Manually encode and decode a codable type to and from a bytebuffer for redis usage

bytebuffer-serialization.swift

import Vapor
import RedisKit

struct MySession {
    let token: RedisKey
    
    let email: String
    let userId: Int64
    let isAdmin: Bool
    let ipAddress: String?
    
    func encode(into buffer: inout ByteBuffer) {
        buffer.writeInteger(UInt16(email.count), as: UInt16.self)
        buffer.writeString(email)
        buffer.writeInteger(userId, as: Int64.self)
        buffer.writeInteger(isAdmin ? 1 : 0, as: UInt8.self)
        if let ip = ipAddress {
            buffer.writeInteger(1, as: UInt8.self)
            buffer.writeString(ip)
        } else {
            buffer.writeInteger(0, as: UInt8.self)
        }
    }
    
    static func decode(from buffer: inout ByteBuffer, token: String) -> MySession? {
        guard
            let emailLength = buffer.readInteger(as: UInt16.self),
            let email = buffer.readString(length: Int(emailLength)),
            let userId = buffer.readInteger(as: Int64.self),
            let isAdmin = buffer.readInteger(as: UInt8.self),
            let hasIp = buffer.readInteger(as: UInt8.self)
        else { return nil }
        
        let ipAddress = hasIp == 1 ? buffer.readString(length: buffer.readableBytes) : nil
        return MySession(
            token: RedisKey(token),
            email: email,
            userId: userId,
            isAdmin: isAdmin == 1 ? true : false,
            ipAddress: ipAddress
        )
    }
    
}