Make HTTP middleware easier to use

server/auth/db.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 auth
 
 import (
         "errors"
         "fmt"
         "net"
-        "net/http"
         "strings"
         "time"
 
-        "github.com/julienschmidt/httprouter"
         "golang.org/x/net/context"
 
         "github.com/luci/luci-go/common/clock"
         "github.com/luci/luci-go/common/lazyslot"
         "github.com/luci/luci-go/common/logging"
         "github.com/luci/luci-go/common/mathrand"
 
         "github.com/luci/luci-go/server/auth/identity"
         "github.com/luci/luci-go/server/auth/service/protocol"
-        "github.com/luci/luci-go/server/middleware"
+        "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/secrets"
 )
 
 // ErrNoDB is returned by default DB returned from GetDB if no DBFactory is
 // installed in the context.
 var ErrNoDB = errors.New("auth: using default auth.DB, install a properly mocked one instead")
 
 // DB is interface to access a database of authorization related information.
 //
 // It is static read only object that represent snapshot of auth data at some
@@ skipping 43 matching lines @@
 
 // dbKey is used for context.Context key of DBFactory.
 type dbKey int
 
 // UseDB sets a factory that creates DB instances.
 func UseDB(c context.Context, f DBFactory) context.Context {
         return context.WithValue(c, dbKey(0), f)
 }
 
 // WithDB is middleware that sets given DBFactory in the context before calling
-// a handler.
-func WithDB(h middleware.Handler, f DBFactory) middleware.Handler {
-        return func(c context.Context, rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-                h(UseDB(c, f), rw, r, p)
+// the next handler.
+func WithDB(f DBFactory) router.Middleware {
+        return func(c *router.Context, next router.Handler) {
+                c.Context = UseDB(c.Context, f)
+                next(c)
         }
 }
 
 // GetDB returns most recent snapshot of authorization database using factory
 // installed in the context via `UseDB`.
 //
 // If no factory is installed, returns DB that forbids everything and logs
 // errors. It is often good enough for unit tests that do not care about
 // authorization, and still not horribly bad if accidentally used in production.
 //
@@ skipping 346 matching lines @@
 // IP whitelist is a set of IP subnets. Unknown IP whitelists are considered
 // empty. May return errors if underlying datastore has issues.
 func (db *SnapshotDB) IsInWhitelist(c context.Context, ip net.IP, whitelist string) (bool, error) {
         for _, ipnet := range db.whitelists[whitelist] {
                 if ipnet.Contains(ip) {
                         return true, nil
                 }
         }
         return false, nil
 }