Is there a lifecycle hook for reading a Fluent model?

Related Projects Vapor
1

I have a database table called foos which has two fields, id and protobuf_data.

    return database.schema("foos")
      .id()
      .field("protobuf_data", .data, .required)
      .create()

The protobuf_data contains the serialized bytes from a protobuf struct, called Bar. I have defined the Foo model class like so:

final class Foo: Model {
  static let schema = "foos"

  @ID(key: .id)
  var id: UUID?

  // Holds the serialized bytes for the Bar protobuf
  @Field(key: "protobuf_data")
  var protobufData: Data 

  // Deserialized instance from the bytes stored in protobufData
  var bar: Bar
}

I am using a custom ModelMiddleware to serialize the Bar instance and assign the bytes to protobufData. My question is how can I hook into when a model is read from the database so that I can deserialize the bytes and assign the Bar instance to the my variable?

Note: I am aware of being able to store arbitrary dictionaries to do something similar. However, I would like the serialized format to be protobuf.

Any help or pointers would be greatly appreciated.

2

There aren't any hooks for that built into Fluent. You could override the decoding properties for the model which would have the same effect (or use a custom property wrapper)

3

I will give that a try. Thanks for the suggestion.