Starscream: Can't get Starscream to work in a simple command-line app

Created on 25 Sep 2016 · 4Comments · Source: daltoniam/Starscream

I am playing with a simple command-line app:

$ swift package init --type=executable

After adding Starscream as a dependency, I added the following code in main.swift

import Foundation
import Starscream

let echoURL = URL(string: "ws://echo.websocket.org/")!

class WsClient: WebSocketDelegate {
    let socket: WebSocket

    init() {
        socket = WebSocket(url: echoURL)
        socket.delegate = self
    }

    func connect() {
        print("Connecting")
        socket.connect()
    }

    func websocketDidConnect(socket: WebSocket) {
        print("Connected")
        socket.write(string: "test") {
            print("Sent")
        }
    }

    func websocketDidReceiveData(socket: WebSocket, data: Data) {    
    }

    func websocketDidDisconnect(socket: WebSocket, error: NSError?) {
        print("Disconnect")
        print(error)
    }

    func websocketDidReceiveMessage(socket: WebSocket, text: String) {
    }
}

let client = WsClient()
client.connect()

sleep(10)

I build the app and run it.

$ swift build
$ ./build/.../TestApp

However the delegate methods are not called, i.e. I see "Connecting" printed but not "Connected" (or "Disconnected".

Any help appreciated.

PS: I am running on latest macOS with Swift 3.0

Source

gmosx

Most helpful comment

Full code for clarity:

import Foundation
import Starscream

let echoURL = URL(string: "ws://echo.websocket.org/")!

class WsClient: WebSocketDelegate {
    let socket: WebSocket

    init() {
        socket = WebSocket(url: echoURL)
        socket.delegate = self
    }

    func connect() {
        print("Connecting")
        socket.connect()
    }

    func websocketDidConnect(socket: WebSocket) {
        print("Connected")
        socket.write(string: "test") {
            print("Sent")
        }
    }

    func websocketDidReceiveData(socket: WebSocket, data: Data) {
    }

    func websocketDidDisconnect(socket: WebSocket, error: NSError?) {
        print("Disconnect")
        print(error)
    }

    func websocketDidReceiveMessage(socket: WebSocket, text: String) {
        print("Got: \(text)")
    }
}

let client = WsClient()
client.connect()

while(true) {
    RunLoop.current.run(until: Date())
    usleep(10)
}

daltoniam on 26 Sep 2016

👍4

All 4 comments

The issue is using sleep. That blocks the main runloop from processing any of the delegate request that come back to it. Change the sleep to:

while(true) {
    RunLoop.current.run(until: Date())
    usleep(10)
}

This will achieve the "blocking" and keep the app from closing right on start, but still allow the runloop to process delegate callbacks.

daltoniam on 26 Sep 2016

Full code for clarity:

import Foundation
import Starscream

let echoURL = URL(string: "ws://echo.websocket.org/")!

class WsClient: WebSocketDelegate {
    let socket: WebSocket

    init() {
        socket = WebSocket(url: echoURL)
        socket.delegate = self
    }

    func connect() {
        print("Connecting")
        socket.connect()
    }

    func websocketDidConnect(socket: WebSocket) {
        print("Connected")
        socket.write(string: "test") {
            print("Sent")
        }
    }

    func websocketDidReceiveData(socket: WebSocket, data: Data) {
    }

    func websocketDidDisconnect(socket: WebSocket, error: NSError?) {
        print("Disconnect")
        print(error)
    }

    func websocketDidReceiveMessage(socket: WebSocket, text: String) {
        print("Got: \(text)")
    }
}

let client = WsClient()
client.connect()

while(true) {
    RunLoop.current.run(until: Date())
    usleep(10)
}

daltoniam on 26 Sep 2016

👍4

Duh!

Working with single-threaded languages for a long-time does this to you :)

Thank you!

On Mon, Sep 26, 2016 at 7:47 AM Dalton [email protected] wrote:

Closed #254 https://github.com/daltoniam/Starscream/issues/254.

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gmosx on 26 Sep 2016

@gmosx how did you get around missing dynamic link refs when building and running the executable? I'm getting these issues, and I believe it's because Swift has no good way of dealing with dynamic frameworks for commandline apps. Coacocapods introduced a way to specify a framework as static, but Starscream doesn't appear to conform in its Podspec

https://github.com/CocoaPods/CocoaPods/pull/6811