Connect Mac/iPhone to a Simple Python Socket Server (iOS Part)

This example shows how to use NSStream to connect an iPhone to a remote Python socket server on a Raspberry Pi. A custom port is used instead of the HTTP port 80.

1. Setup a socket server on a Raspberry Pi:
See Connect Mac/iPhone to a Simple Python Socket Server (Raspberry Pi Part)

The above link also shows how to connect to the socket server from a Mac using telnet and local client python file.

2. Edit ViewController.swift as:

import UIKit

class ViewController: UIViewController, NSStreamDelegate {

    //Button

    var buttonConnect : UIButton!

    

    //Label

    var label : UILabel!

    var labelConnection : UILabel!

    

    //Socket server

    let addr = "192.168.xx.xx"

    let port = 9876

    

    //Network variables

    var inStream : NSInputStream?

    var outStream: NSOutputStream?

    

    //Data received

    var buffer = [UInt8](count: 200, repeatedValue: 0)

    

    override func viewDidLoad() {

        super.viewDidLoad()

        

        ButtonSetup()

        

        LabelSetup()

    }

    

    //Button Functions

    func ButtonSetup() {

        buttonConnect = UIButton(frame: CGRectMake(20, 50, 300, 30))

        buttonConnect.setTitle("Connect to server", forState: UIControlState.Normal)

        buttonConnect.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

        buttonConnect.setTitleColor(UIColor.cyanColor(), forState: UIControlState.Highlighted)

        buttonConnect.addTarget(self, action: "btnConnectPressed:", forControlEvents: UIControlEvents.TouchUpInside)

        view.addSubview(buttonConnect)

        

        let buttoniPhone = UIButton(frame: CGRectMake(20, 100, 300, 30))

        buttoniPhone.setTitle("Send \"This is iPhone\"", forState: UIControlState.Normal)

        buttoniPhone.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

        buttoniPhone.setTitleColor(UIColor.cyanColor(), forState: UIControlState.Highlighted)

        buttoniPhone.addTarget(self, action: "btniPhonePressed:", forControlEvents: UIControlEvents.TouchUpInside)

        view.addSubview(buttoniPhone)

        

        let buttonQuit = UIButton(frame: CGRectMake(20, 150, 300, 30))

        buttonQuit.setTitle("Send \"Quit\"", forState: UIControlState.Normal)

        buttonQuit.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

        buttonQuit.setTitleColor(UIColor.cyanColor(), forState: UIControlState.Highlighted)

        buttonQuit.addTarget(self, action: "btnQuitPressed:", forControlEvents: UIControlEvents.TouchUpInside)

        view.addSubview(buttonQuit)

    }

    

    func btnConnectPressed(sender: UIButton) {

        NetworkEnable()

        

        buttonConnect.alpha = 0.3

        buttonConnect.enabled = false

        buttonConnect.setTitleColor(UIColor.blueColor(), forState: UIControlState.Normal)

    }

    func btniPhonePressed(sender: UIButton) {

        let data : NSData = "This is iPhone".dataUsingEncoding(NSUTF8StringEncoding)!

        outStream?.write(UnsafePointer<UInt8>(data.bytes), maxLength: data.length)

    }

    func btnQuitPressed(sender: UIButton) {

        let data : NSData = "Quit".dataUsingEncoding(NSUTF8StringEncoding)!

        outStream?.write(UnsafePointer<UInt8>(data.bytes), maxLength: data.length)

    }

    //Label setup function

    func LabelSetup() {

        label = UILabel(frame: CGRectMake(0,0,300,150))

        label.center = CGPointMake(view.center.x, view.center.y+100)

        label.textAlignment = NSTextAlignment.Center

        label.numberOfLines = 0 //Multi-lines

        label.font = UIFont(name: "Helvetica-Bold", size: 20)

        view.addSubview(label)

        

        labelConnection = UILabel(frame: CGRectMake(0,0,300,30))

        labelConnection.center = view.center

        labelConnection.textAlignment = NSTextAlignment.Center

        labelConnection.text = "Please connect to server"

        view.addSubview(labelConnection)

    }

    

    //Network functions

    func NetworkEnable() {

        

        print("NetworkEnable")

        NSStream.getStreamsToHostWithName(addr, port: port, inputStream: &inStream, outputStream: &outStream)

        

        inStream?.delegate = self

        outStream?.delegate = self

        

        inStream?.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

        outStream?.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

        

        inStream?.open()

        outStream?.open()

        

        buffer = [UInt8](count: 200, repeatedValue: 0)

    }

    

    func stream(aStream: NSStream, handleEvent eventCode: NSStreamEvent) {

        

        switch eventCode {

        case NSStreamEvent.EndEncountered:

            print("EndEncountered")

            labelConnection.text = "Connection stopped by server"

            inStream?.close()

            inStream?.removeFromRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

            outStream?.close()

            print("Stop outStream currentRunLoop")

            outStream?.removeFromRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

            buttonConnect.alpha = 1

            buttonConnect.enabled = true

        case NSStreamEvent.ErrorOccurred:

            print("ErrorOccurred")

            inStream?.close()

            inStream?.removeFromRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

            outStream?.close()

            outStream?.removeFromRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)

            labelConnection.text = "Failed to connect to server"

            buttonConnect.alpha = 1

            buttonConnect.enabled = true

            label.text = ""

        case NSStreamEvent.HasBytesAvailable:

            print("HasBytesAvailable")

            

            if aStream == inStream {

                inStream!.read(&buffer, maxLength: buffer.count)

                let bufferStr = NSString(bytes: &buffer, length: buffer.count, encoding: NSUTF8StringEncoding)

                label.text = bufferStr! as String

                print(bufferStr!)

            }

            

        case NSStreamEvent.HasSpaceAvailable:

            print("HasSpaceAvailable")

        case NSStreamEvent.None:

            print("None")

        case NSStreamEvent.OpenCompleted:

            print("OpenCompleted")

            labelConnection.text = "Connected to server"

        default:

            print("Unknown")

        }

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

    }

}


3. Enable the socket server on Raspberry Pi and run the iOS simulator on Mac.
Result:

Reference:
Stream Programming Guide
Connect iOS device to HTTP GET/POST PHP service (Raspberry Pi Part) (iOS Part)
Connect iOS device to MySQL database on a server (Raspberry Pi Part) (iOS Part)
Connect Mac/iPhone to a Simple Python Socket Server (Raspberry Pi Part)

Go back to Communication between iOS device (Client) and Raspberry Pi (Server)