How to convert Ruby protobuf Message to JSON while preserving the case used in the proto? - ruby

Question

When you convert a Protobuf Message in Ruby to JSON using to_json it converts all fieldnames to camelCase.
e.g. with protobuf message Person as
message Person {
string name = 1;
int32 id = 2;
string email_address = 3;
and Person in Ruby as
person = Person.new(:name => "Bob",
:id => 1,
:email_address => "foo#bar.com")
Serialized to JSON
person.to_json
>>> {"name":"Bob","id":"1","emailAddress":"foo#bar.com"}
the field email_address gets serialized in camelCase instead of snake case as it is in the proto
How can you serialize it with the original proto fieldnames?
I tried converting it to a Ruby Hash (with .to_h) at first since it preserves field names, but ran into a different issue. Fields with double values will be rendered as a Hash like price: {"value": 10.0"} instead of price: 10.0.

Answer 1

Buried deep in the source code is the answer.
There is an option in to_json to preserve the case used in the proto by passing in preserve_proto_fieldnames: true
e.g. person.to_json({preserve_proto_fieldnames: true})
Unfortunately this doesn't seem to be elsewhere in the Ruby protobuf documentation