2 := hedera.NewFileAppendTransaction().
        SetFileID(newFileId).
        SetContents([]byte("The appended contents"))

//Change the default max transaction fee to 2 hbars
modifyMaxTransactionFee := transaction.SetMaxTransactionFee(hedera.HbarFrom(2, hedera.HbarUnits.Hbar))

//Prepare transaction for signing, 
freezeTransaction, err := modifyMaxTransactionFee.FreezeWith(client)
if err != nil {
        panic(err)
}

//Sign with the key on the file, sign with the client operator key and submit to a Hedera network
txResponse2 err := freezeTransaction.Sign(fileKey).Execute(client)
if err != nil {
        panic(err)
}

//Request the receipt
receipt, err := txResponse.GetReceipt(client)
if err != nil {
        panic(err)
}

//Get the transaction consensus status
transactionStatus := receipt.Status

fmt.Println("The transaction consensus status is ", transactionStatus)

//v2.0.0

Get transaction values

Method	Type	Description	Requirement
getFileId()	FileId	The file ID in the transaction	Optional
getContents()	String	The content in the transaction	Optional

Java

//Create the transaction
FileAppendTransaction transaction = new FileAppendTransaction()
    .setFileId(newFileId)
    .setContents("The appended contents");

//Get the contents
ByteString getContents = transaction.getContents();

//v2.0.0

JavaScript

//Create the transaction
const transaction = new FileAppendTransaction()
    .setFileId(newFileId)
    .setContents("The appended contents");

//Get the contents
const getContents = transaction.getContents();

Go

//Create the transaction
transaction2 := hedera.NewFileAppendTransaction().
    SetFileID(newFileId).
        SetContents([]byte("The appended contents"))

//Get the contents
getContents2 := transaction2.GetContents()

//v2.0.0