1 // Go support for Protocol Buffers - Google's data interchange format
3 // Copyright 2016 The Go Authors. All rights reserved.
4 // https://github.com/golang/protobuf
6 // Redistribution and use in source and binary forms, with or without
7 // modification, are permitted provided that the following conditions are
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
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.
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
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30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 // This file implements functions to marshal proto.Message to/from
35 // google.protobuf.Any message.
42 "github.com/golang/protobuf/proto"
43 "github.com/golang/protobuf/ptypes/any"
46 const googleApis = "type.googleapis.com/"
48 // AnyMessageName returns the name of the message contained in a google.protobuf.Any message.
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.
53 func AnyMessageName(any *any.Any) (string, error) {
55 return "", fmt.Errorf("message is nil")
57 slash := strings.LastIndex(any.TypeUrl, "/")
59 return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl)
61 return any.TypeUrl[slash+1:], nil
64 // MarshalAny takes the protocol buffer and encodes it into google.protobuf.Any.
65 func MarshalAny(pb proto.Message) (*any.Any, error) {
66 value, err := proto.Marshal(pb)
70 return &any.Any{TypeUrl: googleApis + proto.MessageName(pb), Value: value}, nil
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.
79 // var x ptypes.DynamicAny
80 // if err := ptypes.UnmarshalAny(a, &x); err != nil { ... }
81 // fmt.Printf("unmarshaled message: %v", x.Message)
82 type DynamicAny struct {
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.
89 func Empty(any *any.Any) (proto.Message, error) {
90 aname, err := AnyMessageName(any)
95 t := proto.MessageType(aname)
97 return nil, fmt.Errorf("any: message type %q isn't linked in", aname)
99 return reflect.New(t.Elem()).Interface().(proto.Message), nil
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.
106 // pb can be a proto.Message, or a *DynamicAny.
107 func UnmarshalAny(any *any.Any, pb proto.Message) error {
108 if d, ok := pb.(*DynamicAny); ok {
109 if d.Message == nil {
111 d.Message, err = Empty(any)
116 return UnmarshalAny(any, d.Message)
119 aname, err := AnyMessageName(any)
124 mname := proto.MessageName(pb)
126 return fmt.Errorf("mismatched message type: got %q want %q", aname, mname)
128 return proto.Unmarshal(any.Value, pb)
131 // Is returns true if any value contains a given message type.
132 func Is(any *any.Any, pb proto.Message) bool {
133 aname, err := AnyMessageName(any)
138 return aname == proto.MessageName(pb)