Make HTTP middleware easier to use

appengine/cmd/helloworld_mvm/frontend/main.go

Index: appengine/cmd/helloworld_mvm/frontend/main.go
diff --git a/appengine/cmd/helloworld_mvm/frontend/main.go b/appengine/cmd/helloworld_mvm/frontend/main.go
index 94255c731276bab14fbed5b375f7d888dfeb7f5a..a3a79cadc0973aa4a317adfe371b11ef57352951 100644
--- a/appengine/cmd/helloworld_mvm/frontend/main.go
+++ b/appengine/cmd/helloworld_mvm/frontend/main.go
@@ -3,29 +3,28 @@
 // that can be found in the LICENSE file.
 
 // Package main implements HTTP server that handles requests to default
 // module.
 package main
 
 import (
 	"net/http"
 	"strings"
 
-	"github.com/julienschmidt/httprouter"
 	"golang.org/x/net/context"
 	"google.golang.org/appengine"
 
 	"github.com/luci/gae/service/info"
 	"github.com/luci/luci-go/appengine/gaeauth/server"
 	"github.com/luci/luci-go/appengine/gaemiddleware"
 	"github.com/luci/luci-go/server/auth"
-	"github.com/luci/luci-go/server/middleware"
+	"github.com/luci/luci-go/server/router"
 	"github.com/luci/luci-go/server/templates"
 )
 
 // templateBundle is used to render HTML templates. It provides a base args
 // passed to all templates.
 var templateBundle = &templates.Bundle{
 	Loader:    templates.FileSystemLoader("templates"),
 	DebugMode: appengine.IsDevAppServer(),
 	DefaultArgs: func(c context.Context) (templates.Args, error) {
 		loginURL, err := auth.LoginURL(c, "/")
@@ -44,38 +43,41 @@ var templateBundle = &templates.Bundle{
 			"AppVersion":  strings.Split(info.Get(c).VersionID(), ".")[0],
 			"IsAnonymous": auth.CurrentIdentity(c) == "anonymous:anonymous",
 			"IsAdmin":     isAdmin,
 			"User":        auth.CurrentUser(c),
 			"LoginURL":    loginURL,
 			"LogoutURL":   logoutURL,
 		}, nil
 	},
 }
 
-// base is the root of the middleware chain.
-func base(h middleware.Handler) httprouter.Handle {
+// base returns the root middleware chain.
+func base() router.MiddlewareChain {
 	methods := auth.Authenticator{
 		&server.OAuth2Method{Scopes: []string{server.EmailScope}},
 		server.CookieAuth,
 		&server.InboundAppIDAuthMethod{},
 	}
-	h = auth.Use(h, methods)
-	h = templates.WithTemplates(h, templateBundle)
-	return gaemiddleware.BaseProd(h)
+	return append(
+		gaemiddleware.BaseProd(),
+		templates.WithTemplates(templateBundle),
+		auth.Use(methods),
+	)
 }
 
 //// Routes.
 
 func main() {
-	router := httprouter.New()
-	gaemiddleware.InstallHandlers(router, base)
-	router.GET("/", base(auth.Authenticate(indexPage)))
-	http.DefaultServeMux.Handle("/", router)
+	r := router.New()
+	basemw := base()
+	gaemiddleware.InstallHandlers(r, basemw)
+	r.GET("/", append(basemw, auth.Authenticate), indexPage)
+	http.DefaultServeMux.Handle("/", r)
 
 	appengine.Main()
 }
 
 //// Handlers.
 
-func indexPage(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) {
-	templates.MustRender(c, w, "pages/index.html", nil)
+func indexPage(c *router.Context) {
+	templates.MustRender(c.Context, c.Writer, "pages/index.html", nil)
 }