Example of codeable with nested values without using nested structs

nestedcodable.swift

protocol SOAPElement : Codable {
    static var namespace : String { get }
    static var uri : String { get }
}

protocol WSSEElement : SOAPElement {}

/*
    <wsse:Security>
        <wsse:UsernameToken>
            <wsse:Password>SALIDO</wsse:Password>
            <wsse:Username>SALIDO</wsse:Username>
        </wsse:UsernameToken>
    </wsse:Security>
 */

struct WSSE_BASIC : WSSEElement {
 
    let username : String
    let password : String

    struct UsernameToken : Codable {
        let username : String
        let password : String
    }
    
    static let namespace :String = "wsse"
    static let uri: String = "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"

    enum CodingKeys: String, CodingKey {
        case usernameToken = "wsse:UsernameToken"
    }

    enum UsernameTokenKeys: String, CodingKey {
        case username = "wsse:Username"
        case password = "wsse:Password"
    }
}

extension WSSE_BASIC: Decodable {
    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)

        let usernameToken = try values.nestedContainer(keyedBy: UsernameTokenKeys.self, forKey: .usernameToken)
        username = try usernameToken.decode(String.self, forKey: .username)
        password = try usernameToken.decode(String.self, forKey: .password)
    }
}

extension WSSE_BASIC: Encodable {
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        
        var usernameToken = container.nestedContainer(keyedBy: UsernameTokenKeys.self, forKey: .usernameToken)
        try usernameToken.encode(username, forKey: .username)
        try usernameToken.encode(password, forKey: .password)
    }
}