🧑‍💻 Created middleware package

internal/middleware/middleware.go

@@ -0,0 +1,44 @@
+package middleware
+
+import "net/http"
+
+type (
+	// Interceptor intercepts an HTTP handler invocation, it is passed both
+	// response writer and request which after interception can be passed
+	// onto the handler function.
+	Interceptor func(w http.ResponseWriter, r *http.Request, next http.HandlerFunc)
+
+	// HandlerFunc builds on top of http.HandlerFunc, and exposes API to
+	// intercept with Interceptor. This allows building complex long chains
+	// without complicated struct manipulation.
+	HandlerFunc http.HandlerFunc
+
+	// Chain is a collection of interceptors that will be invoked in there
+	// index order.
+	Chain []Interceptor
+
+	// Skipper is a requests checker for middleware configurations. true
+	// return force middleware to skip any actions with current request.
+	Skipper func(r *http.Request) bool
+)
+
+var DefaultSkipper Skipper = func(_ *http.Request) bool { return false }
+
+// Intercept returns back a continuation that will call install middleware to
+// intercept the continuation call.
+func (hf HandlerFunc) Intercept(i Interceptor) HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		i(w, r, http.HandlerFunc(hf))
+	}
+}
+
+// Handler allows hooking multiple middleware in single call.
+func (c Chain) Handler(hf http.HandlerFunc) http.Handler {
+	current := HandlerFunc(hf)
+
+	for i := len(c) - 1; i >= 0; i-- {
+		current = current.Intercept(c[i])
+	}
+
+	return http.HandlerFunc(current)
+}