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refactor(net): reuse a single buffered reader; manage broadcast loop lifecycle

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Client:
- Keep a persistent bufio.Reader on the connection (model.reader)
- On connect, initialize reader and drain initial greetings with deadlines
- Pass reader into fetchMenuCmd, submitOrderCmd, and listenForBroadcastsCmd
- Avoid starting duplicate broadcast listeners with broadcastListening flag
- Start broadcast listener after menu is loaded and form is initialized
- Update commands to read via shared reader instead of creating new ones
- Remove greeting drain from connectCmd (now handled on connectedMsg)
- Minor: small flow tweaks for opening form and handling reconnection

Benefits:
- Prevents interleaved reads from multiple readers on the same net.Conn
- Reduces race conditions and broken protocol reads
- Ensures a single, continuous read loop for broadcasts and responses
This commit is contained in:
Syahdan 2025-10-15 22:43:35 +07:00
parent 616017267e
commit aee33003bf
1 changed files with 36 additions and 30 deletions
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66
main.go
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@ -70,6 +70,9 @@ type model struct {
width int
height int
reader *bufio.Reader
broadcastListening bool
}
// initialModel creates a base model.
@ -123,7 +126,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
m.err = nil
m.loading = true
m.status = "Submitting order..."
return m, submitOrderCmd(m.conn, *ord)
return m, submitOrderCmd(m.conn, *ord, m.reader)
}
m.status = "Order canceled."
return m, cmd
@ -141,8 +144,18 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
switch msg := msg.(type) {
case connectedMsg:
m.conn = msg.conn
m.reader = bufio.NewReader(m.conn)
m.status = fmt.Sprintf("Connected to %s", m.host)
return m, listenForBroadcastsCmd(m.conn)
_ = m.conn.SetReadDeadline(time.Now().Add(500 * time.Millisecond))
for i := 0; i < 2; i++ {
if _, err := m.reader.ReadString('\n'); err != nil {
break
}
}
_ = m.conn.SetReadDeadline(time.Time{})
return m, nil
case menuLoadedMsg:
m.loading = false
@ -154,9 +167,17 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
m.err = nil
m.menu = msg.items
m.status = "Menu loaded."
// Open the form now that we have a menu.
var cmds []tea.Cmd
m.form = m.buildForm()
return m, m.form.Init()
cmds = append(cmds, m.form.Init())
if !m.broadcastListening {
m.broadcastListening = true
cmds = append(cmds, listenForBroadcastsCmd(m.conn, m.reader))
}
return m, tea.Batch(cmds...)
case orderSubmittedMsg:
m.loading = false
@ -181,7 +202,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
m.broadcasts = m.broadcasts[1:]
}
}
return m, listenForBroadcastsCmd(m.conn)
return m, listenForBroadcastsCmd(m.conn, m.reader)
case statusMsg:
m.status = string(msg)
@ -203,7 +224,6 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
m.status = "Reconnecting..."
return m, connectCmd(m.host)
case "n":
// Start a new order
if m.loading || m.form != nil {
return m, nil
}
@ -218,7 +238,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
}
m.loading = true
m.status = "Loading menu..."
return m, fetchMenuCmd(m.conn)
return m, fetchMenuCmd(m.conn, m.reader)
}
case tea.WindowSizeMsg:
@ -447,15 +467,6 @@ func connectCmd(addr string) tea.Cmd {
if err != nil {
return statusMsg(fmt.Sprintf("Connect failed: %v", err))
}
// Try to read up to two greeting lines with short deadline (optional).
_ = conn.SetReadDeadline(time.Now().Add(500 * time.Millisecond))
br := bufio.NewReader(conn)
for i := 0; i < 2; i++ {
if _, err := br.ReadString('\n'); err != nil {
break
}
}
_ = conn.SetReadDeadline(time.Time{})
return connectedMsg{conn: conn}
}
@ -465,27 +476,24 @@ func connectCmd(addr string) tea.Cmd {
// Protocol (proposed):
// - client: "MENU\n"
// - server: single line JSON array: [{"id":"x","name":"..."}]\n
func fetchMenuCmd(conn net.Conn) tea.Cmd {
func fetchMenuCmd(conn net.Conn, reader *bufio.Reader) tea.Cmd {
return func() tea.Msg {
if conn == nil {
return menuLoadedMsg{err: errors.New("not connected")}
}
// Send request
if _, err := fmt.Fprintln(conn, "MENU"); err != nil {
return menuLoadedMsg{err: fmt.Errorf("send MENU: %w", err)}
}
// Read single JSON line
_ = conn.SetReadDeadline(time.Now().Add(3 * time.Second))
defer func() { _ = conn.SetReadDeadline(time.Time{}) }()
r := bufio.NewReader(conn)
line, err := r.ReadString('\n')
line, err := reader.ReadString('\n')
if err != nil {
return menuLoadedMsg{err: fmt.Errorf("read MENU: %w", err)}
}
line = strings.TrimRight(line, "\r\n")
// If the server sent an error-ish line, surface it.
if strings.HasPrefix(line, "[error]") {
return menuLoadedMsg{err: fmt.Errorf("server: %s", line)}
}
@ -502,7 +510,7 @@ func fetchMenuCmd(conn net.Conn) tea.Cmd {
// Protocol (proposed):
// - client: "ORDER <json>\n"
// - server: a single line acknowledgement (freeform), e.g. "OK\n"
func submitOrderCmd(conn net.Conn, ord order) tea.Cmd {
func submitOrderCmd(conn net.Conn, ord order, reader *bufio.Reader) tea.Cmd {
return func() tea.Msg {
if conn == nil {
return orderSubmittedMsg{err: errors.New("not connected")}
@ -516,11 +524,10 @@ func submitOrderCmd(conn net.Conn, ord order) tea.Cmd {
return orderSubmittedMsg{err: fmt.Errorf("send ORDER: %w", err)}
}
// Read single-line ack
_ = conn.SetReadDeadline(time.Now().Add(3 * time.Second))
defer func() { _ = conn.SetReadDeadline(time.Time{}) }()
r := bufio.NewReader(conn)
line, err := r.ReadString('\n')
line, err := reader.ReadString('\n')
if err != nil {
return orderSubmittedMsg{err: fmt.Errorf("read ORDER ack: %w", err)}
}
@ -537,13 +544,12 @@ func submitOrderCmd(conn net.Conn, ord order) tea.Cmd {
}
}
func listenForBroadcastsCmd(conn net.Conn) tea.Cmd {
func listenForBroadcastsCmd(conn net.Conn, reader *bufio.Reader) tea.Cmd {
return func() tea.Msg {
if conn == nil {
if conn == nil || reader == nil {
return nil
}
r := bufio.NewReader(conn)
line, err := r.ReadString('\n')
line, err := reader.ReadString('\n')
if err != nil {
return statusMsg(fmt.Sprintf("Connection closed: %v", err))
}