refactor: rename internal/session package to internal/ctx

internal/bch/broadcast.go

@@ -0,0 +1,18 @@
+//go:build js && wasm
+
+package channel
+
+import (
+	"syscall/js"
+
+	"github.com/labstack/echo/v4"
+)
+
+type BroadcastContext struct {
+	echo.Context
+	Channel js.Value
+}
+
+func (c *BroadcastContext) BroadcastMessage(message string) {
+	c.Channel.Call("postMessage", message)
+}

internal/bch/middleware.go

@@ -0,0 +1,35 @@
+//go:build js && wasm
+
+package channel
+
+import (
+	"syscall/js"
+
+	"github.com/labstack/echo/v4"
+)
+
+type JSHandler func(this js.Value, args []js.Value) interface{}
+
+func UseBroadcastChannel(channelName string, handler JSHandler) echo.MiddlewareFunc {
+	var channel js.Value
+
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			if channel.IsUndefined() {
+				channel = js.Global().Get("BroadcastChannel").New(channelName)
+				channel.Call("addEventListener", "message", handler)
+			}
+
+			cc := &BroadcastContext{
+				Context: c,
+				Channel: channel,
+			}
+			return next(cc)
+		}
+	}
+}
+
+func PostBroadcastMessage(c echo.Context, message string) {
+	cc := c.(*BroadcastContext)
+	cc.BroadcastMessage(message)
+}