1// Copyright 2012 Google Inc. All rights reserved. 2// Use of this source code is governed by the Apache 2.0 3// license that can be found in the LICENSE file. 4 5package appengine 6 7import ( 8 "fmt" 9 "regexp" 10 11 "appengine_internal" 12 basepb "appengine_internal/base" 13 "appengine_internal/github.com/golang/protobuf/proto" 14) 15 16// Namespace returns a replacement context that operates within the given namespace. 17func Namespace(c Context, namespace string) (Context, error) { 18 if !validNamespace.MatchString(namespace) { 19 return nil, fmt.Errorf("appengine: namespace %q does not match /%s/", namespace, validNamespace) 20 } 21 return &namespacedContext{ 22 Context: c, 23 namespace: namespace, 24 }, nil 25} 26 27// validNamespace matches valid namespace names. 28var validNamespace = regexp.MustCompile(`^[0-9A-Za-z._-]{0,100}$`) 29 30// namespacedContext wraps a Context to support namespaces. 31type namespacedContext struct { 32 Context 33 namespace string 34} 35 36func (n *namespacedContext) Call(service, method string, in, out appengine_internal.ProtoMessage, opts *appengine_internal.CallOptions) error { 37 // Apply any namespace mods. 38 if mod, ok := appengine_internal.NamespaceMods[service]; ok { 39 mod(in, n.namespace) 40 } 41 if service == "__go__" && method == "GetNamespace" { 42 out.(*basepb.StringProto).Value = proto.String(n.namespace) 43 return nil 44 } 45 46 return n.Context.Call(service, method, in, out, opts) 47} 48