polymorphism - Deserializing a Message multiple times with Google Protocol Buffers -

i working system extremely modular. messages can determined by 3-tuple of src, dest, type.

i'm looking reimplementing our messages protocol buffers. i've read through protocol buffer polymorphism, what's right way polymorphism protocol buffers? , http://www.indelible.org/ink/protobuf-polymorphism/

what wondering has implement solution where:

message header {     required string src = 1     required string dest = 2     required string type = 3 } 

and creating separate messages where:

message foo {     required header h = 1     required string = 2 } 

separate file:

message bar {     required header h = 1     required uint32 num = 2 } 

in receiving code have like:

message.parsefromstring(msgstr) if (message.type == foo) {   foomessage.parsefromstring(msgstr) } else {     barmessage.parsefromstring(msgstr) } 

if approach has been used, better or worse what's described in above links?

only way found serialize/deserialize message body byte array. needed level of abstraction:

message header {     required string src = 1;     required string dest = 2;     required string type = 3; }  message foo {     required string = 2; }  message bar {     required uint32 num = 2; }  message request {     required header h;     required bytes data; // serialize foo or bar here } 

then code (this pseudo-code):

request req = request.parsefromstring(buffer);  if (req.h().type() == "foo") {     foo msg = foo.parsefromstring(req.data);     // process foo msg } else if (req.h().type() == "bar") {     bar msg = bar.parsefromstring(req.data);     // process bar msg }