(Xojo Plugin) Transfer a File using Sockets (TLS or non-TLS)

Demonstrates how to two programs, one a socket writer and the other a socket reader, can transfer a file. The connection can be TLS or a regular non-encrypted TCP connection.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// On the sending side, we'll load the file into a BinData object and send.
// On the receiving side, we'll read from the socket connection into a BinData, and save to a file.
// This example assumes the file is not crazy-large, and that the entire contents
// can fit into memory.  
// (If the file is too large for memory, there are other ways to send. It just involves streaming or 
// sending the file chunk-by-chunk..)

// This section of code is for the sender.
Dim bdToSend As New Chilkat.BinData
Dim success As Boolean
success = bdToSend.LoadFile("somePath/someFile.dat")
// Assume success for the example...

Dim sndSock As New Chilkat.Socket
Dim bUseTls As Boolean
bUseTls = True
Dim port As Int32
port = 5555
Dim maxWaitMs As Int32
maxWaitMs = 5000
success = sndSock.Connect("some_domain_or_ip.com",port,bUseTls,maxWaitMs)
// Assume success for the example...

// Tell the receiver how many bytes are coming.
Dim numBytes As Int32
numBytes = bdToSend.NumBytes
Dim bBigEndian As Boolean
bBigEndian = True
success = sndSock.SendInt32(numBytes,bBigEndian)

// Send the file data (sends the entire contents of bdToSend).
success = sndSock.SendBd(bdToSend,0,0)

// Get an acknowledgement.
success = sndSock.ReceiveInt32(bBigEndian)
If (success <> True) Then
    System.DebugLog(sndSock.LastErrorText)
    Return
End If

// Did the receiver get the correct number of bytes?
If (sndSock.ReceivedInt <> numBytes) Then
    System.DebugLog("The receiver did not acknowledge with the correct number of bytes.")
    Return
End If

System.DebugLog("File sent!")

// ------------------------------------------------------------------------------------
// The code below is for the receiving side (running on some other computer..)

Dim listenSock As New Chilkat.Socket

success = listenSock.BindAndListen(5555,25)
If (success <> True) Then
    System.DebugLog(listenSock.LastErrorText)
    Return
End If

// Get the next incoming connection
// Wait a maximum of 20 seconds (20000 millisec)
Dim rcvSock As Chilkat.Socket
rcvSock = listenSock.AcceptNextConnection(20000)
If (listenSock.LastMethodSuccess = False) Then
    System.DebugLog(listenSock.LastErrorText)
    Return
End If

// The sender will first send the big-endian integer for the number of bytes
// that are forthcoming..
success = rcvSock.ReceiveInt32(bBigEndian)
If (success <> True) Then
    System.DebugLog(rcvSock.LastErrorText)

    Return
End If

Dim numBytesComing As Int32
numBytesComing = rcvSock.ReceivedInt

// Receive that many bytes..
Dim bdReceived As New Chilkat.BinData
success = rcvSock.ReceiveBdN(numBytesComing,bdReceived)
If (success <> True) Then
    System.DebugLog(rcvSock.LastErrorText)

    Return
End If

// Acknowledge the sender by sending back the number of bytes we received.
success = rcvSock.SendInt32(bdReceived.NumBytes,bBigEndian)

// Close the connection.
Dim maxWaitMs As Int32
maxWaitMs = 20
success = rcvSock.Close(maxWaitMs)

// Save the received data to a file.
success = bdReceived.WriteFile("somePath/someFile.dat")
// Assume success for the example...

System.DebugLog("File received!")