This program defines a template for a multi-user interface with a graphics display, chat server, and system commands. Once a host starts the interface, clients can connect to the server and chat with each other, and type system commands. System commands are passed to the host, and can be customized to interact with the graphics display or instruct the host process to perform any other computation. They are evaluated by the host process/machine, not by the process/machine that runs the client. The host process defines permission levels by username (so username doubles as a password), so system commands can be defined to have restricted access users with certain permission levels.
The graphics display currently runs only on the host process, so if you are connected from a different machine you cannot see the graphics display, only the chat server and the display server. This will be changed in future versions.
To start the interface, run:
python main.py
This will start an instance of the AiInterface class. This class in turn starts a server and a graphics display which can communicate with each other and with clients connected to the server. The graphics display runs on the main thread, and the server runs on a separate thread. The server and graphics display are fields of the AiInterface. AiInterface has internal variables that can be updated based on system commands from the users. Some examples are included, but in general you can customize it to enable any system commands you want, and any permissions you want so that different users have access to different commands. To connect to the server as a chat client:
python main.py -cclient
A chat client can type messages to the chat room. AiInterface has a 'while True' loop (the method 'command_loop') which runs on its own thread and constantly checks the server's todo queue. If a message written by a client starts with a word which appears in the list of known system commands, it will be added to the server's todo queue, and the command loop will pop it out of the queue. After a command was popped out of the server it is evaluated by the AiInterface's eval_cmd method, which displays the output to all connected display clients. Display clients are there simply to show the full output of system commands, which enables the server to stay clean for chatting. A short feedback message will be displayed to the chat clients when a command is executed. System output is global, so all display clients are the same. To connect for display:
python main.py -dclient
The parts of this program were written with the intention of being customized for many different purposes. Many parts of this program are templates, and they were accompanied by examples and explanations how to modify them for other purposes. To add system commands, add them to the CMD_TO_HELP constant in constants.py, which maps command names to their help documentation strings. The server will now recognize these commands as valid system commands.
To define what a command does, go to AiInterface.cmd_loop and create an if-clause that recognizes this commands and decides what it does. Commands can print any output to display clients, and they can interact with the AiInterface's internal variables. For example, it can change permission levels, do computations in the background and save them to the internal dictionary (AiInterface.vars), and interact with the graphics display. For some examples see AiInterface.
To create new graphics display items, use the existing templates. A graphics display item is a subclass of Tk.Frame with a show() method. You can define a graphics display item as a class with any graphics you wish, and then to display it call its show() method, which will put it on the graphics display. It needs to be saved as a variable of AiInterface in order to be available for usage and interaction.
To define permission levels for system commands, update the AiInterface.permissions variable. This variable maps system commands into required permission level. To define the permission given to a certain user, update USERNAME_TO_PERMISSION_LEVEL in constants.py. This dictionary maps usernames to their permission level. By default, users receive permission levels of 3, and system commands require no permission.
To connect remotely to a server, you should pass its public IP address as the host parameter. If you are connected via a public network or a router, your public IP is the address of that network/router, and you have to make sure that the server starts on a port which is routed to your machine upon incoming connections to your network/router.
If you want to let someone connect to your server from a remote machine without access to the rest of your code, they can run a local copy of server.clients.py as a main file. You just have to make sure you have the same system constants, as defined in the try-except block in the beginning of clients.py.