From 5eabae8e40c352579096b5677a5c175c3772a163 Mon Sep 17 00:00:00 2001
From: Anton Zadvorny <thcheetah@gmail.com>
Date: Mon, 25 Dec 2023 04:06:39 +0300
Subject: [PATCH] Add Wrap function to apply a list of middlewares on a handler

---
 middleware.go      | 19 +++++++++++++++++++
 middleware_test.go | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 middleware.go
 create mode 100644 middleware_test.go

diff --git a/middleware.go b/middleware.go
new file mode 100644
index 0000000..3aaae11
--- /dev/null
+++ b/middleware.go
@@ -0,0 +1,19 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+// Wrap converts a list of middlewares to nested calls in reverse order
+func Wrap(handler http.Handler, mws ...func(http.Handler) http.Handler) http.Handler {
+	if len(mws) == 0 {
+		return handler
+	}
+
+	res := handler
+	for i := len(mws) - 1; i >= 0; i-- {
+		res = mws[i](res)
+	}
+
+	return res
+}
diff --git a/middleware_test.go b/middleware_test.go
new file mode 100644
index 0000000..7d9e8db
--- /dev/null
+++ b/middleware_test.go
@@ -0,0 +1,36 @@
+package middleware
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestWrap(t *testing.T) {
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/something/1/2", r.URL.Path)
+	})
+
+	mw1 := func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			r.URL.Path += "/1"
+			h.ServeHTTP(w, r)
+		})
+	}
+	mw2 := func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			r.URL.Path += "/2"
+			h.ServeHTTP(w, r)
+		})
+	}
+
+	server := httptest.NewServer(Wrap(handler, mw1, mw2))
+	defer server.Close()
+
+	res, err := http.Get(server.URL + "/something")
+	require.NoError(t, err)
+	assert.Equal(t, 200, res.StatusCode)
+}