initial implementation

pkg/router/chain.go

@@ -0,0 +1,19 @@
+package router
+
+import (
+	"net/http"
+
+	"git.juancwu.dev/juancwu/lightmux/pkg/middleware"
+)
+
+// chain wraps h with groupMws followed by routeMws so that groupMws[0] is the
+// outermost layer (runs first on request, last on response).
+func chain(h http.Handler, groupMws, routeMws []middleware.Middleware) http.Handler {
+	all := make([]middleware.Middleware, 0, len(groupMws)+len(routeMws))
+	all = append(all, groupMws...)
+	all = append(all, routeMws...)
+	for i := len(all) - 1; i >= 0; i-- {
+		h = all[i](h)
+	}
+	return h
+}