fileHeader (12)

The fileHeader message initiates a file transfer by sending metadata about the file to the recipient. This allows the recipient's client to display a prompt to the user, asking them if they wish to accept or decline the incoming file.

Core Data Types

• string: A standard UTF-8 encoded string, prefixed with its length.
• IxiVarUInt: See IxiVarInt Encoding.

Payload Structure

The payload is a serialized object containing all the necessary information for the recipient to identify the file transfer.

Field	Data Type	Min	Max	Description
uid	string	*	*	A unique identifier for this specific file transfer session.
fileName	string	1	*	The original name of the file, including its extension.
fileSize	IxiVarUInt	1	*	The total size of the file in bytes.

Behavioral Notes

• Sending: A user initiates a file transfer by selecting a file. Their client generates a unique uid, constructs the fileHeader payload with the file's metadata, and sends it to the intended recipient.
• Receiving: Upon receiving a fileHeader, the recipient's client should display a notification to the user showing the fileName and fileSize and asking for confirmation to download. The client stores the uid to manage the transfer session.
• User Action: If the user accepts the transfer, their client responds with an acceptFile message, including the uid from this header. If they decline, no response is sent.