Hi there and welcome. Today we will be talking about AWS S3 Image upload using AWS SDK for iOS v2 (WOW thats a lot of acronyms!). Last week I had to do this in a project and it took me and I was disappointed with the documentation, and sample project they had available. So in this tutorial I’m going to be showing a real world example where you would select an image from the gallery or take a photo on a device and upload that image to your bucket. If you want to follow along I have the projects available on github for both objective-c and swift! I also have a video of setting up S3 and Amazon Cognito at the end of the tutorial, but I have to apologize for the quality. I am terrible at making videos, and I was very tired when I made it (also my voice is very annoying).

Github Links

• S3 Objective-C Project
• S3 Swift Project

Also don’t forget to follow me on twitter if you ever want to chat about iOS or mobile development! Follow @BarrettBreshear.

Set up credentials

First thing we need to do is set up amazons credentials your app delegate’s didFinishLaunchingWithOptions method. In this demo we are going to use Cognito to manage access to our S3 bucket. If you want a full in depth look at how to do this watch the video at the end of the tutorial.

Objective-C

AppDelegate.m

//
//  AppDelegate.m
//  s3-objectiveC
//
//  Created by Barrett Breshears on 12/5/14.
//  Copyright (c) 2014 Barrett Breshears. All rights reserved.
//

#import "AppDelegate.h"
#import "AWSCore.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    AWSCognitoCredentialsProvider *credentialsProvider = [AWSCognitoCredentialsProvider
                                                          credentialsWithRegionType:AWSRegionUSEast1
                                                          accountId:@"#######"
                                                          identityPoolId:@"######"
                                                          unauthRoleArn:@"#####"
                                                          authRoleArn:@"######"];
    
    AWSServiceConfiguration *configuration = [AWSServiceConfiguration configurationWithRegion:AWSRegionUSEast1
                                                                          credentialsProvider:credentialsProvider];
    
    [AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application {
}

- (void)applicationDidEnterBackground:(UIApplication *)application {
}

- (void)applicationWillEnterForeground:(UIApplication *)application {
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
}

- (void)applicationWillTerminate:(UIApplication *)application {
}

@end

Swift

AppDelegate.swift

//
//  AppDelegate.swift
//  s3-swift
//
//  Created by Barrett Breshears on 12/6/14.
//  Copyright (c) 2014 Barrett Breshears. All rights reserved.
//

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.
        var credentialsProvider:AWSCognitoCredentialsProvider = AWSCognitoCredentialsProvider.credentialsWithRegionType(AWSRegionType.USEast1, accountId:"##########", identityPoolId:"#######", unauthRoleArn:"#######", authRoleArn:"########")
        
        var configuration:AWSServiceConfiguration = AWSServiceConfiguration(region: AWSRegionType.USEast1, credentialsProvider: credentialsProvider)
        
        AWSServiceManager.defaultServiceManager().setDefaultServiceConfiguration(configuration)
        
        
        
        return true
    }

    func applicationWillResignActive(application: UIApplication) {
    }

    func applicationDidEnterBackground(application: UIApplication) {
    }

    func applicationWillEnterForeground(application: UIApplication) {
    }

    func applicationDidBecomeActive(application: UIApplication) {
    }

    func applicationWillTerminate(application: UIApplication) {
    }


}

This is a pretty simple set up here, and if you configure your credentials in the Cognito console it will actually give you the code to set up your configuration.

Upload an image to S3

So the main difference between v1 and v2 is that you used to be able to set the upload body request to NSData or a NSURL. In v2 you can only set the upload request to a NSURL. So what we have to do is save the image to the app’s local directory and then we can create a local file url to send to amazon.

