TL;DR : What's the way to check if my remote stream are opened correctly after a call to
NSStream.getStreamsToHostWithName(...)
?
My application is a mobile IOS8 swift application.
I am using NSStream for input and output socket communication with a remote server.
To connect to my server and open my stream I use this code:
func connect(host: String, port: Int) -> Bool
{
//clear the previous connection if existing (and update self.connected)
disconnect()
//updating the current connection
self.host = host
self.port = port
//pairing NSstreams with remote connection
NSStream.getStreamsToHostWithName(self.host!, port: self.port!, inputStream: &inputStream, outputStream: &outputStream)
if (self.inputStream != nil && self.outputStream != nil)
{
//open streams
self.inputStream?.open()
self.outputStream?.open()
}
if self.outputStream?.streamError == nil && self.inputStream?.streamError == nil
{
println("SOK") //PROBLEM 1
}
//error checking after opening streams // PROBLEM 2
if var inputStreamErr: CFError = CFReadStreamCopyError(self.inputStream)?
{
println("InputStream error : " + CFErrorCopyDescription(inputStreamErr))
}
else if var outputStreamErr: CFError = CFWriteStreamCopyError(self.outputStream)?
{
println("OutStream error : " + CFErrorCopyDescription(outputStreamErr))
}
else
{
//set the delegate to self
self.inputStream?.delegate = self
self.outputStream?.delegate = self
self.connected = true
}
//return connection state
return self.connected
}
My problem is located at //PROBLEM1 and //PROBLEM2.
At these points I try to determine if my sockets are opened correctly, but even if the server is not running this code still works, then the read and write operations are failing. I would like to be able to determine if the connection failed or not.
Maybe I am doing it totally wrong, I don't get how to test this.
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)