NWConnection not establishing WebSocket Connection, Why ?!

Question

Vinz1911 OP

Created Feb ’21

Replies 1

Boosts 0

Views 1.9k

Participants 2

Hi Guy's

I have trouble creating a WebSocket based Connection by using direct Network.framework's NWConnection.

And I don't want to use URLSessions Way!

I Watched the Apple Keynote and it's not working for me.
I'm trying to connect to a public WebSocket Echo Server.

I put the code in a simple playground. Maybe some of you can light me up and explain what is wrong here 'cause i'm not seeing any issue ?!

Thanks and best regards
Vinz

Code Block swiftimport UIKit
import Network
import PlaygroundSupport
let parameters = NWParameters.tls
let options = NWProtocolWebSocket.Options()
parameters.defaultProtocolStack.applicationProtocols.insert(options, at: 0)
let connection = NWConnection(host: .init("wss://echo.websocket.org/"), port: .https, using: parameters)
connection.stateUpdateHandler = { state in
    switch state {
    case .ready:
        print("connection ready")
    case .failed(let error):
        print("connection failed with:", error)
    default:
        break
    }
}
print("start")
connection.start(queue: .main)
PlaygroundPage.current.needsIndefiniteExecution = true

Answered by DTS Engineer in 662956022

If you insert this:

Code Block  print(state)

at line 13 you’ll see that it prints:

Code Block  preparing
waiting(-65554: NoSuchRecord)

The connection is waiting for DNS to be able to resolve the host you supplied. Clearly echo.websocket.org is correct, so something else is wonky.

The issue here is that you’re constructing your NWConnection with a host and port. This doesn’t work for WebSocket; you need to give it a URL. You do that by replacing line 9 with this:

Code Block  let url = URL(string: "wss://echo.websocket.org/")!
let connection = NWConnection(to: .url(url), using: parameters)

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@apple.com"

Boost

Answer 1

DTS Engineer OP

Apple

Feb ’21

Accepted Answer

If you insert this:

Code Block  print(state)

at line 13 you’ll see that it prints:

Code Block  preparing
waiting(-65554: NoSuchRecord)

The connection is waiting for DNS to be able to resolve the host you supplied. Clearly echo.websocket.org is correct, so something else is wonky.

The issue here is that you’re constructing your NWConnection with a host and port. This doesn’t work for WebSocket; you need to give it a URL. You do that by replacing line 9 with this:

Code Block  let url = URL(string: "wss://echo.websocket.org/")!
let connection = NWConnection(to: .url(url), using: parameters)

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@apple.com"

2