The lib is not considered as stable and an API might be broken until v1.x.x version is tagged.
This lib provides some utils to work with protobuf messages together with MongoDB.
Main reason to create this package is a protojson
package that encodes proto messages differently than an encodying/json package. This creates a big gap between
regular golang structs and structs provided by a protoc.
This package is highly inspired by the original protojson package but bound to the go.mongodb.org/mongo-driver
package.
The package provides codecs and a registry that compatible with the mongo-dirver and fits well into the mongo-driver
encode/decode process. The codec designed mostly as intermediate component who can encode and decode the proto.Message
and leverage the mongo-driver registry machinery to encode or decode primitive types and lists/maps.
Only special case is enums. Enums cannot be properly decoded because in protoreflect they represented as
the protoreflect.EnumNumber which completely loose an original enum type, so when we encode or decode an enum value
represented as string we cannot guess which enum we currently encode or decode.
To solve this we have two ways:
- Embed the enum codec into the
ProtoMessageCodec. - Implement the
ProtoEnumCodecand introduce special handling of the enum values in theProtoMessageCodec
In the protojson package implemented second solution. It decouple encode and decode of enums from
the ProtoMessageCodec. But still introduce pretty ugly way to operate with enum fields in the message.
If you use a default registry from mongo-driver you can just overwrite it in client — registry provided by
the protobson.BsonPBRegistry should be equal to default one, just with special hooks that will handle protobuf models.
If you customize your registry — you should read the registry.go file and see how you can
add required codecs into registry.
Partially implemented with some caveats. To see details - go to README in protobson/types package.