Make HTTP middleware easier to use

appengine/cmd/dm/distributor/pubsub.go

 // Copyright 2016 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 distributor
 
 import (
         "encoding/json"
         "fmt"
         "net/http"
         "strconv"
         "time"
 
-        "github.com/julienschmidt/httprouter"
         "github.com/luci/luci-go/appengine/tumble"
         "github.com/luci/luci-go/common/api/dm/service/v1"
         "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/tokens"
         "golang.org/x/net/context"
 )
 
 const notifyTopicSuffix = "dm-distributor-notify"
 
-// PubsubReciever is the HTTP handler that processes incoming pubsub events
+// PubsubReceiver is the HTTP handler that processes incoming pubsub events
 // delivered to topics prepared with TaskDescription.PrepareTopic, and routes
 // them to the appropriate distributor implementation's HandleNotification
 // method.
 //
 // It requires that a Registry be installed in c via WithRegistry.
-func PubsubReciever(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
+func PubsubReceiver(ctx *router.Context) {
+        c, rw, r := ctx.Context, ctx.Writer, ctx.Request
         defer r.Body.Close()
 
         type PubsubMessage struct {
                 Attributes map[string]string `json:"attributes"`
                 Data       []byte            `json:"data"`
                 MessageID  string            `json:"message_id"`
         }
         type PubsubPushMessage struct {
                 Message      PubsubMessage `json:"message"`
                 Subscription string        `json:"subscription"`
@@ skipping 71 matching lines @@
         }
         eid = dm.NewExecutionID(quest, uint32(attemptNum), uint32(executionNum))
 
         cfgName, ok := items["cfgName"]
         if !ok {
                 err = fmt.Errorf("missing config name")
         }
 
         return
 }