I’m working on an addin in C# to generate .proto files based on a UML model in Enterprise Architect.

I’m looking for a way to generate my own .proto files.
I found the FileDescriptorProto from Google.Protobuf.Reflection and I was able to create my own message definition.

// Define message structure
var fileDescriptor = new FileDescriptorProto();
fileDescriptor.Name = "test.proto";
fileDescriptor.Syntax = "proto3";
var message = new DescriptorProto();
message.Name = "TestMessage";
var field1 = new FieldDescriptorProto();
field1.Name = "id";
field1.Type = FieldDescriptorProto.Types.Type.Int32;
//add field to message
message.Field.Add(field1);
//add message to file
fileDescriptor.MessageType.Add(message);

Now unfortunately I don’t seem to find an easy way to write this information to a .proto file.

I tried :

fileDescriptor.WriteTo(new FileStream(filePath, FileMode.OpenOrCreate)); 

But that ended up with a weird

test.proto"
TestMessage
id(bproto3

Converted into hex it looks like this:

0A0A746573742E70726F746F22150A0B
546573744D65737361676512060A0269
642805620670726F746F33

ToString() also didn’t do what I needed as it printed:

{ 
    "name": "test.proto", 
    "messageType": [ { 
        "name": "TestMessage", 
        "field": [ { 
            "name": "id", 
            "type": "TYPE_INT32" 
        } ] 
    } ], 
    "syntax": "proto3" 
}

What I’m expecting is something like

syntax = "proto3";

message TestMessage{
  int32 id = 1;
}