Need help to build network class

[weeb0]

Hi everyone,

I'm currently working a Network class. For the moment, I have a class containing the following functions :

class cNetwork
{
	cnetwork();
	cnetwork(int port);
	~cnetwork();
	void send_to(char *buffer,int length);
	int receive_from(char *buf,int buf_size);
	void bind_to(void);
	void wait_connection(void);
};

I think it should be a good thing to separate the server functions of the generic ones ("send_to"/"receive_from") and I should add a "connect_to" one.

When I have a server, if I accept a connection, a new socket number is created, so I need to have 2 socket variable in the class. It's not needed when I have to use a client connection. So, I would like to build the following inheritance of class:

parent : cNetwork (containing the socket and receive_from / send_to functions)

childrens :
cNetwork_server (containing the bind, accept...)
cNetwork_client (containing the connect and other usefull functions to search the dns etc...)


This mean the cNetwork_server class need to access to the socket variable of the parent class. Is this a good practice to use ?
Can you see another way to do this ? Any advice ???

Here the code of the class to be sure everybody can understand what I would like to do:

class cNetwork
{
public:
    cNetwork();
    ~cNetwork();
    void send_to(char *buffer,int size);
    int receive_from(char *buffer,int size);
protected:
    int socket;
};

class cNetwork_server : cNetwork
{
    /* I must use the variable socket of the parent class withing the functions of this class */
    cNetwork_server();
    ~cNetwork_server();
    void bind_to();
    void wait_for_connection();
};

class cNetwork_client : cNetwork
{
    /* I must use the variable socket of the parent class withing the functions of this class */
     cNetwork_client();
     ~cNetwork_client();
     void connect_to();
};

thank you for your precious help!

 

[cpjust]

I haven't done much network programming, but the network classes I've seen usually had a CSocket base class containing all the low level socket functions. Then they usually had CInputSocket & COutputSocket or CClientSocket & CServerSocket which derived from or contained the CSocket base class.

You might also provide a server constructor that takes the max number of connections. Then it can create a thread pool with that many server theads to accept the connections.

Your void connect_to() function should take a parameter for the IP address or DNS name and the port of the machine to connect to. You should also return a bool indicating if it connected properly or if it failed.

You should also consider a way to switch from TCP to UDP...

I'd have the send/receive functions like this:

int Send( const void* pData, int dataSize, unsigned int flags = 0 );
int Receive( void* pBuffer, int bufSize, unsigned int flags = 0 );

 

[weeb0]

OK!

but, is it a good practice to access the variable of the parent ? I know it's possible to do it, but we can use global variable and this is a very bad habit!

Thank you.

 

[cpjust]

If you're only reading the base class variable, there usually isn't much of a problem (as long as you're sure it's initialized to a proper value). If you're writing to it, then it might be better to handle that in the base class. It also depends if your application is multi-threaded or not.
Personally, I tend to access base class variables only if it's absolutely necessary, which in this case it probably is.