Make HTTP middleware easier to use

appengine/cmd/milo/settings/settings.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 settings
 
 import (
         "encoding/base64"
         "encoding/json"
         "fmt"
         "net/http"
 
-        "github.com/julienschmidt/httprouter"
         "github.com/luci/gae/service/datastore"
         "github.com/luci/luci-go/appengine/cmd/milo/model"
         "github.com/luci/luci-go/appengine/cmd/milo/resp"
         "github.com/luci/luci-go/server/auth"
         "github.com/luci/luci-go/server/auth/identity"
         "github.com/luci/luci-go/server/auth/xsrf"
+        "github.com/luci/luci-go/server/router"
         "golang.org/x/net/context"
 )
 
 type updateReq struct {
         Theme string
 }
 
 // GetTheme returns the chosen theme based on the current user.
 func GetTheme(c context.Context, r *http.Request) Theme {
         cfg := getUserSettings(c)
@@ skipping 38 matching lines @@
         }
         err = json.Unmarshal([]byte(s), &config)
         if err != nil {
                 panic(err)
         }
         return &config
 }
 
 // ChangeSettings is invoked in a POST request to settings and changes either
 // the user settings in the datastore, or the cookies if user is anon.
-func ChangeSettings(c context.Context, h http.ResponseWriter, r *http.Request, p httprouter.Params) {
+func ChangeSettings(c *router.Context) {
         // First, check XSRF token.
-        err := xsrf.Check(c, r.FormValue("xsrf_token"))
+        err := xsrf.Check(c.Context, c.Request.FormValue("xsrf_token"))
         if err != nil {
-                h.WriteHeader(http.StatusUnauthorized)
-                h.Write([]byte("Failed XSRF check."))
+                c.Writer.WriteHeader(http.StatusUnauthorized)
+                c.Writer.Write([]byte("Failed XSRF check."))
                 return
         }
 
         u := &updateReq{
-                Theme: r.FormValue("theme"),
+                Theme: c.Request.FormValue("theme"),
         }
         validateUpdate(u)
-        s := getUserSettings(c)
+        s := getUserSettings(c.Context)
         if s == nil {
                 // User doesn't exist, just respond with a cookie.
-                s = getCookieSettings(c, r)
+                s = getCookieSettings(c.Context, c.Request)
                 s.Theme = u.Theme
-                setCookieSettings(h, s)
+                setCookieSettings(c.Writer, s)
         } else {
-                changeUserSettings(c, u)
+                changeUserSettings(c.Context, u)
         }
 
         // Redirect to the GET endpoint.
-        http.Redirect(h, r, r.URL.String(), http.StatusSeeOther)
+        http.Redirect(c.Writer, c.Request, c.Request.URL.String(), http.StatusSeeOther)
 }
 
 // setCookieSettings sets the cfg object as a base64 json serialized string.
 func setCookieSettings(h http.ResponseWriter, cfg *model.UserConfig) {
         s, err := json.Marshal(cfg)
         if err != nil {
                 panic(err)
         }
         bs := base64.StdEncoding.EncodeToString(s)
         cookie := http.Cookie{
@@ skipping 28 matching lines @@
 
         result := &resp.Settings{}
         result.ActionURL = r.URL.String()
         result.Theme = &resp.Choices{
                 Choices:  GetAllThemes(),
                 Selected: userSettings.Theme,
         }
 
         return result, nil
 }