asthetics

Former-commit-id: 1b13823e4e31327dad280a82252be969f845efe8

core/router/router_wrapper.go

@@ -0,0 +1,52 @@
+package router
+
+import "net/http"
+
+// WrapperFunc is used as an expected input parameter signature
+// for the WrapRouter. It's a "low-level" signature which is compatible
+// with the net/http.
+// It's being used to run or no run the router based on a custom logic.
+type WrapperFunc func(w http.ResponseWriter, r *http.Request, router http.HandlerFunc)
+
+func makeWrapperFunc(original WrapperFunc, wrapperFunc WrapperFunc) WrapperFunc {
+	if wrapperFunc == nil {
+		return original
+	}
+
+	if original != nil {
+		// wrap into one function, from bottom to top, end to begin.
+		nextWrapper := wrapperFunc
+		prevWrapper := original
+		wrapperFunc = func(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
+			if next != nil {
+				nexthttpFunc := http.HandlerFunc(func(_w http.ResponseWriter, _r *http.Request) {
+					prevWrapper(_w, _r, next)
+				})
+				nextWrapper(w, r, nexthttpFunc)
+			}
+		}
+	}
+
+	return wrapperFunc
+}
+
+type wrapper struct {
+	router      http.HandlerFunc // http.HandlerFunc to catch the CURRENT state of its .ServeHTTP on case of future change.
+	wrapperFunc WrapperFunc
+}
+
+// newWrapper returns a new http.Handler wrapped by the 'wrapperFunc'
+// the "next" is the final "wrapped" input parameter.
+//
+// Application is responsible to make it to work on more than one wrappers
+// via composition or func clojure.
+func newWrapper(wrapperFunc WrapperFunc, wrapped http.HandlerFunc) http.Handler {
+	return &wrapper{
+		wrapperFunc: wrapperFunc,
+		router:      wrapped,
+	}
+}
+
+func (wr *wrapper) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	wr.wrapperFunc(w, r, wr.router)
+}