(C# UWP/WinRT) 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 Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

// 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.
Chilkat.BinData bdToSend = new Chilkat.BinData();
bool success = bdToSend.LoadFile("somePath/someFile.dat");
// Assume success for the example...

Chilkat.Socket sndSock = new Chilkat.Socket();
bool bUseTls = true;
int port = 5555;
int maxWaitMs = 5000;
success = await sndSock.ConnectAsync("some_domain_or_ip.com",port,bUseTls,maxWaitMs);
// Assume success for the example...

// Tell the receiver how many bytes are coming.
int numBytes = bdToSend.NumBytes;
bool bBigEndian = true;
success = await sndSock.SendInt32Async(numBytes,bBigEndian);

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

// Get an acknowledgement.
success = await sndSock.ReceiveInt32Async(bBigEndian);
if (success != true) {
    Debug.WriteLine(sndSock.LastErrorText);
    return;
}

// Did the receiver get the correct number of bytes?
if (sndSock.ReceivedInt != numBytes) {
    Debug.WriteLine("The receiver did not acknowledge with the correct number of bytes.");
    return;
}

Debug.WriteLine("File sent!");

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

Chilkat.Socket listenSock = new Chilkat.Socket();

success = await listenSock.BindAndListenAsync(5555,25);
if (success != true) {
    Debug.WriteLine(listenSock.LastErrorText);
    return;
}

// Get the next incoming connection
// Wait a maximum of 20 seconds (20000 millisec)
Chilkat.Socket rcvSock = null;
rcvSock = await listenSock.AcceptNextConnectionAsync(20000);
if (listenSock.LastMethodSuccess == false) {
    Debug.WriteLine(listenSock.LastErrorText);
    return;
}

// The sender will first send the big-endian integer for the number of bytes
// that are forthcoming..
success = await rcvSock.ReceiveInt32Async(bBigEndian);
if (success != true) {
    Debug.WriteLine(rcvSock.LastErrorText);

    return;
}

int numBytesComing = rcvSock.ReceivedInt;

// Receive that many bytes..
Chilkat.BinData bdReceived = new Chilkat.BinData();
success = await rcvSock.ReceiveBdNAsync(numBytesComing,bdReceived);
if (success != true) {
    Debug.WriteLine(rcvSock.LastErrorText);

    return;
}

// Acknowledge the sender by sending back the number of bytes we received.
success = await rcvSock.SendInt32Async(bdReceived.NumBytes,bBigEndian);

// Close the connection.
int maxWaitMs = 20;
await rcvSock.CloseAsync(maxWaitMs);

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

Debug.WriteLine("File received!");