Make HTTP middleware easier to use

appengine/cmd/cron/ui/invocation.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 ui
 
 import (
         "fmt"
         "net/http"
         "strconv"
 
-        "github.com/julienschmidt/httprouter"
-        "golang.org/x/net/context"
-
         "github.com/luci/luci-go/common/clock"
         "github.com/luci/luci-go/server/auth"
+        "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/templates"
 )
 
-func invocationPage(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) {
-        projectID := p.ByName("ProjectID")
-        jobID := p.ByName("JobID")
-        invID, err := strconv.ParseInt(p.ByName("InvID"), 10, 64)
+func invocationPage(c *router.Context) {
+        projectID := c.Params.ByName("ProjectID")
+        jobID := c.Params.ByName("JobID")
+        invID, err := strconv.ParseInt(c.Params.ByName("InvID"), 10, 64)
         if err != nil {
-                http.Error(w, "No such invocation", http.StatusNotFound)
+                http.Error(c.Writer, "No such invocation", http.StatusNotFound)
                 return
         }
 
-        inv, err := config(c).Engine.GetInvocation(c, projectID+"/"+jobID, invID)
+        inv, err := config(c.Context).Engine.GetInvocation(c.Context, projectID+"/"+jobID, invID)
         if err != nil {
                 panic(err)
         }
         if inv == nil {
-                http.Error(w, "No such invocation", http.StatusNotFound)
+                http.Error(c.Writer, "No such invocation", http.StatusNotFound)
                 return
         }
 
-        now := clock.Now(c).UTC()
-        templates.MustRender(c, w, "pages/invocation.html", map[string]interface{}{
+        now := clock.Now(c.Context).UTC()
+        templates.MustRender(c.Context, c.Writer, "pages/invocation.html", map[string]interface{}{
                 "ProjectID": projectID,
                 "JobID":     jobID,
                 "Inv":       makeInvocation(projectID, jobID, inv, now),
         })
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Actions.
 
-func abortInvocationAction(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) {
-        handleInvAction(c, w, r, p, func(jobID string, invID int64) error {
-                who := auth.CurrentIdentity(c)
-                return config(c).Engine.AbortInvocation(c, jobID, invID, who)
+func abortInvocationAction(c *router.Context) {
+        handleInvAction(c, func(jobID string, invID int64) error {
+                who := auth.CurrentIdentity(c.Context)
+                return config(c.Context).Engine.AbortInvocation(c.Context, jobID, invID, who)
         })
 }
 
-func handleInvAction(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params, cb func(string, int64) error) {
-        projectID := p.ByName("ProjectID")
-        jobID := p.ByName("JobID")
-        invID := p.ByName("InvID")
-        if !isJobOwner(c, projectID, jobID) {
-                http.Error(w, "Forbidden", 403)
+func handleInvAction(c *router.Context, cb func(string, int64) error) {
+        projectID := c.Params.ByName("ProjectID")
+        jobID := c.Params.ByName("JobID")
+        invID := c.Params.ByName("InvID")
+        if !isJobOwner(c.Context, projectID, jobID) {
+                http.Error(c.Writer, "Forbidden", 403)
                 return
         }
         invIDAsInt, err := strconv.ParseInt(invID, 10, 64)
         if err != nil {
-                http.Error(w, "Bad invocation ID", 400)
+                http.Error(c.Writer, "Bad invocation ID", 400)
                 return
         }
         if err := cb(projectID+"/"+jobID, invIDAsInt); err != nil {
                 panic(err)
         }
-        http.Redirect(w, r, fmt.Sprintf("/jobs/%s/%s/%s", projectID, jobID, invID), http.StatusFound)
+        http.Redirect(c.Writer, c.Request, fmt.Sprintf("/jobs/%s/%s/%s", projectID, jobID, invID), http.StatusFound)
 }