Minimum swift hello world server

main.swift

import Network

let myQueue = DispatchQueue(label: "HTTPSimpleServer")
let listener = try! NWListener(using: .tcp, on: 9000)
listener.newConnectionHandler = { ev in
    print("=== new connection ===")

    ev.start(queue: myQueue)
    ev.receive(minimumIncompleteLength: 0, maximumLength: 8096) { content, contentContext, isComplete, error in
        print("=== message recieved ===")

        guard let content else { return }
        guard let parsed = String(data: content, encoding: .utf8) else {
            print("parse error")
            return
        }
        print(parsed)

        let response = """
        HTTP/1.1 200 OK

        Hello

        """
        ev.send(content: response.data(using: .utf8), completion: .contentProcessed({ err in
            ev.cancel()
            print("=== connection canceled ===")
        }))
    }
}

print("Start listening server at http://localhost:9000")
listener.start(queue: myQueue)

print("send return to leave...")
let _ = readLine()