Objective-C

- (void)uploadToS3{
    // get the image from a UIImageView that is displaying the selected Image
    UIImage *img = _selectedImage.image;
    
    // create a local image that we can use to upload to s3
    NSString *path = [NSTemporaryDirectory() stringByAppendingPathComponent:@"image.png"];
    NSData *imageData = UIImagePNGRepresentation(img);
    [imageData writeToFile:path atomically:YES];
    
    // once the image is saved we can use the path to create a local fileurl
    NSURL *url = [[NSURL alloc] initFileURLWithPath:path];
    
    // next we set up the S3 upload request manager
    _uploadRequest = [AWSS3TransferManagerUploadRequest new];
    // set the bucket
    _uploadRequest.bucket = @"s3-demo-objectivec";
    // I want this image to be public to anyone to view it so I'm setting it to Public Read
    _uploadRequest.ACL = AWSS3ObjectCannedACLPublicRead;
    // set the image's name that will be used on the s3 server. I am also creating a folder to place the image in
    _uploadRequest.key = @"foldername/image.png";
    // set the content type
    _uploadRequest.contentType = @"image/png";
    // we will track progress through an AWSNetworkingUploadProgressBlock
    _uploadRequest.body = url;
    
    __weak ViewController *weakSelf = self;
    
    _uploadRequest.uploadProgress =^(int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend){
        dispatch_sync(dispatch_get_main_queue(), ^{
            weakSelf.amountUploaded = totalBytesSent;
            weakSelf.filesize = totalBytesExpectedToSend;
            [weakSelf update];
            
        });
    };
    
    // now the upload request is set up we can creat the transfermanger, the credentials are already set up in the app delegate
    AWSS3TransferManager *transferManager = [AWSS3TransferManager defaultS3TransferManager];
    // start the upload
    [[transferManager upload:_uploadRequest] continueWithExecutor:[BFExecutor mainThreadExecutor] withBlock:^id(BFTask *task) {
        
        // once the uploadmanager finishes check if there were any errors
        if (task.error) {
            NSLog(@"%@", task.error);
        }else{// if there aren't any then the image is uploaded!
            // this is the url of the image we just uploaded
            NSLog(@"https://s3.amazonaws.com/s3-demo-objectivec/foldername/image.png");
        }
        
        return nil;
    }];
    
}

Swift

 func uploadToS3(){
        
        // get the image from a UIImageView that is displaying the selected Image
        var img:UIImage = selectedImage!.image!
        
        // create a local image that we can use to upload to s3
        var path:NSString = NSTemporaryDirectory().stringByAppendingPathComponent("image.png")
        var imageData:NSData = UIImagePNGRepresentation(img)
        imageData.writeToFile(path, atomically: true)
        
        // once the image is saved we can use the path to create a local fileurl
        var url:NSURL = NSURL(fileURLWithPath: path)!
        
        // next we set up the S3 upload request manager
        uploadRequest = AWSS3TransferManagerUploadRequest()
        // set the bucket
        uploadRequest?.bucket = "s3-demo-swift"
        // I want this image to be public to anyone to view it so I'm setting it to Public Read
        uploadRequest?.ACL = AWSS3ObjectCannedACL.PublicRead
        // set the image's name that will be used on the s3 server. I am also creating a folder to place the image in
        uploadRequest?.key = "foldername/image.png"
        // set the content type
        uploadRequest?.contentType = "image/png"
        // and finally set the body to the local file path
        uploadRequest?.body = url;
        
        // we will track progress through an AWSNetworkingUploadProgressBlock
        uploadRequest?.uploadProgress = {[unowned self](bytesSent:Int64, totalBytesSent:Int64, totalBytesExpectedToSend:Int64) in
            
            dispatch_sync(dispatch_get_main_queue(), { () -> Void in
                self.amountUploaded = totalBytesSent
                self.filesize = totalBytesExpectedToSend;
                self.update()

            })
        }
        
        // now the upload request is set up we can creat the transfermanger, the credentials are already set up in the app delegate
        var transferManager:AWSS3TransferManager = AWSS3TransferManager.defaultS3TransferManager()
        // start the upload
        transferManager.upload(uploadRequest).continueWithExecutor(BFExecutor.mainThreadExecutor(), withBlock:{ [unowned self]
            task -> AnyObject in
            
            // once the uploadmanager finishes check if there were any errors
            if(task.error != nil){
                NSLog("%@", task.error);
            }else{ // if there aren't any then the image is uploaded!
                // this is the url of the image we just uploaded
                NSLog("https://s3.amazonaws.com/s3-demo-swift/foldername/image.png");
            }
            
            self.removeLoadingView()
            return "all done";
        })
        
    }

Once you understand how to configure your credentials and how to get the image from an image view to local file to url to amazon the process is pretty simple. Please let me know if you have any questions in the comments below or on send me a tweet Follow @BarrettBreshear
.

Setting up credentials and project walk through video