// 1. Creat a basic type that can easily hold data.

import Service

public class Storage: Service {
    public var cache: [String: Codable] = [:]

    public init() {}
}

// 2. Register the service as a singleton with the rest of your applications services in `configure`.
// Make sure you set the return type of the closuer!

services.register(isSingleton: true) { (container) -> (Storage) in
    return Storage()
}

// 3. Make it from a request! I created a couple of helper methods for this:

extension Request {
    public func get(_ key: String)throws -> Codable? {
        let storage = try self.privateContainer.make(Storage.self, for: Request.self)
        return storage.cache[key]
    }

    public func set(_ key: String, to value: Codable)throws {
        var storage = try self.privateContainer.make(Storage.self, for: Request.self)
        storage.cache[key] = value
    }
}

// usage:

try request.set("user", to: user)