03-data-structures.md

Populate ChatRoom and ChatUser (5-10 minutes)

Goals

In this lesson, we'll setup the ChatRoom and ChatUser structs.

Let's review the design of the data structures and some of the requirements:

1. There is one ChatRoom in the app.
2. The ChatRoom must know about all of the active connections.
3. Each connection is tracked in a ChatUser object.
4. The ChatRoom must be able to receive messages from a single connection, and replay it back to the other connections. Otherwise, it will not be a very good chatroom!
5. When a new connection is established, the ChatRoom must be notified of these new connections.

Steps

1. Find the ChatRoom struct in chat.go.

type ChatRoom struct {
  // TODO: populate this   
}

1. 🌟 Add to the ChatRoom struct: * a private member users of type map[string]*ChatUser * a private member channel incoming of type chan string * a private member channel joins of type chan *ChatUser * a private member channel disconnects of type chan string
2. 🌟 Initialize all of these data structures in the NewChatRoom() constructor.

Stuck on any of the steps above? Ask your TA, or see the solution!

1. Find the ChatUser struct in chat.go.

type ChatUser struct {
  // TODO: populate this   
}

1. 🌟 Add to the ChatUser struct * a private member conn of type net.Conn * a private member disconnect of type bool * a private member username of type string * a private member channel outgoing of type chan string * a private member reader of type *bufio.Reader * a private member writer of type *bufio.Writer
2. 🌟 Initialize all of these data structures in the NewChatUser() constructor. * bufio.NewReader/bufio.NewWriter should accept the conn to create the reader and writer variables. * disconnect should be initially set to false

Stuck on any of the steps above? Ask your TA, or see the solution!

1. Don't worry too much about what all of these variables are for right now. As we fill out the rest of the code, you will gain a better understanding of what they will be used for, or you can ask your TA for more information.

You can also view the comments on the structs here.

1. Verify the code still runs when you type go run chat.go.

Next, proceed to Lesson 4 - where we actually read something from the user socket!