refactor: websockets into 'connect' module, rename & adjust generally

internal/connect/listen.go

@@ -0,0 +1,70 @@
+package connect
+
+import (
+	"encoding/json"
+	"log/slog"
+
+	"github.com/gorilla/websocket"
+)
+
+// BaseMessage is the base message type for all messages sent by the websocket server.
+type BaseMessage struct {
+	Type    string `json:"type"`
+	Id      int64  `json:"id"`
+	Success bool   `json:"success"` // not present in all messages
+}
+
+type ChannelMessage struct {
+	Id      int64
+	Type    string
+	Success bool
+	Raw     []byte
+}
+
+// ListenWebsocket reads messages from the websocket connection and sends them to the channel.
+// It will close the channel if it encounters an error, or if the channel is full, and return.
+// It ignores errors in deserialization.
+func ListenWebsocket(conn *websocket.Conn, c chan ChannelMessage) {
+	for {
+		raw, err := ReadMessageRaw(conn)
+		if err != nil {
+			slog.Error("Error reading from websocket", "err", err)
+			close(c)
+			break
+		}
+
+		base := BaseMessage{
+			// default to true for messages that don't include "success" at all
+			Success: true,
+		}
+		err = json.Unmarshal(raw, &base)
+		if err != nil {
+			slog.Error("Error unmarshalling message", "err", err, "message", string(raw))
+			continue
+		}
+		if !base.Success {
+			slog.Warn("Received unsuccessful response", "response", string(raw))
+		}
+
+		// Create a channel message from the raw message
+		channelMessage := ChannelMessage{
+			Type:    base.Type,
+			Id:      base.Id,
+			Success: base.Success,
+			Raw:     raw,
+		}
+
+		// Use non-blocking send to avoid hanging on closed channel
+		select {
+		case c <- channelMessage:
+			// Message sent successfully
+		default:
+			// Channel is full or closed, break out of loop
+			slog.Warn("Websocket message channel is full or closed, stopping listener",
+				"channel_capacity", cap(c),
+				"channel_length", len(c))
+			close(c)
+			return
+		}
+	}
+}