(Go) 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 Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

    // 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.
    bdToSend := chilkat.NewBinData()
    success := bdToSend.LoadFile("somePath/someFile.dat")
    // Assume success for the example...

    sndSock := chilkat.NewSocket()
    bUseTls := true
    port := 5555
    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.
    numBytes := bdToSend.NumBytes()
    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 {
        fmt.Println(sndSock.LastErrorText())
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        return
    }

    // Did the receiver get the correct number of bytes?
    if sndSock.ReceivedInt() != numBytes {
        fmt.Println("The receiver did not acknowledge with the correct number of bytes.")
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        return
    }

    fmt.Println("File sent!")

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

    listenSock := chilkat.NewSocket()

    success = listenSock.BindAndListen(5555,25)
    if success != true {
        fmt.Println(listenSock.LastErrorText())
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        listenSock.DisposeSocket()
        return
    }

    // Get the next incoming connection
    // Wait a maximum of 20 seconds (20000 millisec)
    // rcvSock is a Socket
    rcvSock := listenSock.AcceptNextConnection(20000)
    if listenSock.LastMethodSuccess() == false {
        fmt.Println(listenSock.LastErrorText())
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        listenSock.DisposeSocket()
        return
    }

    // The sender will first send the big-endian integer for the number of bytes
    // that are forthcoming..
    success = rcvSock.ReceiveInt32(bBigEndian)
    if success != true {
        fmt.Println(rcvSock.LastErrorText())
        rcvSock.DisposeSocket()
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        listenSock.DisposeSocket()
        return
    }

    numBytesComing := rcvSock.ReceivedInt()

    // Receive that many bytes..
    bdReceived := chilkat.NewBinData()
    success = rcvSock.ReceiveBdN(numBytesComing,bdReceived)
    if success != true {
        fmt.Println(rcvSock.LastErrorText())
        rcvSock.DisposeSocket()
        bdToSend.DisposeBinData()
        sndSock.DisposeSocket()
        listenSock.DisposeSocket()
        bdReceived.DisposeBinData()
        return
    }

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

    // Close the connection.
    maxWaitMs := 20
    rcvSock.Close(maxWaitMs)
    rcvSock.DisposeSocket()

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

    fmt.Println("File received!")

    bdToSend.DisposeBinData()
    sndSock.DisposeSocket()
    listenSock.DisposeSocket()
    bdReceived.DisposeBinData()