1// Go support for Protocol Buffers - Google's data interchange format 2// 3// Copyright 2016 The Go Authors. All rights reserved. 4// https://github.com/golang/protobuf 5// 6// Redistribution and use in source and binary forms, with or without 7// modification, are permitted provided that the following conditions are 8// met: 9// 10// * Redistributions of source code must retain the above copyright 11// notice, this list of conditions and the following disclaimer. 12// * Redistributions in binary form must reproduce the above 13// copyright notice, this list of conditions and the following disclaimer 14// in the documentation and/or other materials provided with the 15// distribution. 16// * Neither the name of Google Inc. nor the names of its 17// contributors may be used to endorse or promote products derived from 18// this software without specific prior written permission. 19// 20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 32package ptypes 33 34// This file implements functions to marshal proto.Message to/from 35// google.protobuf.Any message. 36 37import ( 38 "fmt" 39 "reflect" 40 "strings" 41 42 "github.com/golang/protobuf/proto" 43 "github.com/golang/protobuf/ptypes/any" 44) 45 46const googleApis = "type.googleapis.com/" 47 48// AnyMessageName returns the name of the message contained in a google.protobuf.Any message. 49// 50// Note that regular type assertions should be done using the Is 51// function. AnyMessageName is provided for less common use cases like filtering a 52// sequence of Any messages based on a set of allowed message type names. 53func AnyMessageName(any *any.Any) (string, error) { 54 if any == nil { 55 return "", fmt.Errorf("message is nil") 56 } 57 slash := strings.LastIndex(any.TypeUrl, "/") 58 if slash < 0 { 59 return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl) 60 } 61 return any.TypeUrl[slash+1:], nil 62} 63 64// MarshalAny takes the protocol buffer and encodes it into google.protobuf.Any. 65func MarshalAny(pb proto.Message) (*any.Any, error) { 66 value, err := proto.Marshal(pb) 67 if err != nil { 68 return nil, err 69 } 70 return &any.Any{TypeUrl: googleApis + proto.MessageName(pb), Value: value}, nil 71} 72 73// DynamicAny is a value that can be passed to UnmarshalAny to automatically 74// allocate a proto.Message for the type specified in a google.protobuf.Any 75// message. The allocated message is stored in the embedded proto.Message. 76// 77// Example: 78// 79// var x ptypes.DynamicAny 80// if err := ptypes.UnmarshalAny(a, &x); err != nil { ... } 81// fmt.Printf("unmarshaled message: %v", x.Message) 82type DynamicAny struct { 83 proto.Message 84} 85 86// Empty returns a new proto.Message of the type specified in a 87// google.protobuf.Any message. It returns an error if corresponding message 88// type isn't linked in. 89func Empty(any *any.Any) (proto.Message, error) { 90 aname, err := AnyMessageName(any) 91 if err != nil { 92 return nil, err 93 } 94 95 t := proto.MessageType(aname) 96 if t == nil { 97 return nil, fmt.Errorf("any: message type %q isn't linked in", aname) 98 } 99 return reflect.New(t.Elem()).Interface().(proto.Message), nil 100} 101 102// UnmarshalAny parses the protocol buffer representation in a google.protobuf.Any 103// message and places the decoded result in pb. It returns an error if type of 104// contents of Any message does not match type of pb message. 105// 106// pb can be a proto.Message, or a *DynamicAny. 107func UnmarshalAny(any *any.Any, pb proto.Message) error { 108 if d, ok := pb.(*DynamicAny); ok { 109 if d.Message == nil { 110 var err error 111 d.Message, err = Empty(any) 112 if err != nil { 113 return err 114 } 115 } 116 return UnmarshalAny(any, d.Message) 117 } 118 119 aname, err := AnyMessageName(any) 120 if err != nil { 121 return err 122 } 123 124 mname := proto.MessageName(pb) 125 if aname != mname { 126 return fmt.Errorf("mismatched message type: got %q want %q", aname, mname) 127 } 128 return proto.Unmarshal(any.Value, pb) 129} 130 131// Is returns true if any value contains a given message type. 132func Is(any *any.Any, pb proto.Message) bool { 133 // The following is equivalent to AnyMessageName(any) == proto.MessageName(pb), 134 // but it avoids scanning TypeUrl for the slash. 135 if any == nil { 136 return false 137 } 138 name := proto.MessageName(pb) 139 prefix := len(any.TypeUrl) - len(name) 140 return prefix >= 1 && any.TypeUrl[prefix-1] == '/' && any.TypeUrl[prefix:] == name 141} 142