Make HTTP middleware easier to use

server/auth/context.go

Index: server/auth/context.go
diff --git a/server/auth/context.go b/server/auth/context.go
index 035d59fb1472ae58d5c8b58da3e21409c92e40fe..5e84fd292944bc799f82d9fdcf13f7d830351f0e 100644
--- a/server/auth/context.go
+++ b/server/auth/context.go
@@ -8,14 +8,13 @@ import (
 	"fmt"
 	"net/http"
 
-	"github.com/julienschmidt/httprouter"
 	"golang.org/x/net/context"
 
 	"github.com/luci/luci-go/common/errors"
 	"github.com/luci/luci-go/common/logging"
 
 	"github.com/luci/luci-go/server/auth/identity"
-	"github.com/luci/luci-go/server/middleware"
+	"github.com/luci/luci-go/server/router"
 )
 
 type authenticatorKey int
@@ -37,9 +36,9 @@ func GetAuthenticator(c context.Context) Authenticator {
 }
 
 // Use is a middleware that simply puts given Authenticator into the context.
-func Use(h middleware.Handler, a Authenticator) middleware.Handler {
-	return func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-		h(SetAuthenticator(c, a), rw, r, p)
+func Use(a Authenticator) router.Handler {
+	return func(c *router.Context) {
+		c.Context = SetAuthenticator(c.Context, a)
 	}
 }
 
@@ -59,21 +58,24 @@ func LogoutURL(c context.Context, dest string) (string, error) {
 
 // Authenticate returns a wrapper around middleware.Handler that performs
 // authentication (using Authenticator in the context) and calls `h`.
-func Authenticate(h middleware.Handler) middleware.Handler {
-	return func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-		a := GetAuthenticator(c)
+func Authenticate() router.Handler {
+	return func(c *router.Context) {
+		a := GetAuthenticator(c.Context)
 		if a == nil {
-			replyError(c, rw, 500, "Authentication middleware is not configured")
+			replyError(c.Context, c.Writer, 500, "Authentication middleware is not configured")
+			c.Abort()
 			return
 		}
-		ctx, err := a.Authenticate(c, r)
+		ctx, err := a.Authenticate(c.Context, c.Request)
 		switch {
 		case errors.IsTransient(err):
-			replyError(c, rw, 500, fmt.Sprintf("Transient error during authentication - %s", err))
+			replyError(c.Context, c.Writer, 500, fmt.Sprintf("Transient error during authentication - %s", err))
+			c.Abort()
 		case err != nil:
-			replyError(c, rw, 401, fmt.Sprintf("Authentication error - %s", err))
+			replyError(c.Context, c.Writer, 401, fmt.Sprintf("Authentication error - %s", err))
+			c.Abort()
 		default:
-			h(ctx, rw, r, p)
+			c.Context = ctx
 		}
 	}
 }
@@ -81,44 +83,48 @@ func Authenticate(h middleware.Handler) middleware.Handler {
 // Autologin is a middleware that redirects the user to login page if the user
 // is not signed in yet or authentication methods do not recognize user
 // credentials. Uses Authenticator instance in the context.
-func Autologin(h middleware.Handler) middleware.Handler {
-	return func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-		a := GetAuthenticator(c)
+func Autologin() router.Handler {
+	return func(c *router.Context) {
+		a := GetAuthenticator(c.Context)
 		if a == nil {
-			replyError(c, rw, 500, "Authentication middleware is not configured")
+			replyError(c.Context, c.Writer, 500, "Authentication middleware is not configured")
+			c.Abort()
 			return
 		}
-		ctx, err := a.Authenticate(c, r)
+		ctx, err := a.Authenticate(c.Context, c.Request)
 
 		switch {
 		case errors.IsTransient(err):
-			replyError(c, rw, 500, fmt.Sprintf("Transient error during authentication - %s", err))
+			replyError(c.Context, c.Writer, 500, fmt.Sprintf("Transient error during authentication - %s", err))
+			c.Abort()
 
 		case err != nil:
-			replyError(c, rw, 401, fmt.Sprintf("Authentication error - %s", err))
+			replyError(c.Context, c.Writer, 401, fmt.Sprintf("Authentication error - %s", err))
+			c.Abort()
 
 		case CurrentIdentity(ctx).Kind() == identity.Anonymous:
-			dest := r.RequestURI
+			dest := c.Request.RequestURI
 			if dest == "" {
 				// Make r.URL relative.
-				destURL := *r.URL
+				destURL := *c.Request.URL
 				destURL.Host = ""
 				destURL.Scheme = ""
 				dest = destURL.String()
 			}
-			url, err := a.LoginURL(c, dest)
+			url, err := a.LoginURL(c.Context, dest)
 			if err != nil {
 				if errors.IsTransient(err) {
-					replyError(c, rw, 500, fmt.Sprintf("Transient error during authentication - %s", err))
+					replyError(c.Context, c.Writer, 500, fmt.Sprintf("Transient error during authentication - %s", err))
 				} else {
-					replyError(c, rw, 401, fmt.Sprintf("Authentication error - %s", err))
+					replyError(c.Context, c.Writer, 401, fmt.Sprintf("Authentication error - %s", err))
 				}
+				c.Abort()
 				return
 			}
-			http.Redirect(rw, r, url, 302)
+			http.Redirect(c.Writer, c.Request, url, 302)
 
 		default:
-			h(ctx, rw, r, p)
+			c.Context = ctx
 		}
 	}
 }