chat

Chatty

COMP 429 Programming Assignment 1
A Chat Application for Remote Message Exchange
by Sabra Bilodeau

Getting Started with Chatty

Building the Program

1. Download Go, if you don't already have it installed on your local machine.
2. Download the source code via one of these two methods
   a. Clone the repository by running git clone https://github.com/Cryliss/comp-429.git in the terminal
   b. Download the source code directly from GitHub, and place it in your Go source code directory - e.g. /Users/sabra/go/src
3. From terminal, navigate to the chat application directory. e.g. cd ~/go/src/chat
4. Run make build to build the applications binary file

make build builds the program with the --race flag in order to help catch any data races that may occur within our application due to the goroutines. (ideally none will, but just in case .. )
An example (that has since been corrected!) is below:

==================
WARNING: DATA RACE
Write at 0x00c0001247e0 by goroutine 7:
  runtime.mapassign_fast32()
      /usr/local/go/src/runtime/map_fast32.go:92 +0x0
  chat/server.(*Server).Run()
      /Users/sabra/go/src/chat/server/core.go:101 +0x3be

Previous read at 0x00c0001247e0 by main goroutine:
  runtime.mapiternext()
      /usr/local/go/src/runtime/map.go:851 +0x0
  chat/server.(*Server).List()
      /Users/sabra/go/src/chat/server/core.go:211 +0x167
  chat/app.(*Application).ParseInput()
      /Users/sabra/go/src/chat/app/core.go:140 +0x484
  main.main()
      /Users/sabra/go/src/chat/bin/chat/main.go:65 +0x42a

Goroutine 7 (running) created at:
  main.main()
      /Users/sabra/go/src/chat/bin/chat/main.go:46 +0x353
==================

Running the Program

Starting the program can be done by entering one of two commands into terminal:

1. ./chat -port <port no>
2. make run will automatically run on port 8888

Application Starting Output

CHATTY: A Chat Application for Remote Message Exchange
------------------------------------------------------
Available commands:
    1. help
    2. myip
    3. myport
    4. connect <destination> <port no>
    5. list
    6. terminate <connection id>
    7. send <connection id> <message>
    8. exit

You may either type the command name, i.e. 'connect <destination> <port no>', or the command number, i.e. '4 <destination> <port no>'
Type 'help' for an explanation of each command, or type 'help <command>' to get the explanation for a specific command

Please enter a command:

Programming Assignment Details

Environment Requirements

(1) Use TCP Sockets in your peer connection implementation
(2) Use the select() API or multi-threads for handling multiple socket connections
(3) Integrate both client-side and server-side code into one program and run on each peer

Functional Requirements

• help: Display information about the available user interface options or command manual.
• myip: Display the IP address of this process.
• myport: Display the port on which this process is listening for incoming connections.
• connect {destination} {port no}:
  • This command establishes a new TCP connection to the specified {destination} at the specified {port no}. The {destination} is the IP address of the computer.
  • Any attempt to connect to an invalid IP should be rejected and suitable error message should be displayed.
  • Success or failure in connections between two peers should be indicated by both the peers using suitable messages.
  • Self-connections and duplicate connections should be flagged with suitable error messages.
• list:
  • Display a numbered list of all the connections this process is part of.
  • This numbered list will include connections initiated by this process and connections initiated by other processes.
  • The output should display the IP address and the listening port of all the peers the process is connected to.
• terminate {connection id}:
  • This command will terminate the connection listed under the specified number when 'list' is used to display all connections.
  • An error message is displayed if a valid connection does not exist.
  • If a remote machine terminates one of your connections, you should also display a message.
• send {connection id} {message}:
  • This will send the message to the host on the connection that is designated by the {connection id} when command “list” is used.
  • The message to be sent can be up-to 100 characters long, including blank spaces.
  • On successfully executing the command, the sender should display “Message sent to {connection id}” on the screen.
  • On receiving any message from the peer, the receiver should display the received message along with the sender information.
• exit:
  • Close all connections and terminate this process.
  • The other peers should also update their connection list by removing the peer that exits.