AWSS3PresignedURLErrorDomain, iOS, AWSSDK v2 - ios

Question

Using AWSSDK V2 with iOS 8, went through sample code bases and setup
cognito with proper access to my S3Bucket. following example here
https://github.com/awslabs/aws-sdk-ios-samples/tree/master/S3BackgroundTransfer-Sample/Objective-C
When I try the upload I get this error
Error: Error Domain=com.amazonaws.AWSS3PresignedURLErrorDomain Code=1
"accessKey in credentialProvider can not be nil" UserInfo=0x7d905610
{NSLocalizedDescription=accessKey in credentialProvider can not be nil}
I made sure the role used by cognito poold id has access to my s3 bucket based on the policy I created for it. What could be the problem?
Agfter sebastians commnent, I went back and verified that I am using unauthenticated users, with a role that has access to my s3bucket, and then looked at the last comment he made about cognito being async and about its initialization. I am doing this in this method here
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
AWSCognitoCredentialsProvider *credentialsProvider = [AWSCognitoCredentialsProvider credentialsWithRegionType:CognitoRegionType
identityPoolId:CognitoIdentityPoolId];
AWSServiceConfiguration *configuration = [AWSServiceConfiguration configurationWithRegion:DefaultServiceRegionType
credentialsProvider:credentialsProvider];
[AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;
// Override point for customization after application launch.
return YES;
}
now when breaking on the line
[AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;
and inspecting in debugger the properties of credentialsProvider, It does have a lot of nil properties !!
credentialsProvider AWSCognitoCredentialsProvider * 0x7886a0d0 0x7886a0d0
NSObject NSObject
_useEnhancedFlow BOOL YES '\x01'
_identityId NSString * nil 0x00000000
_accessKey NSString * nil 0x00000000
_secretKey NSString * nil 0x00000000
_sessionKey NSString * nil 0x00000000
_expiration NSDate * nil 0x00000000
I did create the entity pool and embed the ID in my code, what should I look for here?

Answer 1

I had the exact same problem, however the answers above didn't help me either.
Changing
let CognitoRegionType = AWSRegionType.Unknown
let DefaultServiceRegionType = AWSRegionType.Unknown
To
let CognitoRegionType = AWSRegionType.EUWest1
let DefaultServiceRegionType = AWSRegionType.EUWest1
In Constants.swift solved it for me. Of course this is in the context of the sample application mentioned above.

Answer 2

From the error above, it looks like your CognitoCredentialsProvider has no access key / secret key.
When using Cognito with authenticated users, just creating an IdentityPool and creating an AWSCognitoCredentialsProvider instance is not enough.
You must write code to authenticate your user. Currently Cognito supports user authentication with Amazon, Facebook, Google, any generic OpenID Connect or your own backend.
Once you receive an authentication token from the Identity Provider, you can give it to Cognito (using its .logins property), Cognito will then exchange that token for a valid Access Key and Secret Key.
It looks like your Cognito Identity provider has no access key / secret key yet. The example you linked above is an example of Cognito usage for unauthenticated users - which might be valid for your application, or not. Depending on your use case.
Also remember that CognitoIdentitProvider class is asynchronous (like all AWS iOS SDK classes). Ensure that you are not calling your S3 Transfer Manager class before Cognito is fully initialized.
To better understand Cognito Identity, I would invite you to read http://docs.aws.amazon.com/mobile/sdkforios/developerguide/cognito-auth.html

Answer 3

after much inspection, I found the problem ( lack of documentation ).
I needed to create an online policy for the role used by cognito. when going to IAM services -> roles -> click on role -> permissions, under that tab there are two types of policies managed and inline, before I setup a managed policy which didn't do anything, so I went back and created an inline policy and that is where I give this role access to the S3 bucket, and now it works !!
Hope this helps someone else, and AWS really need to document better.