Issues with Viewport SetContent

[jamesthesken]

Hey Charm team, thank you for this library as it's been very inspiring and fun to work with!

I am working on an IRC client, and having some trouble updating the Viewport component:
https://github.com/jamesthesken/go-irc/tree/tui_v1

The Issue

In go-irc/tui/tui.go there is a function called StartTea(), which starts a goroutine that listens for incoming messages from an IRC server.

This function, Read() calls model.Update(RcvMessage{content: msgRcv}), where RcvMessage is defined as:

type RcvMessage struct {
	content string
}

After this message is received it is processed by a switch statement in Update():

case RcvMessage:
		// this does not work:
		m.messages = append(m.messages, m.senderStyle.Render("Server: ")+string(msg.content))
		m.viewport.SetContent(strings.Join(m.messages, "\n"))
		fmt.Print(msg.content) // but this does ??
		m.viewport.GotoBottom()

I can't seem to figure it out, but I can print the message contents to the screen, yet setting content in the Viewport does not work as expected. Even with a dummy string (I.e., m.viewport.SetContent("received")

Could there be a race condition between my message retrieval goroutine and updating the viewport?

Thank you in advance for any help and insight!

[muesli]

You shouldn't call model.Update directly: either send a message to the tea.Program or wrap the IRC handling in a tea.Command. Bubble Tea will then handle your messages, call Update and re-render the state of your program.

[jamesthesken]

You shouldn't call model.Update directly: either send a message to the tea.Program or wrap the IRC handling in a tea.Command. Bubble Tea will then handle your messages, call Update and re-render the state of your program.

Thank you so much! That is a great feature. I got it working by sending a message to the tea program:

func (m Model) Read(conn io.ReadWriter, p *tea.Program) {
	s := bufio.NewScanner(conn)
	for s.Scan() {
		line := s.Text()
		msgRcv := fmt.Sprintf(client.ParseMessage(line), "\n")
		p.Send(RcvMessage{content: msgRcv})
	}
	if s.Err() != nil {
		log.Fatalf("Error occured: %s", s.Err())
	}
}

[jamesthesken]

In case anyone comes back to this discussion, I think another useful example would be: https://github.com/charmbracelet/bubbletea/blob/master/examples/realtime/main.go

Rather than spinning up a goroutine to listen for incoming messages