Question

I don’t really know how to put this question, but here we go.

So let’s assume I’m using ASIO from Boost libs to connect to a server using a TCP socket and write a certain message to it.

The message contains some user data and looks like this: 1 byte (packet ID), 4 bytes (integer), user null-terminated string and 6 zero bytes (reserved by the server but unused).

What would be the most convenient way to assemble such a message for use with ASIO’s boost::asio::buffer function?

I’m really confused at this point. Help greatly appreciated.

Answer 1

A. Define packet structures that can be serialized.

class ISerializable
{
public:
    virtual ~ISerializable(){}

    virtual void serialize(std::ostream& stream) = 0;
};

class LoginPacket : public ISerializable
{
public:
    // Constructor and access functions

    virtual void serialize(std::ostream& stream)
    {
        stream.write((const char*)&packetId, 1);
        stream.write((const char*)&accountId, 4);
        stream.write(username.c_str(), username.size() + 1);
        // Write the unused 6-bytes of zero
        int zero(0);
        stream.write((const char*)&zero, 4);
        stream.write((const char*)&zero, 2);
    }

private:
    unsigned char packetId;
    unsigned int32_t accountId;
    std::string username;
};

B. Now, to use this packet class do something like:

LoginPacket packet;
// Fill details for the packet
std::stringstream data;
packet.serialize(data);
// Send the data to the network
yourSocket.send(data.str().c_str(), data.str().size());