Make HTTP middleware easier to use

appengine/gaeauth/server/internal/authdb/handlers.go

Index: appengine/gaeauth/server/internal/authdb/handlers.go
diff --git a/appengine/gaeauth/server/internal/authdb/handlers.go b/appengine/gaeauth/server/internal/authdb/handlers.go
index 574604ea2d969bfc12e2a438031b6a06e4b70642..db604f13925f5c5f59506421aaf2eb53d01674f6 100644
--- a/appengine/gaeauth/server/internal/authdb/handlers.go
+++ b/appengine/gaeauth/server/internal/authdb/handlers.go
@@ -10,7 +10,6 @@ import (
 	"net/http"
 	"net/url"
 
-	"github.com/julienschmidt/httprouter"
 	"golang.org/x/net/context"
 	"google.golang.org/appengine"
 
@@ -20,7 +19,7 @@ import (
 	"github.com/luci/luci-go/common/errors"
 	"github.com/luci/luci-go/common/logging"
 	"github.com/luci/luci-go/server/auth/service"
-	"github.com/luci/luci-go/server/middleware"
+	"github.com/luci/luci-go/server/router"
 )
 
 const (
@@ -29,11 +28,11 @@ const (
 )
 
 // InstallHandlers installs PubSub related HTTP handlers.
-func InstallHandlers(r *httprouter.Router, base middleware.Base) {
+func InstallHandlers(r *router.Router, handlers []router.Handler) {
 	if appengine.IsDevAppServer() {
-		r.GET(pubSubPullURLPath, base(pubSubPull))
+		r.GET(pubSubPullURLPath, append(handlers, pubSubPull)...)
 	}
-	r.POST(pubSubPushURLPath, base(pubSubPush))
+	r.POST(pubSubPushURLPath, append(handlers, pubSubPush)...)
 }
 
 // authenticatePubSub injects into a context a transport that authenticates
@@ -82,12 +81,13 @@ func subscriptionName(c context.Context, authServiceURL string) string {
 //
 // Used only on dev server for manual testing. Prod services use push-based
 // delivery.
-func pubSubPull(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
+func pubSubPull(ctx *router.Context) {
 	if !appengine.IsDevAppServer() {
-		replyError(c, rw, errors.New("not a dev server"))
+		replyError(ctx.Context, ctx.Writer, errors.New("not a dev server"))
+		ctx.Abort()
 		return
 	}
-	processPubSubRequest(c, rw, r, func(c context.Context, srv authService, serviceURL string) (*service.Notification, error) {
+	processPubSubRequest(ctx, func(c context.Context, srv authService, serviceURL string) (*service.Notification, error) {
 		return srv.PullPubSub(c, subscriptionName(c, serviceURL))
 	})
 }
@@ -96,9 +96,9 @@ func pubSubPull(c context.Context, rw http.ResponseWriter, r *http.Request, p ht
 //
 // It uses the signature inside PubSub message body for authentication. Skips
 // messages not signed by currently configured auth service.
-func pubSubPush(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-	processPubSubRequest(c, rw, r, func(c context.Context, srv authService, serviceURL string) (*service.Notification, error) {
-		body, err := ioutil.ReadAll(r.Body)
+func pubSubPush(ctx *router.Context) {
+	processPubSubRequest(ctx, func(c context.Context, srv authService, serviceURL string) (*service.Notification, error) {
+		body, err := ioutil.ReadAll(ctx.Request.Body)
 		if err != nil {
 			return nil, err
 		}
@@ -113,30 +113,32 @@ type notifcationGetter func(context.Context, authService, string) (*service.Noti
 // It implements most logic of notification handling. Calls supplied callback
 // to actually get service.Notification, since this part is different from Pull
 // and Push subscriptions.
-func processPubSubRequest(c context.Context, rw http.ResponseWriter, r *http.Request, callback notifcationGetter) {
-	c = defaultNS(c)
-	c = authenticatePubSub(c)
-	info, err := GetLatestSnapshotInfo(c)
+func processPubSubRequest(c *router.Context, callback notifcationGetter) {
+	c.Context = defaultNS(c.Context)
+	c.Context = authenticatePubSub(c.Context)
+	info, err := GetLatestSnapshotInfo(c.Context)
 	if err != nil {
-		replyError(c, rw, err)
+		replyError(c.Context, c.Writer, err)
+		c.Abort()
 		return
 	}
 	if info == nil {
 		// Return HTTP 200 to avoid a redelivery.
-		replyOK(c, rw, "Auth Service URL is not configured, skipping the message")
+		replyOK(c.Context, c.Writer, "Auth Service URL is not configured, skipping the message")
 		return
 	}
-	srv := getAuthService(c, info.AuthServiceURL)
+	srv := getAuthService(c.Context, info.AuthServiceURL)
 
-	notify, err := callback(c, srv, info.AuthServiceURL)
+	notify, err := callback(c.Context, srv, info.AuthServiceURL)
 	if err != nil {
-		replyError(c, rw, err)
+		replyError(c.Context, c.Writer, err)
+		c.Abort()
 		return
 	}
 
 	// notify may be nil if PubSub messages didn't pass authentication.
 	if notify == nil {
-		replyOK(c, rw, "No new valid AuthDB change notifications")
+		replyOK(c.Context, c.Writer, "No new valid AuthDB change notifications")
 		return
 	}
 
@@ -144,19 +146,21 @@ func processPubSubRequest(c context.Context, rw http.ResponseWriter, r *http.Req
 	latest := info
 	if notify.Revision > info.Rev {
 		var err error
-		if latest, err = syncAuthDB(c); err != nil {
-			replyError(c, rw, err)
+		if latest, err = syncAuthDB(c.Context); err != nil {
+			replyError(c.Context, c.Writer, err)
+			c.Abort()
 			return
 		}
 	}
 
-	if err := notify.Acknowledge(c); err != nil {
-		replyError(c, rw, err)
+	if err := notify.Acknowledge(c.Context); err != nil {
+		replyError(c.Context, c.Writer, err)
+		c.Abort()
 		return
 	}
 
 	replyOK(
-		c, rw, "Processed PubSub notification for rev %d: %d -> %d",
+		c.Context, c.Writer, "Processed PubSub notification for rev %d: %d -> %d",
 		notify.Revision, info.Rev, latest.Rev)
 }