Custom Serializers

For types that cannot or should not use @ForyObject, implement Serializer manually.

When to Use Custom Serializers

• External types with strict wire compatibility requirements
• Specialized compact encodings
• Legacy payload migration paths
• Highly tuned hot-path serialization

Implementing Serializer

import Foundation
import Fory

struct UUIDBox: Serializer, Equatable {
    var value: UUID = UUID(uuidString: "00000000-0000-0000-0000-000000000000")!

    static func foryDefault() -> UUIDBox {
        UUIDBox()
    }

    static var staticTypeId: ForyTypeId {
        .ext
    }

    func foryWriteData(_ context: WriteContext, hasGenerics: Bool) throws {
        _ = hasGenerics
        try value.uuidString.foryWriteData(context, hasGenerics: false)
    }

    static func foryReadData(_ context: ReadContext) throws -> UUIDBox {
        let raw = try String.foryReadData(context)
        guard let uuid = UUID(uuidString: raw) else {
            throw ForyError.invalidData("invalid UUID string: \(raw)")
        }
        return UUIDBox(value: uuid)
    }
}

Register and Use

let fory = Fory()
fory.register(UUIDBox.self, id: 300)

let input = UUIDBox(value: UUID())
let data = try fory.serialize(input)
let output: UUIDBox = try fory.deserialize(data)

assert(input == output)

Choosing staticTypeId

For manually implemented custom types, use staticTypeId that matches the wire kind you are implementing.

Typical choices:

• .structType: regular structured object
• .enumType / .typedUnion: enum-like values
• .ext: extension/custom kind