Document how to parse a .proto into a ProtoFile instance

[vorburger]

I got to this project via the now archived https://github.com/square/protoparser (which is a top hit when searching something like "proto parser in java"), from here for this, and am wondering (and starting to dig around the code...) to try to figure how exactly to use wire-schema in this project to parse a .proto into a ProtoFile instance?

Perhaps the README of this project, and/or of the old square/protoparser, could include a link to a simple test/example which illustrates this?

[oldergod]

You can use SchemaLoader. Add your roots and call loadSchema. You'll get a Schema object which will have all info.

If you don't need metadata or type resolution, you can use ProtoParser.parse()

[jmini]

In case somebody finds this discussion, some more details:

wire is a Kotlin multi-platform library, so to use it in a java application, you need the wire-schema-jvm library (and not just wire-schema):

com.squareup.wire:wire-schema-jvm:4.9.3

Example code:

import java.nio.file.FileSystems;
import java.util.List;

import com.squareup.wire.schema.Field;
import com.squareup.wire.schema.Location;
import com.squareup.wire.schema.MessageType;
import com.squareup.wire.schema.ProtoFile;
import com.squareup.wire.schema.Schema;
import com.squareup.wire.schema.SchemaLoader;
import com.squareup.wire.schema.Type;

public class ExampleMain {

    public static void main(String[] args) {
        SchemaLoader loader = new SchemaLoader(FileSystems.getDefault());
        List<Location> sourcePath = List.of(Location.get("/<path to project>/src/main/proto"));
        List<Location> protoPath = List.of();
        loader.initRoots(sourcePath, protoPath);
        Schema schema = loader.loadSchema();
        List<ProtoFile> protoFiles = schema.getProtoFiles();
        for (ProtoFile protoFile : protoFiles) {
            System.out.println(protoFile);
        }
        Type type = schema.getType("com.company.Address");
        if (type instanceof MessageType) {
            MessageType messageType = (MessageType) type;
            for (Field f : messageType.getDeclaredFields()) {
                System.out.println(f);
            }
        }
    }
}

[MPeli]

Hi, I've successfully parsed a proto file and now have instances of ProtoFile and a protobuf. How can I deserialize a message using ProtoFile? I'm specifically interested in obtaining a JSON string as output. Thank you.