🐛 bug: fix proxy overwrote the wrong scheme (gofiber#2004)

* 🐛 bug: fix proxy overwrote the wrong scheme

* ✅ fix: fix io not exist in go1.14

Author: wangjq4214

middleware/proxy/proxy.go

@@ -123,11 +123,13 @@ func Do(c *fiber.Ctx, addr string) error {
 	res := c.Response()
 	originalURL := utils.CopyString(c.OriginalURL())
 	defer req.SetRequestURI(originalURL)
-	req.SetRequestURI(addr)
+
+	copiedURL := utils.CopyString(addr)
+	req.SetRequestURI(copiedURL)
 	// NOTE: if req.isTLS is true, SetRequestURI keeps the scheme as https.
 	// issue reference:
 	// https://github.com/gofiber/fiber/issues/1762
-	if scheme := getScheme(utils.UnsafeBytes(addr)); len(scheme) > 0 {
+	if scheme := getScheme(utils.UnsafeBytes(copiedURL)); len(scheme) > 0 {
 		req.URI().SetSchemeBytes(scheme)
 	}
 

middleware/proxy/proxy_test.go

@@ -4,6 +4,7 @@ import (
 	"crypto/tls"
 	"io/ioutil"
 	"net"
+	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
@@ -362,3 +363,30 @@ func Test_Proxy_Do_RestoreOriginalURL(t *testing.T) {
 	utils.AssertEqual(t, nil, err1)
 	utils.AssertEqual(t, nil, err2)
 }
+
+func Test_Proxy_Do_HTTP_Prefix_URL(t *testing.T) {
+	t.Parallel()
+
+	_, addr := createProxyTestServer(func(c *fiber.Ctx) error {
+		return c.SendString("hello world")
+	}, t)
+
+	app := fiber.New(fiber.Config{DisableStartupMessage: true})
+	app.Get("/*", func(c *fiber.Ctx) error {
+		path := c.OriginalURL()
+		url := strings.TrimPrefix(path, "/")
+
+		utils.AssertEqual(t, "http://"+addr, url)
+		if err := Do(c, url); err != nil {
+			return err
+		}
+		c.Response().Header.Del(fiber.HeaderServer)
+		return nil
+	})
+
+	resp, err := app.Test(httptest.NewRequest(http.MethodGet, "/http://"+addr, nil))
+	utils.AssertEqual(t, nil, err)
+	s, err := ioutil.ReadAll(resp.Body)
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, "hello world", string(s))
+}