Send String and NSData at the same time over peer to peer?

Question

I am adding text fields which are of type (String) and an image which is of type (NSData) to a dictionary sending it to a peer, and on the other side it is decoding the dictionary in to a Strings with key value pairs.

The image data in the dictionary is no longer NSData but a string. How would I send the string and data at the same time and retrieve it as a string and data?

import MultipeerConnectivity
import UIKit


class ViewController: UIViewController, MCSessionDelegate, MCBrowserViewControllerDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

var browser : MCBrowserViewController!
var assistant : MCAdvertiserAssistant!
var session : MCSession!
var peerID: MCPeerID!

var firstNameVar = ""
var lastNameVar = ""
var imageDataVar: NSData!

let imagePicker  = UIImagePickerController()
var tapGestureID = Int()

@IBOutlet weak var firstLame: UITextField!
@IBOutlet weak var lastName: UITextField!
@IBOutlet weak var firstNameLabel: UILabel!
@IBOutlet weak var lastNameLabel: UILabel!
@IBOutlet weak var contactImage: UIImageView!

@IBAction func showBrowser(sender: UIButton) {
    self.presentViewController(self.browser, animated: true, completion: nil)
}

@IBAction func getImage(sender: AnyObject) {
    chooseImageContact()
}

@IBAction func sendChat(sender: AnyObject) {
    sendInfo()
}

override func viewDidLoad() {
    super.viewDidLoad()
    self.peerID = MCPeerID(displayName: UIDevice.currentDevice().name)

    //self.session = MCSession(peer: peerID, securityIdentity: nil, encryptionPreference: .Required)
    self.session = MCSession(peer: self.peerID)
    self.session.delegate = self

    // create the browser viewcontroller with a unique service name
    self.browser = MCBrowserViewController(serviceType: "LCOC-Chat", session: self.session)
    self.browser.delegate = self

    // tell the assistant to start advertising our fabulous chat
    self.assistant = MCAdvertiserAssistant(serviceType:"LCOC-Chat", discoveryInfo:nil, session:self.session)
    self.assistant.start()
}

func sendInfo() {
    if self.session.connectedPeers.count > 0 {
        firstNameVar = firstLame.text!
        lastNameVar = lastName.text!
        let myDictionary = ["itemA" : "\(firstNameVar)", "itemB" : "\(lastNameVar)", "itemC" : "\(imageDataVar)"]
        do {
        let data =  NSKeyedArchiver.archivedDataWithRootObject(myDictionary)
        try self.session.sendData(data, toPeers: self.session.connectedPeers, withMode: MCSessionSendDataMode.Unreliable)
        } catch let error as NSError {
                let ac = UIAlertController(title: "Send error", message: error.localizedDescription, preferredStyle: .Alert)
                    ac.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
                    presentViewController(ac, animated: true, completion: nil)
            }
    }
    self.firstLame.text = ""
    self.lastName.text = ""
}


// Called when a peer sends an NSData to us
func session(session: MCSession, didReceiveData data: NSData, fromPeer peerID: MCPeerID) {

     // This needs to run on the main queue
    dispatch_async(dispatch_get_main_queue()) {
    let myDictionary = NSKeyedUnarchiver.unarchiveObjectWithData(data) as! NSDictionary
        self.firstNameLabel.text = myDictionary.valueForKey("itemA") as? String
        self.lastNameLabel.text = myDictionary.valueForKey("itemB") as? String

//            self.firstNameVar = myDictionary.valueForKey("itemA") as? String
//            self.lastNameVar = myDictionary.valueForKey("itemB") as? String
//            let image = myDictionary.valueForKey("itemC") as? String
//            let imageData = NSKeyedUnarchiver.unarchiveObjectWithData(image) as? NSData

    }
}

func browserViewControllerDidFinish(browserViewController: MCBrowserViewController) {
    dismissViewControllerAnimated(true, completion: nil)
}
func browserViewControllerWasCancelled(browserViewController: MCBrowserViewController) {
    dismissViewControllerAnimated(true, completion: nil)
}
func browserViewController(browserViewController: MCBrowserViewController, shouldPresentNearbyPeer peerID: MCPeerID, withDiscoveryInfo info: [String : String]?) -> Bool {
    return true
}

func session(session: MCSession, peer peerID: MCPeerID, didChangeState state: MCSessionState) {
    switch state {
    case MCSessionState.Connected:
        print("Connected: \(peerID.displayName)")
    case MCSessionState.Connecting:
        print("Connecting: \(peerID.displayName)")
    case MCSessionState.NotConnected:
        print("Not Connected: \(peerID.displayName)")
    }
}

func session(session: MCSession, didStartReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, withProgress progress: NSProgress) {
}
func session(session: MCSession, didFinishReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, atURL localURL: NSURL, withError error: NSError?) {
}
func session(session: MCSession, didReceiveStream stream: NSInputStream, withName streamName: String, fromPeer peerID: MCPeerID) {
}

func textFieldShouldReturn(textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
}


// Picking the image
func chooseImageContact(){
    let imagePicker        = UIImagePickerController()
    imagePicker.delegate   = self
    imagePicker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
    self.presentViewController(imagePicker, animated: true, completion: nil)
}

//Scalling the image
func scaleContactImageWith(image:UIImage, newSize:CGSize)->UIImage{
    UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
    image.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
    let newContactImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return newContactImage
}

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
    //This gets the Contact image inside the imagePickerController
        let pickedImage:UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage
        let smallPicture        = scaleContactImageWith(pickedImage, newSize: CGSizeMake(100, 100))
        var sizeOfImage:CGRect  = contactImage.frame
        sizeOfImage.size    = smallPicture.size
        contactImage.frame  = sizeOfImage
        picker.dismissViewControllerAnimated(true, completion: nil)
        contactImage.image = smallPicture

        imageDataVar = UIImagePNGRepresentation(smallPicture)!
    }

}

Answer 1

You are currently converting the NSData to a String using the data's description method. Never do that.

A much better solution would be to simply put the data in the dictionary as-is since you are archiving the dictionary and sending the data. No need to convert the image data into a string.

Then on the receiving end, you unarchive the received data and the dictionary already has the PNG data for the image.