S3Uploader.swift

import AWSS3

class S3Uploader: NSObject, NSURLSessionDelegate, NSURLSessionTaskDelegate, NSURLSessionDataDelegate {
    var urlSession: NSURLSession?
    var uploadTask: NSURLSessionUploadTask?
    var url: String?
    var filename: String?
    var callback: ((Bool, String?) -> Void)? = nil;
    
    //This needs to Deinit when unwind segue, but right now it only deinits sometimes !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    deinit {
        println("Deinit S3Uploader")
    }
    
    override init() {
        super.init()
        
        //Init Connection to S3
        struct Static {
            static var session: NSURLSession?
            static var token: dispatch_once_t = 0
        }
        
        //dispatch_once(&Static.token) { [unowned self] in
            let configuration = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier(CONSTANTS.BackgroundSessionUploadIdentifier)
            Static.session = NSURLSession(configuration: configuration, delegate: self, delegateQueue: nil)
        //}
        
        self.urlSession = Static.session
        
    }
    
    convenience init(url: NSURL, contentType: String) {
        self.init()
        self.uploadToS3(url, contentType: contentType)
    }
    
    convenience init(url: NSURL, contentType: String, onCompletion: ((success: Bool, url: String?) -> Void)?){
        self.init();
        callback = onCompletion;
        self.uploadToS3(url, contentType: contentType)
    }
    
    func generateKey(contentType: String) -> String {
        let timestamp = NSDate().timeIntervalSince1970
        var ret = timestamp.description + CONSTANTS.UID;
        //TODO: we could actually look at the file contents here to decide
        switch(contentType.lowercaseString){
        case "movie/mp4":
            ret += ".mp4"
        case "image/jpg", "image/jpeg":
            ret += ".jpg"
        case "image/png":
            ret += ".png"
        default:
            ret += ".txt"
        }
        return ret;
    }
    
    
    
    func uploadToS3(url:NSURL, contentType: String?) -> String? {
        if (self.uploadTask != nil){
            return nil;
        }
        
        self.filename = self.generateKey(contentType!);
        
        let getPreSignedURLRequest = AWSS3GetPreSignedURLRequest()
        getPreSignedURLRequest.bucket = CONSTANTS.S3BucketName
        getPreSignedURLRequest.key = filename
        getPreSignedURLRequest.HTTPMethod = AWSHTTPMethod.PUT
        getPreSignedURLRequest.expires = NSDate(timeIntervalSinceNow: 3600)
        
        
        getPreSignedURLRequest.contentType = contentType
        
        
        AWSS3PreSignedURLBuilder.defaultS3PreSignedURLBuilder().getPreSignedURL(getPreSignedURLRequest).continueWithBlock { [unowned self] (task:AWSTask!) -> (AnyObject!) in
            
            if (task.error != nil) {
                NSLog("Error: %@", task.error)
            } else {
                
                let presignedURL = task.result as! NSURL!
                if (presignedURL != nil) {
                    //NSLog("upload presignedURL is: \n%@", presignedURL)
                    
                    var request = NSMutableURLRequest(URL: presignedURL)
                    request.cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData
                    request.HTTPMethod = "PUT"
                    
                    //contentType in the URLRequest must be the same as the one in getPresignedURLRequest
                    request .setValue(contentType, forHTTPHeaderField: "Content-Type")
                    
                    self.uploadTask = self.urlSession?.uploadTaskWithRequest(request, fromFile: url)
                    self.uploadTask?.resume()
                    
                }
            }
            return nil;
        }
        
        self.url = "https://s3-us-west-1.amazonaws.com/fireworksprofiles/" + self.filename!;
        println("setting new url to: "+self.url!)
        return self.url;
        
    }
    
    //TODO: retry on fail
    
    func URLSession(session: NSURLSession, task: NSURLSessionTask, didSendBodyData bytesSent: Int64, totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
        
        let progress = Float(totalBytesSent) / Float(totalBytesExpectedToSend)
        
        
        let notification = NSNotification(name: NotificationCenters.UploadPercentage,
            object: ["type": "progress", "progress": progress.description])
        NSNotificationCenter.defaultCenter().postNotification(notification)
        
        //NSLog("UploadTask progress: %lf", progress)
        
        /*
        dispatch_async(dispatch_get_main_queue()) {
        self.progressView.progress = progress
        self.statusLabel.text = "Uploading..."
        }*/
        
    }
    
    func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?) {
        
        if (error == nil) {
            /*dispatch_async(dispatch_get_main_queue()) {
            self.statusLabel.text = "Upload Successfully"
            }*/
            NSLog("S3 UploadTask Completed Successfully");
            let notification = NSNotification(name: NotificationCenters.UploadPercentage,
                object: ["type": "finished", "progress": "100", "success": "true", "url": self.url!])
            NSNotificationCenter.defaultCenter().postNotification(notification)
            
            
        } else {
            /*dispatch_async(dispatch_get_main_queue()) {
            self.statusLabel.text = "Upload Failed"
            }*/
            let notification = NSNotification(name: NotificationCenters.UploadPercentage,
                object: ["type": "error", "progress": "100"])
            NSNotificationCenter.defaultCenter().postNotification(notification)
            
            
            NSLog("S3 UploadTask: %@ completed with error: %@", task, error!.localizedDescription);
            
        }
        if(callback != nil){
            callback!(error == nil, self.url);
        }
        
        self.urlSession?.finishTasksAndInvalidate();
        self.urlSession = nil
        self.uploadTask = nil
    }
    
    func URLSessionDidFinishEventsForBackgroundURLSession(session: NSURLSession) {
        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        if ((appDelegate.backgroundUploadSessionCompletionHandler) != nil) {
            let completionHandler:() = appDelegate.backgroundUploadSessionCompletionHandler!;
            appDelegate.backgroundUploadSessionCompletionHandler = nil
            completionHandler
        }
        NSLog("Completion Handler has been invoked, background upload task has finished.");
    }
    
    
}