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https://github.com/uliwitness/eleven

A simple, modular, BSD-socket-based C++ chat server and client. Intended as a foundation for embedding in other apps and building actual chat systems on top of, or network communication for other client/server systems.
https://github.com/uliwitness/eleven

experiment interconnect-game work-in-progress

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A simple, modular, BSD-socket-based C++ chat server and client. Intended as a foundation for embedding in other apps and building actual chat systems on top of, or network communication for other client/server systems.

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README 

          
A small, modular, C++, BSD-socket-based chat client and server, intended for use in

projects that want to embed chat or chat-like functionality.



Warning

-------



If you want to use this in production, you *must* obtain your own certificates (e.g.

by buying them from your web hoster). The included certificates are up for everyone

on Github and can therefore be used by anyone to spoof messages. They are merely

included as a convenience for those trying out the code.



For deployment, you should set up a settings folder containing your certificates and

accounts and pass its path as the first parameter to the server/client.



Usage

-----



The app includes a simple test "client" that you can modify to try things out. By

default it will simply perform a few commands and display the replies returned by

those.



The example server is reasonably full-featured and implements a protocol vaguely

reminiscent of IRC. There is a "/login admin eleven" command to log you in

(the example is the default user name and password in a fresh build). A "/bye" command

to end your session. A "/join myChannel" command for creating and listening to a

channel. A "/leave myChannel" command to stop listening to a channel, commands to

create new users, ban users from a channel or even from just logging in, etc.



See the comments on each line that registers a handler in the example server's

main.cpp file for all commands currently supported.



Installation

------------



For TLS support (i.e. so user passwords don't cross the line in plain text), you need

to build LibreSSL's libtls. The project has a "libressl" target that does that for you,

but you may need to install automake, autoconf and libtool, e.g. using Homebrew 



	brew install autoconf automake libtool



as that is what the libTLS build scripts use.



Command handlers

----------------



The chat server class is stupid by default and does nothing. To make it do something, you

give it C++ lambdas (aka "blocks" or "handlers"). Each line received has its first word

extracted (everything up to the first space, tab or line break), and matched against the

strings for which handlers have been registered. If none of these matches, it looks for a

handler registered for "*" and calls that.



These handlers get handed a session object with which they can send a reply, and

the entire line (including the first word) that the client sent. They can now

decide how to react.



The same principle applies to the client.



Types of users

--------------



There are three kinds of users. "Normal" users can simply join/create channels and chat.

"Moderator" users can kick users from channels, block and retire users from logging in,

or delete a user, as long as the other user is a "Normal" user. "Owner" users can create

new accounts on the server, and designate other accounts as moderators or owners. Owners

can also do all the things moderators can.



When you build the example server, the Xcode project will copy a default accounts.txt

file next to the application that defines one user named "admin" with password "eleven".

This user is an "Owner" and can be used to create other users etc.



Format of messages

------------------



While messages sent from server to client can really have any format you wish (they can

even consist of binary data), the defaults have a strict format that will make it easier

to parse for clients and display them in a graphical fashion or localize them. All replies

from the server start with a reply code prefixed with a slash, which is the first word

of the first line. If this code starts with an exclamation mark right after the slash,

it indicates an error occurred (e.g. a message may start with "/!not_logged_in" for "you are

not logged in").



Then, messages usually contain one or more words (separated by spaces) indicating additional

metadata like the channel on which a message was sent, or the user name of the user that

originally sent the message. The rest of the line is usually the actual message sent, if any.



So if you were using Eleven to implement, say, the communications mechanism in an MMORPG,

the game the user downloads would be a client, and could choose to display all messages that

start with "/!" in modal error alert panel. It could display messages that start with

"/note" as text subtitles at the top of the game screen, and messages that start

with "/joined_channel" could be meant to be the area in which the user is now playing.

Messages that start with "/message" (Actual text a user types) can even be shown as

speech balloons over the corresponding character's head, as they include channel and

user name.



The server can even ask on behalf of the player to have the player join or leave a chatroom,

e.g. when the player moves from one map to the next, so that chat will show up in the current

room for all other players who are there with her.



License

-------



    Copyright 2014 by Uli Kusterer.



    This software is provided 'as-is', without any express or implied

    warranty. In no event will the authors be held liable for any damages

    arising from the use of this software.



    Permission is granted to anyone to use this software for any purpose,

    including commercial applications, and to alter it and redistribute it

    freely, subject to the following restrictions:



    1. The origin of this software must not be misrepresented; you must not

    claim that you wrote the original software. If you use this software

    in a product, an acknowledgment in the product documentation would be

    appreciated but is not required.



    2. Altered source versions must be plainly marked as such, and must not be

    misrepresented as being the original software.



    3. This notice may not be removed or altered from any source

    distribution.