Issue with decoding base64 encoded app engine data in swift - swift

Question

I am developing ios app which is getting data from Google endpoint ,the data is base 64 encoded on the server to a custom java object, which is then returned by the endpoint method.
On the iOS side I am able to receive the data and print the data using the generated client code.
I am facing a problem and I am unable to decode the data back in to the GTL**** endpoint auto generated class.
The decoded data shows up with some hex numbers:
My Code:
let respo2 = GTLDecodeBase64(responce) as? GTLEndpointStatusCollection
I also tried decoding using the swift classes:
let respo = NSData(base64EncodedString: responce, options: NSDataBase64DecodingOptions(rawValue: 0))
The input is base64 encoded : rO0ABXNyABNqYXZhLnV0aWwuQXJyYXlMaXN0eIHSHZnHYZ......
The desired output should have been readable data,
but instead im getting:
<aced0005 73720013 6a617661 2e757469 6c2e4172 7261794c.....
I even tried encoding, decoding the base64 decoded data with NSUTF8
but no use.
What am I doing wrong? Is it possible for data encoded on Server in Java (with custom Java objects) to be decoded back ? (I understand Google endpoint does the serialization/deserialization in between)
Thanks in advance.

Answer 1

You should use JSON for serialization rather than manually converting the object to a bytestring and base64 encoding it. If you are using the Endpoints libraries this is automatically done for you, simply by returning the object in your method. See the docs here for an example and the rest of the Endpoints docs for more details. To consume the API you can use the generated iOS libraries which also do this for you as per the examples here. You won't actually see any JSON unless you inspect the HTTP traffic or use the API Explorer.
It sounds like you might just be doing more work than is needed by pre-encoding the object, rather than just letting Endpoints do it for you. If you really need to manually serialize an object to some property you can use a library on the Endpoints side like Jackson to serialize the object to a string property and NSJSONSerialization on the client to convert it back to an object.