Checking metadata of Amazon S3 file using iOS AWS SDK in Swift

Question

I am using the AWS iOS SDK v2, and Swift 1.2.

I am storing my app\'s app.json file on S3 and want to check it at launch to see if it\'s been updated sin

Answer 1

You need to call headobject method of AWSS3

     var request = AWSS3HeadObjectRequest()

    request.bucket = "flkasdhflhad"
    request.key = "hfsdahfjkhadjkshf"

   request.ifModifiedSince = NSDate()


  var s3 = AWSS3.defaultS3()

    s3.headObject(request) { ( output1 : AWSS3HeadObjectOutput?, error : NSError?) -> Void in
   print( output1?.description())
    }

if your object is modified from specified date then it will return u the object otherwise it will return u the status code 304.

Answer 2

You need to use AWSS3 (instead of AWSS3TransferManager) to call - headObject:.

Answer 3

You can use following Swift 2.2 method to check if file exist or not

func checkIfFileExist() {
    let s3 = AWSS3.defaultS3()
    let headObjectsRequest = AWSS3HeadObjectRequest()
    headObjectsRequest.bucket = "YourBucketName" //Don't add "/" at end of your bucket Name    

    headObjectsRequest.key = "YourFileNameYouWantToCheckFor" //Don't add "/" in start of file name 

    s3.headObject(headObjectsRequest).continueWithBlock { (task) -> AnyObject! in
        if let error = task.error {
            print("Error to find file: \(error)")

        } else {
            print("fileExist")
        }
    }

}

Note: Example to set bucket and key

suppose you have bucket named "ABC" and than folder named "XYZ" and than inside "XYZ" you have file "abc123"

than write

headObjectsRequest.bucket = "ABC/XYZ"

and

headObjectsRequest.key = "abc123"

and if you want to check for the entire folder

than use

headObjectsRequest.bucket = "ABC/XYZ"

and

headObjectsRequest.key = ""

Thanks Mohsin