Swift do catch inside function doesn't work - ios

Question

I have a function which parses JSON, but I get a nil error dealing with the URL strings:
var jsonResponse: NSMutableDictionary?
do{
jsonResponse = try NSJSONSerialization.JSONObjectWithData(data!,
options: NSJSONReadingOptions.AllowFragments) as? NSMutableDictionary;
let info : NSArray = jsonResponse!.valueForKey("latest_receipt_info") as! NSArray
let transaction_id: String? = info[0].valueForKey("transaction_id") as? String
let purchase_date: String? = info[0].valueForKey("purchase_date") as? String
let product_id: String? = info[0].valueForKey("product_id") as? String
let web_order_line_item_id: String? = info[0].valueForKey("web_order_line_item_id") as? String
print("test")
// Send Values
let addIAPUrl:NSString = "http://bla.com/application/addIAP.php?transaction_id=\(transaction_id!)&purchase_date=\(purchase_date)&product_id=\(product_id)&web_order_line_item_id=\(web_order_line_item_id)&userID=\(prefs.valueForKey("userID") as! String!)"
self.apiRequests(addIAPUrl as String, completionHandler: { (success, message) -> Void in
print("success \(addIAPUrl)")
if(success == 1){
dispatch_async(dispatch_get_main_queue()){
// ADDED
print("success \(addIAPUrl)")
}
}else{
// DONT ADDED
}
})
The output doesn't return any error but the function fails after print("test"). The apiRequests function works in other cases, but doesn't seem to work in this context.
I would appreciate any help finding the problem.
Here is the code for the apiRequest function:
func apiRequests(url : String, completionHandler : ((success : Int, message : String) -> Void)) {
guard let url = NSURL(string: url as String) else {
return
}
let urlRequest = NSURLRequest(URL: url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)
let task = session.dataTaskWithRequest(urlRequest, completionHandler: { (data, response, error) in
guard let responseData = data else {
return
}
guard error == nil else {
print(error)
return
}
let post: NSDictionary
do {
post = try NSJSONSerialization.JSONObjectWithData(responseData,
options: []) as! NSDictionary
} catch {
return
}
let numberFromString = Int((post["success"] as? String)!)
completionHandler(success: (numberFromString)!, message: (post["message"] as? String)!)
})
task.resume()
}

Answer 1

It seems to me that the problem is most likely that your apiRequests: function is erroring at one of many places, and is returning instead of calling your callback with an error state.
func apiRequests(url : String, completionHandler : ((success : Int, message : String) -> Void)) {
guard let url = NSURL(string: url as String) else {
completionHandler(0, "Couldn't get URL")
return
}
let urlRequest = NSURLRequest(URL: url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)
let task = session.dataTaskWithRequest(urlRequest, completionHandler: { (data, response, error) in
guard let responseData = data else {
completionHandler(0, "Data was nil")
return
}
guard error == nil else {
print(error)
completionHandler(0, "Error wasn't nil")
return
}
let post: NSDictionary
do {
post = try NSJSONSerialization.JSONObjectWithData(responseData,
options: []) as! NSDictionary
} catch {
completionHandler(0, "Error with NSJSONSerialization")
return
}
let numberFromString = Int((post["success"] as? String)!)
completionHandler(success: (numberFromString)!, message: (post["message"] as? String)!)
})
task.resume()
}
Side note, but not related to the fix,
let addIAPUrl:NSString = "http://bla.com/application/addIAP.php?transaction_id=\(transaction_id!)&purchase_date=\(purchase_date)&product_id=\(product_id)&web_order_line_item_id=\(web_order_line_item_id)&userID=\(prefs.valueForKey("userID") as! String!)"
self.apiRequests(addIAPUrl as String, completionHandler: { (success, message) -> Void in
Can easily be replaced with
let addIAPUrl = "http://bla.com/application/addIAP.php?transaction_id=\(transaction_id!)&purchase_date=\(purchase_date)&product_id=\(product_id)&web_order_line_item_id=\(web_order_line_item_id)&userID=\(prefs.valueForKey("userID") as! String!)"
self.apiRequests(addIAPUrl, completionHandler: { (success, message) -> Void in
Because you are converting a String to an NSString then back to a String