Swift
Swift
Send a 4-byte Length Prefix over a Socket
See more Socket/SSL/TLS Examples
Demonstrates Socket.SendCount, which sends a four-byte length prefix in network byte order. This is typically used to tell the peer how many bytes follow.
Background. A length-prefixed framing scheme sends the byte count of a message before the message body, so the receiver knows exactly how many bytes to read with a counted receive.
Chilkat Swift Downloads
func chilkatTest() {
var success: Bool = false
let socket = CkoSocket()!
// Connect to the server using TLS.
var bTls: Bool = true
var maxWaitMs: Int = 5000
success = socket.connect(hostname: "example.com", port: 5000, ssl: bTls, maxWaitMs: maxWaitMs)
if success == false {
print("\(socket.lastErrorText!)")
return
}
// Send a four-byte length prefix in network byte order. A common framing pattern is to send the
// number of bytes in a message before the message itself, so the peer knows exactly how many bytes
// to read.
var messageLength: Int = 512
success = socket.sendCount(byteCount: messageLength)
if success == false {
print("\(socket.lastErrorText!)")
return
}
print("Length prefix sent.")
}