CODEWITHSUNDEEP
c#socketsudptimeout
Jake Smokie
Jake Smokie

Reputation: 115

Socket.Avaliable loss C#

I wrote this method using UDP socket with ReceiveTimeout = 1000. And sometimes it loses second packet:

private static byte[] ReceivePlainData(Socket socket) {
    var recievedData = new List<byte>();
    var buffer = new byte[1024];

    do {
        int recievedAmount;

        while (true) {
            try {
                recievedAmount = socket.Receive(buffer);
            }
            catch (SocketException) {
                continue;
            }

            break;
        }

        recievedData.AddRange(buffer.Take(recievedAmount));
    } while (socket.Available > 0);

    return recievedData.ToArray();
}

Socket initialization:

using (var socket = new Socket(SocketType.Dgram, ProtocolType.Udp) {
    ReceiveTimeout = 1000
})

What do i need to change to make this method work correctly?

Upvotes: 0

Views: 468

Answers (1)

jspcal
jspcal

Reputation: 51904

Socket.Available only tells you if data has been received and available for immediate reading. It doesn't tell you if the stream is complete or not. The sender may still be in the process of generating or transmitting more data. If you intend to consume the entire response and are relying on the socket to be closed by the sender when there is no more data, continue reading from the socket until the number of bytes returned is 0 (indicating the socket was closed normally) or an exception occurs (indicating abnormal termination).

MemoryStream stream = new MemoryStream();
int received;
var buffer = new byte[8096];

do {
    received = socket.Receive(buffer);
    stream.Write(buffer, 0, received);
} while (received > 0);

// Use the stream
// byte[] bytes = stream.ToArray();

Set your socket's ReceiveTimeout to the maximum amount of time you're willing to wait between bytes before aborting.

Upvotes: 1

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