Find the message Type from Name of the message

[Kiran Kumar]

I have protobuf messages defined as below. I need to find the message type from the attribute name. For example, when the input is "cfgMsg" the output should be ConfigMsg or CfgServerMsg.ConfigMsg (full name).

message CfgServerMsg {
  string name = 1;
  ConfigMsg cfgMsg = 2;
}

message ConfigMsg {
  string cfgName = 1;
  uint32 msgId = 2;
}

I have the below code. However, this is working for well defined types like string, int, float etc. and for messages it just prints "message" as the output.

I removed some code and presented only that is relevant to this question. So this is obviously not the complete code.

google::protobuf::Message *modObj = new ModObj();

const google::protobuf::Descriptor *outModDesc 
            =  modObj->GetDescriptor();
const Reflection *outModRefl = modObj->GetReflection();
const FieldDescriptor *field;

// Loop to iterate over all the fields
{
  field = outModDesc->FindFieldByName(tmp_name);
  std::string type = field->type_name();
  std::cout << "Type:" << type << std::endl;
}

Output: 

Type:string 

Type:message

However, I want to get the actual message type which is "ConfigMsg" instead of just "message". Is there any such API available from protobuf ?

I did check this page https://developers.google.com/protocol-buffers/docs/reference/cpp/google.protobuf.descriptor#FileDescriptor.name.details thoroughly, but couldn't find any thing useful for this.

If anyone has done similar thing or know some thing around this, it would be useful.

Thanks,

[Ilia Mirkin]

You can get the ->message_type() (assuming the ->type() is
TYPE_MESSAGE), which gets you a Descriptor which in turn has a
->name() / ->full_name() function.

Cheers,

-ilia

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[Kiran Kumar]

Thanks. This worked for me. Full code is as below.

outField = outModDesc->FindFieldByName(tmp_name);

const google::protobuf::Descriptor* tmpDesc = outField->message_type();

std::string subMsgType = tmpDesc->name();

std::string subFullMsgType = tmpDesc->full_name();

std::cout << " Type:" << subMsgType

               << "new Type" << newMsgType << std::endl;

                        

Output:

========

Type:ConfigMsg 

Full Type:frrcfg.ConfigMsg

Thanks,

Kiran.

On Tuesday, May 21, 2019 at 4:31:50 PM UTC-7, Ilia Mirkin wrote:

You can get the ->message_type() (assuming the ->type() is
TYPE_MESSAGE), which gets you a Descriptor which in turn has a
->name() / ->full_name() function.

Cheers,

  -ilia

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