C# 套接字接收 : Taking in data until buffer is full dilemma

Question

这是我遇到问题的代码:

// read the file in chunks of 5KB
var buffer = new byte[1024*5];
int bytesRead = 0;
do
{
    bytesRead = host.Receive(buffer, buffer.Length, 0);
    output.Write(buffer, 0, bytesRead);
}
while (bytesRead == buffer.Length);

所以这是我的问题:只要缓冲区已满，我就想读入数据。但是，即使有更多数据，发送时也不能保证缓冲区被填满。这会导致 Receive 过早退出。如果我将 while 条件更改为 bytesRead > 0然后它到达数据和接收 block 的末尾，直到有更多数据可用(它不会)。我该如何解决这个问题？

Answer 1

我认为您需要考虑协议(protocol)的工作原理并制定更强大的解决方案。要么你去阻塞，然后你要么等到你没有更多的数据要读取，然后做其他事情，当你知道你有更多的数据要读取时再次读取。

或者你添加线程并有一个单独的线程，它只是读取然后它是否阻塞并不重要，因为它将在一个单独的线程上。

另一种可能更简单的解决方案是使用异步读取。

您可以在此处阅读更多信息:https://msdn.microsoft.com/en-us/library/bbx2eya8(v=vs.110).aspx

上面网站的一个简单示例是从阅读开始:

private static void Receive(Socket client) {
    try {
        // Create the state object.
        StateObject state = new StateObject();
        state.workSocket = client;

        // Begin receiving the data from the remote device.
        client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
            new AsyncCallback(ReceiveCallback), state);
    } catch (Exception e) {
        Console.WriteLine(e.ToString());
    }
}

然后当有数据需要处理时，你会得到一个回调到 ReceiveCallback:

private static void ReceiveCallback( IAsyncResult ar ) {
    try {
        // Retrieve the state object and the client socket 
        // from the asynchronous state object.
        StateObject state = (StateObject) ar.AsyncState;
        Socket client = state.workSocket;
        // Read data from the remote device.
        int bytesRead = client.EndReceive(ar);
        if (bytesRead > 0) {
            // There might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead));
                //  Get the rest of the data.
            client.BeginReceive(state.buffer,0,StateObject.BufferSize,0,
                new AsyncCallback(ReceiveCallback), state);
        } else {
            // All the data has arrived; put it in response.
            if (state.sb.Length > 1) {
                response = state.sb.ToString();
            }
            // Signal that all bytes have been received.
            receiveDone.Set();
        }
    } catch (Exception e) {
        Console.WriteLine(e.ToString());
    }
}

如果不是我们需要更多地了解您使用的协议(protocol)以及您是否出于某种原因需要阻止读取，我希望这可以工作，以便我们可以提供更具体的信息和帮助。