For anyone who stumbles upon this...
The code reference is here
<https://github.com/protocolbuffers/protobuf/tree/master/ruby/src/main/java/com/google/protobuf/jruby>.
Most classes do not have public methods to instantiate them in Ruby, so
creating new protos programmatically doesn't seem possible.
But it's possible to traverse a proto programmatically and get all the
fields and types:
```
class TraverseDescriptor
def get_all_fields(klass)
if !klass.respond_to?(:descriptor)
puts "The provided class doesn't have a descriptor!"
return
end
klass.descriptor.each do |n|
puts("#{klass.descriptor.name}: #{n.label}, #{n.name}, #{n.type}")
if n.type == :message
msg_class = n.subtype.msgclass.descriptor.name
get_all_fields(::Google::Protobuf::DescriptorPool.generated_pool.lookup(
msg_class).msgclass)
end
end
end
end
```
To run: # bundle exec ruby -e "require '<path_to_pb>'; require
'./traverse_descriptor';
TraverseDescriptor.new.get_all_fields(Tutorial::AddressBook)"
On Friday, October 22, 2021 at 5:20:50 PM UTC-7 Shine Garg wrote:
> I'd like to leverage this
> <https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/descriptor.proto#L36-L37>
> to
> read a `.proto` file *in Ruby* and get a handle on the underlying
> `FileDescriptorProto` to do some validations. But it's not clear to me how
> to read the proto file into this object.
>
> I tried to read both the .proto file as well as the output of the
> `--descriptor_set_out`. Any guidance would be appreciated.
>
> In bundle console:
>
> // output of --descriptor_set_out dumped to set.txt
> 2.6.3 :114 > fl = File.open("<full path to/set.txt>", "r")
> => #<File:/path/to/set.txt>
>
> 2.6.3 :115 > Google::Protobuf::FileDescriptor.new(file: fl, package:
> "tutorial")
> Traceback (most recent call last):
> 16: from ~/.rvm/gems/ruby-2.6.3/bin/bundle:23:in `<main>'
> 15: from ~/.rvm/gems/ruby-2.6.3/bin/bundle:23:in `load'
> 14: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/gems/2.6.0/gems/bundler-1.17.3/exe/bundle:22:in
>
> `<top (required)>'
> 13: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/friendly_errors.rb:124:in
>
> `with_friendly_errors'
> 12: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/gems/2.6.0/gems/bundler-1.17.3/exe/bundle:30:in
>
> `block in <top (required)>'
> 11: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/cli.rb:18:in
> `start'
> 10: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/vendor/thor/lib/thor/base.rb:466:in
>
> `start'
> 9: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/cli.rb:27:in
> `dispatch'
> 8: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/vendor/thor/lib/thor.rb:387:in
>
> `dispatch'
> 7: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/vendor/thor/lib/thor/invocation.rb:126:in
>
> `invoke_command'
> 6: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/vendor/thor/lib/thor/command.rb:27:in
>
> `run'
> 5: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/cli.rb:494:in
> `console'
> 4: from
> ~/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0/bundler/cli/console.rb:19:in
>
> `run'
> 3: from (irb):115
> 2: from (irb):115:in `new'
> 1: from (irb):115:in `initialize'
> ArgumentError (wrong number of arguments (given 1, expected 3))
>
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