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create-a-file.md

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Create a file

A transaction that creates a new file on a Hedera network. The file is referenced by its file ID which can be obtained from the receipt or record once the transaction reaches consensus on a Hedera network. 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().

{% hint style="info" %} The maximum file size is 1,024 kB. {% endhint %}

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

File Properties

Field Description
Key(s) Set the keys which must sign any transactions modifying this file (the owner(s) of the file). All keys must sign to modify the file's contents or keys. No key is required to sign for extending the expiration time (except the one for the operator account paying for the transaction). The network currently requires a file to have at least one key (or key list or threshold key) but this requirement may be lifted in the future.
Contents The contents of the file. The file contents can be recovered from requesting the FileContentsQuery. Note that the total size for a given transaction is limited to 6KiB (as of March 2020) by the network; if you exceed this you may receive a TRANSACTION_OVERSIZE error.
Expiration Time Set the instant at which this file will expire, after which its contents will no longer be available. Defaults to 1/4 of a Julian year from the instant was invoked.
Memo Short publicly visible memo about the file. No guarantee of uniqueness. (100 characters max)

Methods

Constructor Description
new FileCreateTransaction() Initializes the FileCreateTransaction object 
new FileCreateTransaction()

{% hint style="info" %} The default max transaction fee (1 hbar) is not enough to create a a file. Use setMaxTransactionFee()to change the default max transaction fee from 1 hbar to 2 hbars. {% endhint %}

{% tabs %} {% tab title="V2" %}

Method Type Requirement
setKeys(<keys>) Key Required
setContents(<contents>) String Optional
setContents(<bytes>) bytes [ ] Optional
setExpirationTime(<expirationTime>) Instant Optional
setFileMemo(<memo>) String Optional

{% code title="Java" %}

//Create the transaction
FileCreateTransaction transaction = new FileCreateTransaction()
    .setKeys(fileKey) 
    .setContents(fileContents);
        
//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(fileKey).execute(client);

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

//Get the file ID
FileId newFileId = receipt.fileId;

System.out.println("The new file ID is: " + newFileId);

//v2.0.0

{% endcode %}

{% code title="JavaScript" %}

//Create the transaction
const transaction = await new FileCreateTransaction()
    .setKeys([filePublicKey]) //A different key then the client operator key
    .setContents("the file contents")
    .setMaxTransactionFee(new Hbar(2))
    .freezeWith(client);

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

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

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

//Get the file ID
const newFileId = receipt.fileId;

console.log("The new file ID is: " + newFileId);

//v2.0.7

{% endcode %}

{% code title="Go" %}

//Create the transaction
transaction := hedera.NewFileCreateTransaction().
		SetKeys(filePublicKey).
		SetContents([]byte("Hello, World"))

//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
txResponse, 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 file ID
newFileId := *receipt.FileID

fmt.Printf("The new file ID is %v\n", newFileId)
//v2.0.0

{% endcode %} {% endtab %}

{% tab title="V1" %}

Method Type Description Requirement
addKey(<key>) ​PublicKey​ The public key of the owner of the file Required
setContents(<contents>) bytes[] The file contents in byte representation Optional
setContents(<contents>) String The file contents in string representation Optional
setExpirationTime(<expiration>) Instant The time at which this file should expire (unless FileUpdateTransaction is used before then to extend its life) Optional

{% code title="Java" %}

//Create the transaction
FileCreateTransaction transaction = new FileCreateTransaction()
    .addkey(fileKey) 
    .setContents(fileContents);
        
//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
TransactionId txId = modifyMaxTransactionFee.build(client).sign(fileKey).execute(client);

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

//Get the file ID
FileId newFileId = receipt.getFileId();

System.out.println("The new file ID is: " + newFileId);

//v1.3.2

{% endcode %}

{% code title="JavaScript" %}

//Create the transaction
const transaction = new FileCreateTransaction()
    .addkey(fileKey) 
    .setContents(fileContents);
        
//Change the default max transaction fee to 2 hbars
const 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
const txId = await modifyMaxTransactionFee.build(client).sign(fileKey).execute(client);

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

//Get the file ID
const newFileId = receipt.getFileId();

console.log("The new file ID is: " + newFileId);

//v1.4.4

{% endcode %} {% endtab %} {% endtabs %}

Get transaction values

{% tabs %} {% tab title="V2" %}

Method Type Requirement
getKeys() Key Optional
getContents() ByteString Optional
getExpirationTime() Instant Optional
getFileMemo() String Optional

{% code title="Java" %}

//Create the transaction
FileCreateTransaction transaction = new FileCreateTransaction()
    .setKeys(key)
    .setContents(fileContents);
        
//Get the file contents
ByteString getContents = transaction.getContents();

{% endcode %}

{% code title="JavaScript" %}

//Create the transaction
const transaction = new FileCreateTransaction()
    .setKeys(key)
    .setContents(fileContents);
        
//Get the file contents
const getContents = transaction.getContents();

{% endcode %}

{% code title="Go" %}

//Create the transaction
transaction := hedera.NewFileCreateTransaction().
		SetKeys(filePublicKey).
		SetContents([]byte("Hello, World"))

//Get the file contents
getContents := transaction.GetContents()

{% endcode %} {% endtab %}

{% tab title="V1" %}

Method Type Description Requirement
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)

{% code title="Java" %}



{% endcode %}


{% code title="JavaScript" %}




{% endcode %}


{% code title="Go" %}




{% endcode %}
{% endtab %}
{% endtabs %}