C++ TCP server Class Design

Question

I am developing TCP server in C++(win32/linux) which cater multiple client.The server is for Video Streaming.Client request video to server and Server get it from Gateway connected with camera. I am stuck up in the class Design.I found three classes by

1. Peer
2. Session and
3. ConnectionMgr.

So here ConnectionMgr is responsible for managing other Classes.

I wanted your feedback on this.

1. what info Peer and session need to have;
2. How Peer and session is related
3. what information needs to be modeled here.
4. how to do Session maintainer.
5. Managing multiple client will require Threads what information thoses may need.

Please give your feedback so that I can upgrade my design.

Answer 1

Looking at the problem space from scratch:

• there's some state associated with each client that connects - you seem to split this between Peer and Session and I see no real value in that if they're 1:1 - can omit such trivia from the high-level design stage.
  • "what info Peer and session need to have": socket descriptor is the only crucial thing, assuming you have only one camera and stream to all clients at the same pace (losing data when socket send() blocks/can't complete due to full buffer), otherwise, a buffer too...
• you have a ConnectionMgr, well - yes... it must listen and accept clients on the server socket, possibly launch a new thread per client or monitor the set of current client connections and dispatch events
• you'll need to make some decisions about the I/O and concurrency model (eg select/poll/non-blocking, async, blocking, single threaded, thread-per-client, thread-pool etc)
  • this will obviously affect your design: you should decide which - or which choices - you need to support...

To get a feel for this problem space, I suggest you create a very simple client/server program - probably using threads if you're familiar and comfortable with multithreading, otherwise you can hack upon the GCC libc TCP client/server examples for a select() based solution (http://www.gnu.org/s/libc/manual/html_node/Server-Example.html#Server-Example) or try boost::asio or ACE or whatever. To start, just get it working so you can telnet to the server and whatever you type in any connection is echoed out on all the connections. That should give you enough insight to start asking more concrete questions.

Answer 2

As @nabulke and @Jan Hudec stated in their comments, Boost.Asio is very good solution for your problem. Have a look at pretty simple example "Async TCP Echo Server" . It uses just 2 classes: server and session . No session_manager . Sessions are managed automatically by smart pointers, very convenient and simple approach.

Using Boost.Asio you can keep the network part simple (and almost optimal by efficiency using asynchronous processing). As a bonus, adding couple of code lines, you receive multithreaded server w/o headache (I would recommend this example: "An HTTP server using a single io_service and a thread pool calling io_service::run()." , just ignore HTTP stuff. pay attention to boost::asio::io_service::strand used in connection class)