Parsing JSON data with Gloss and Alamofire in swift - json

Question

I trying to decode an json object from a webrequest with Swift 3, Gloss 1.1 and Alamofire 4.0:
The json response looks like this:
{
"code": "0",
"message": "OK.",
"data": [
{
"timestamp": 1480885860,
"open": 10.99
},
{
"timestamp": 1480886040,
"open": 11
}
]
}
My json Decodables are the following two:
struct ResponseJsonModel : Decodable {
let code : Int
let message : String
let data : [MarketPriceJsonModel]?
// <~~
init?(json: JSON) {
guard let codeInt : Int = "code" <~~ json else {
print("code unwrapping failed in guard")
return nil
}
guard let messageStr : String = "message" <~~ json else {
print("message unwrapping failed in guard")
return nil
}
self.code = codeInt
self.message = messageStr
self.data = "data" <~~ json
}
}
struct MarketPriceJsonModel : Decodable {
let timestamp : NSDate
let open : Double
init?(json: JSON) {
guard let timestampInt : Int = "timestamp" <~~ json else {
print("timestamp unwrapping failed in guard")
return nil
}
guard let open : Double = "open" <~~ json else {
print("open price unwrapping failed in guard")
return nil
}
self.timestamp = NSDate(timeIntervalSince1970: Double(timestampInt))
self.open = open
}
}
I'm new to Gloss and don't understand why the initalize of my decodable-Object fails.
Alamofire.request(url).validate().responseJSON { response in
switch response.result {
case .success:
guard let value = response.result.value as? JSON,
let responseModel = ResponseJsonModel(json: value) else {
print("responseModel failed")
return
}
print(responseModel.message)
case .failure(let error):
print(error)
}
}
The output of the code is
code unwrapping failed in guard
responseModel failed
but why?
When I add a breakpoint in init?() and look at the json-variable in the debug area, so the request looks ok but the parsing fails.
Is there a way to get better exception messages in case something fails?
Any input appreciated.

Answer 1

Ok, problem solved. It was a faulty configuration of the webservice.
As you can see, the json response of the code attribute was:
"code": "0",
This format clearly stands for a string, therefor my guard with parsing into Int will fail.
To solve this, there are two possible ways I found.
Option 1: either change json response to:
"code": 0,
(value has no more surrounding quotes). This is probably the best solution as it fixes the wrong datatype of the webservice, but it requires to have full control over the codebase of the service.
Option 2: simply parse the json response into a String and after that, force-unwrap into an Int workes too. For this solution the webservice will remain unchanged.
guard let codeStr : String = "code" <~~ json else {
print("code unwrapping failed in guard")
return nil
}
self.code = Int(codeStr)!