This is the way I initially thought to do it but the extensions seems
like a much better idea. Is there any benefit of using an opaque data
method over extensions.
On Nov 5, 2:15 pm, Jon Parise <j...@booyah.com> wrote:
> Hi Adam,
>
> I needed to do something similar on a previous project. I stored the
> serialized version of the type-specific message as opaque data ("bytes") in
> an outer enveloping message.
>
> message Envelope
> {
> required MsgType type = 1;
> required bytes data = 2;
>
> }
>
> Then you can create any type of message type hierarchy you like. You simply
> write the serialized version of those messages into the 'data' field above
> and switch based on the 'type' field.
>
> There are two immediate downsides to this approach: 1) a few bytes of
> serialization overhead; and 2) the embedded message data is treated
> opaquely, so it's slightly harder to inspect.
>
> — *Jon*
>
>
>
>
>
>
>
> On Fri, Nov 5, 2010 at 10:31 AM, AdamM <adammaga...@gmail.com> wrote:
> > Hello PB Group,
>
> > I am programming a group of programs in C++ that use PB to
> > communicate. In my first version of the program I was using a .proto
> > file that looked similar to the example 1 below. I would then run a
> > switch statement on a MsgType and create the proper message.
>
> > I am now starting to write my second version of the program to include
> > a plugin module architecture. My program calls for a core program and
> > then multiple modules that are written against a base module. Well in
> > my core program I get packets over the network and then parse them
> > info a PB Message.
>
> > I would like a way to have some sort of Base Message that the my core
> > program would use to parse with the base message would contain a
> > packet packet operation code and the data for the actual message
> > structure. I want to program it so the Core program has no idea what
> > the actual message structure is. It would pass it to the respective
> > module based on the operation code who would then parse the actual
> > message structure because it knows what that structure should be.
>
> > Does anyone have any suggestions how to do this? Any help would be
> > much appreciated.
>
> > Example 1.
>
> > enum MsgType {
> > MSG1,
> > MSG2,
> > MSG3
> > }
>
> > Message Msg1 {
> > required int32 field = 1 ;
> > }
>
> > Message Msg2 {
> > required int32 field = 1 ;
> > }
>
> > Message Msg3 {
> > required int32 field = 1 ;
> > }
>
> > Message BaseMessage {
> > required MsgType type = 1 ;
> > optional Msg1 = 2 ;
> > optional Msg2 = 3 ;
> > optional Msg3 = 4 ;
> > }
>
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