Refactor packages to have more idiomatic code base

http/middleware/middleware.go

@@ -0,0 +1,36 @@
+// Copyright 2017 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package middleware
+
+import (
+	"net/http"
+)
+
+// Middleware represents a HTTP middleware.
+type Middleware func(http.Handler) http.Handler
+
+// Chain handles a list of middlewares.
+type Chain struct {
+	middlewares []Middleware
+}
+
+// Wrap adds a HTTP handler into the chain.
+func (m *Chain) Wrap(h http.Handler) http.Handler {
+	for i := range m.middlewares {
+		h = m.middlewares[len(m.middlewares)-1-i](h)
+	}
+
+	return h
+}
+
+// WrapFunc adds a HTTP handler function into the chain.
+func (m *Chain) WrapFunc(fn http.HandlerFunc) http.Handler {
+	return m.Wrap(fn)
+}
+
+// NewChain returns a new Chain.
+func NewChain(middlewares ...Middleware) *Chain {
+	return &Chain{append(([]Middleware)(nil), middlewares...)}
+}