Any

Any contains an arbitrary serialized protocol buffer message along with a URL that describes the type of the serialized message.

Protobuf library provides support to pack/unpack Any values in the form of utility functions or additional generated methods of the Any type.

Example 1: Pack and unpack a message in C++.

Foo foo = ...; Any any; any.PackFrom(foo); ... if (any.UnpackTo(&foo)) { ... }

Example 2: Pack and unpack a message in Java.

Foo foo = ...; Any any = Any.pack(foo); ... if (any.is(Foo.class)) { foo = any.unpack(Foo.class); }

Example 3: Pack and unpack a message in Python.

foo = Foo(...) any = Any() any.Pack(foo) ... if any.Is(Foo.DESCRIPTOR): any.Unpack(foo) ...

Example 4: Pack and unpack a message in Go

foo := &pb.Foo{...}
any, err := ptypes.MarshalAny(foo)
...
foo := &pb.Foo{}
if err := ptypes.UnmarshalAny(any, foo); err != nil {
  ...
}

The pack methods provided by protobuf library will by default use 'type.googleapis.com/full.type.name' as the type URL and the unpack methods only use the fully qualified type name after the last '/' in the type URL, for example "foo.bar.com/x/y.z" will yield type name "y.z".

JSON

The JSON representation of an Any value uses the regular representation of the deserialized, embedded message, with an additional field @type which contains the type URL. Example:

package google.profile; message Person { string first_name = 1; string last_name = 2; }

{ "@type": "type.googleapis.com/google.profile.Person", "firstName": <string>, "lastName": <string> }

If the embedded message type is well-known and has a custom JSON representation, that representation will be embedded adding a field value which holds the custom JSON in addition to the @type field. Example (for message [google.protobuf.Duration][]):

{ "@type": "type.googleapis.com/google.protobuf.Duration", "value": "1.212s" }