How to test if my remote socket NSStream are correctly open

Question

TL;DR : What\'s the way to check if my remote stream are opened correctly after a call to NSStream.getStreamsToHostWithName(...)?

Answer 1

First of all, you have to schedule the stream on a runloop:

inputStream!.scheduleInRunLoop(.mainRunLoop(), forMode: NSDefaultRunLoopMode)
outputStream!.scheduleInRunLoop(.mainRunLoop(), forMode: NSDefaultRunLoopMode)

And, in your code, it's too soon to check the error. Because open() is async operation, you have to wait the result using delegate. Here is working example:

import Foundation

class Connection: NSObject, NSStreamDelegate {
var host:String?
var port:Int?
var inputStream: NSInputStream?
var outputStream: NSOutputStream?

func connect(host: String, port: Int) {

    self.host = host
    self.port = port

    NSStream.getStreamsToHostWithName(host, port: port, inputStream: &inputStream, outputStream: &outputStream)

    if inputStream != nil && outputStream != nil {

        // Set delegate
        inputStream!.delegate = self
        outputStream!.delegate = self

        // Schedule
        inputStream!.scheduleInRunLoop(.mainRunLoop(), forMode: NSDefaultRunLoopMode)
        outputStream!.scheduleInRunLoop(.mainRunLoop(), forMode: NSDefaultRunLoopMode)

        print("Start open()")

        // Open!
        inputStream!.open()
        outputStream!.open()
    }
}

func stream(aStream: NSStream, handleEvent eventCode: NSStreamEvent) {
    if aStream === inputStream {
        switch eventCode {
        case NSStreamEvent.ErrorOccurred:
            print("input: ErrorOccurred: \(aStream.streamError?.description)")
        case NSStreamEvent.OpenCompleted:
            print("input: OpenCompleted")
        case NSStreamEvent.HasBytesAvailable:
            print("input: HasBytesAvailable")

            // Here you can `read()` from `inputStream`

        default:
            break
        }
    }
    else if aStream === outputStream {
        switch eventCode {
        case NSStreamEvent.ErrorOccurred:
            print("output: ErrorOccurred: \(aStream.streamError?.description)")
        case NSStreamEvent.OpenCompleted:
            print("output: OpenCompleted")
        case NSStreamEvent.HasSpaceAvailable:
            print("output: HasSpaceAvailable")

            // Here you can write() to `outputStream`

        default:
            break
        }
    }
}

}

Then:

let conn = Connection()
conn.connect("www.example.com", port: 80)