Make HTTP middleware easier to use

appengine/cmd/helloworld_mvm/frontend/main.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // 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, "/")
@@ skipping 12 matching lines @@
                         "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)
 }