Upload Image to AWS S3 Bucket. In Swift.

In this blog post I am going to share with you how to upload an image to Amazon AWS S3 Bucket. I have split information into smaller videos and it will cover:

  • Create AWS S3 Bucket
  • Edit S3 Bucket policy to allow users read files from it
  • Use AWS Cognito to create a Federated Identity Pool
  • Install CocoaPods and use it to download AWS SDK for iOS
  • Write Swift code to upload image to AWS S3 Bucket

Introduction

Create AWS S3 Bucket

AWS Bucket Policy 

{
 "Version": "2008-10-17",
 "Statement": [
  {
   "Sid": "AddPerm",
   "Effect": "Allow",
   "Principal": "*",
   "Action": "s3:GetObject",
   "Resource": "arn:aws:s3:::learn-swift/*"
  }
 ]
}

 

Create Federated Identity Pool with AWS Cognito

Download and Setup AWS SDK for iOS Platform

Write Code to Upload Image to AWS S3 Bucket

Select image with UIImagePickerController and upload it to AWS S3 bucket

Upload Image to AWS S3 Bucket. Source code in Swift

import UIKit
import AWSCore
import AWSS3
import Photos

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
  
    var showImagePickerButton: UIButton!
    var myImageView: UIImageView!
    var selectedImageUrl: NSURL!
    var myActivityIndicator: UIActivityIndicatorView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
         setupImagePickerButton()
        
         setupImageView()
        
         setupUploadButton()
        
         setUpActivityIndicator()
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

    }
    
    func startUploadingImage()
    {
        var localFileName:String?

        if let imageToUploadUrl = selectedImageUrl
        {
            let phResult = PHAsset.fetchAssetsWithALAssetURLs([imageToUploadUrl], options: nil)
            localFileName = phResult.firstObject?.filename
        }
        
        if localFileName == nil
        {
            return
        }
        
        myActivityIndicator.startAnimating()
  
        // Configure AWS Cognito Credentials
        let myIdentityPoolId = ""
        
        let credentialsProvider:AWSCognitoCredentialsProvider = AWSCognitoCredentialsProvider(regionType:AWSRegionType.-- USEast1, identityPoolId: myIdentityPoolId)
        
        let configuration = AWSServiceConfiguration(region:AWSRegionType.-- USEast1, credentialsProvider:credentialsProvider)
        
        AWSServiceManager.defaultServiceManager().defaultServiceConfiguration = configuration
        
        // Set up AWS Transfer Manager Request
        let S3BucketName = "learn-swift"
  
        let remoteName = localFileName!
        
        let uploadRequest = AWSS3TransferManagerUploadRequest()
        uploadRequest.body = generateImageUrl(remoteName)
        uploadRequest.key = remoteName
        uploadRequest.bucket = S3BucketName
        uploadRequest.contentType = "image/jpeg"
 
        
        let transferManager = AWSS3TransferManager.defaultS3TransferManager()
        
        // Perform file upload
        transferManager.upload(uploadRequest).continueWithBlock { (task) -> AnyObject! in
            
            dispatch_async(dispatch_get_main_queue()) {
              self.myActivityIndicator.stopAnimating()
            }
            
            if let error = task.error {
                print("Upload failed with error: (\(error.localizedDescription))")
            }
            
            if let exception = task.exception {
                print("Upload failed with exception (\(exception))")
            }
            
            if task.result != nil {
                
                let s3URL = NSURL(string: "https://s3.amazonaws.com/\(S3BucketName)/\(uploadRequest.key!)")!
                print("Uploaded to:\n\(s3URL)")

                // Remove locally stored file
                self.remoteImageWithUrl(uploadRequest.key!)
                
                 dispatch_async(dispatch_get_main_queue()) {
                    self.displayAlertMessage()
                }
                
                
            }
            else {
                print("Unexpected empty result.")
            }
            return nil
        }

    }
    
    func displayAlertMessage()
    {
        let alertController = UIAlertController(title: "Alert title", message: "Image has been uploaded", preferredStyle: .Alert)
        
        let OKAction = UIAlertAction(title: "OK", style: .Default) { (action:UIAlertAction!) in
            
            // Code in this block will trigger when OK button tapped.
            print("Ok button tapped");
            
        }
        
        alertController.addAction(OKAction)
        
        self.presentViewController(alertController, animated: true, completion:nil)
    }
    
    
    func generateImageUrl(fileName: String) -> NSURL
    {
        let fileURL = NSURL(fileURLWithPath: NSTemporaryDirectory().stringByAppendingString(fileName))
        let data = UIImageJPEGRepresentation(myImageView.image!, 0.6)
        data!.writeToURL(fileURL, atomically: true)
       
        return fileURL
    }
    
    func remoteImageWithUrl(fileName: String)
    {
        let fileURL = NSURL(fileURLWithPath: NSTemporaryDirectory().stringByAppendingString(fileName))
        do {
            try NSFileManager.defaultManager().removeItemAtURL(fileURL)
        } catch
        {
            print(error)
        }
    }
    
    func setupImagePickerButton()
    {
        let button = UIButton(type: UIButtonType.System) as UIButton
        
        let xPostion:CGFloat = 50
        let yPostion:CGFloat = 100
        let buttonWidth:CGFloat = 150
        let buttonHeight:CGFloat = 45
        
        button.frame = CGRectMake(xPostion, yPostion, buttonWidth, buttonHeight)
        
        button.backgroundColor = UIColor.lightGrayColor()
        button.setTitle("Select image", forState: UIControlState.Normal)
        button.tintColor = UIColor.blackColor()
        button.addTarget(self, action: #selector(ViewController.displayImagePickerButtonTapped) , forControlEvents: .TouchUpInside)
        self.view.addSubview(button)
    }
    
    func setupImageView()
    {
        myImageView = UIImageView()
        
        let xPostion:CGFloat = 50
        let yPostion:CGFloat = 200
        let buttonWidth:CGFloat = 200
        let buttonHeight:CGFloat = 200
        
        myImageView.frame = CGRectMake(xPostion, yPostion, buttonWidth, buttonHeight)
        
        self.view.addSubview(myImageView)
    }
    
    func setupUploadButton()
    {
        let rightBarButton = UIBarButtonItem(title: "Upload", style: UIBarButtonItemStyle.Plain, target: self, action: #selector(ViewController.startUploadingImage))
        self.navigationItem.rightBarButtonItem = rightBarButton
    }
    
    func setUpActivityIndicator()
    {
        //Create Activity Indicator
        myActivityIndicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
        
        // Position Activity Indicator in the center of the main view
        myActivityIndicator.center = view.center
        
        // If needed, you can prevent Acivity Indicator from hiding when stopAnimating() is called
        myActivityIndicator.hidesWhenStopped = true
        
        myActivityIndicator.backgroundColor = UIColor.whiteColor()
 
        view.addSubview(myActivityIndicator)
    }
    
    func displayImagePickerButtonTapped() {
        
        let myPickerController = UIImagePickerController()
        myPickerController.delegate = self;
        myPickerController.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
        
        self.presentViewController(myPickerController, animated: true, completion: nil)
        
    }
    
    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject])
    {
        selectedImageUrl = info[UIImagePickerControllerReferenceURL] as! NSURL

        myImageView.image = info[UIImagePickerControllerOriginalImage] as? UIImage
        myImageView.backgroundColor = UIColor.clearColor()
        myImageView.contentMode = UIViewContentMode.ScaleAspectFit
        self.dismissViewControllerAnimated(true, completion: nil)
    }
}

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Happy coding! 🙂