Routing Problem

Routing.swift

import Foundation

struct Handler {
    let handleJSON: (Data) throws -> Void
    
    init<T: Decodable>(handler: @escaping (T) -> Void) {
        handleJSON = { data in
            let object = try JSONDecoder().decode(T.self, from: data)
            handler(object)
        }
    }
}

// Here's where I set up the (simplified) routing aka try to store functions in a dictionary keyed by "endpoints":
var handlers = [String: Handler]()

func register<T: Decodable>(
    endpoint: String,
    with handle: @escaping (T) -> Void)
{
    handlers[endpoint] = Handler(handler: handle)
}

register(endpoint: "hello") { (object: String) in
    print("got a string: \(object)")
}

// Here's what I'd like to do once I have data and know the endpoint:
func didReceive(data: Data, for endpoint: String) throws {
    guard let handler = handlers[endpoint] else { return }
    try handler.handleJSON(data)
}

struct Person: Codable {
    let name: String
    let age: Int
}

register(endpoint: "person", with: { (p: Person) in
    dump(p)
})

try didReceive(data: try! JSONEncoder().encode(Person(name: "Foo", age: 99)), for: "person")