I deployed my code before Swift 2 came out and with Crashlytics I get about 2-3 crashes a day supposedly in this func. I can't, for the life of me, figure out what's going on. I have thousands of users but out of the myriad that use the app I end up getting about 8-10 a day where Crashlytics reports something wrong.
The error is:
_TFZFC11 GProxy8GetAsyncFMS0_U_S_14Deserializable__FTGCS_10
GRequestQ__8callbackFGCS_11 GResponseGSaQ0___
T__T_U_FTGSQCSo6NSData_GSQCSo13 NSURLResponse_GSQCSo7 NSError__T_
(GProxy.swift:141)
I am making a request to my server and processing an array back and doing something with it in my callback (further up the chain somewhere else in my app).
Here is the code:
class func GetAsync<R, T: Deserializable>(request: GRequest<R>, callback: (GResponse<Array<T>>) -> ())
{
var list = Array<T>()
var response = GResponse<Array<T>>()
let serverRequest = NSMutableURLRequest(URL: NSURL(string: API_URL + request.Url)!)
serverRequest.HTTPMethod = "GET"
let task = NSURLSession.sharedSession().dataTaskWithRequest(serverRequest,
completionHandler: {
data, r, error in
if error != nil {
response.Status = .ERROR
} else {
do
{
let responseArray = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) as! NSArray
for item: AnyObject in responseArray {
let row = T(dict: item as! NSDictionary)
list.append(row)
}
response = GResponse<Array<T>>(status: ResponseCode.OK, value: list)
}
catch let err as NSError{
//I now log here (this is new code, before I was not)
}
}
callback(response)
})
task.resume()
}
Are there any major faux pas here where a crash may occur? See any glaring errors or potential concerns? I don't have the actual source anymore of when I deployed (I made changes to this class so I don't recall what line 141 is, but the crash message seems to do with NSURLResponse and the like. Any thoughts?
Thanks so much!
Related
Thanks in advance for any help. I am trying to get Batch items (Load multiple) items from one DynamoDb table using the AWS iOS SDK (Swift). I can load one item using the Block syntax, but I need to load 10 or more than that. I don't want to use 10 Block calls to load them individually. I tried to follow the attach stackoverflow Link (where the similar solution is given) but I am getting the following compiler error message. I come from Java background, hence could also be a syntax issue. Is it the right way to load multiple items? I don't want to use low level API. Any help, where I am going wrong. Thanks.
aws dynamodb how to use object mapper with batch get in ios
let dynamoDBObjectMapper = AWSDynamoDBObjectMapper.default()
var tasksList = Array<AWSTask<AnyObject>>()
for i in 1...10 {
tasksList.append(dynamoDBObjectMapper.load(AWSCards.self, hashKey: "SH_"+String(i), rangeKey: nil))
}
AWSTask.init(forCompletionOfAllTasksWithResults: tasksList).continueWithBlock { (task) -> AnyObject? in
if let cards = task.result as? [AWSCards] {
print(cards.count)
}
else if let error = task.error {
print(error.localizedDescription)
}
return nil
}
Have a try with the following codes (Swift 4.1, Feb 9th, 2018):
let dynamoDBObjectMapper = AWSDynamoDBObjectMapper.default()
var tasksList = Array<AWSTask<AnyObject>>()
for i in 1...10 {
tasksList.append(dynamoDBObjectMapper.load(AWSCards.self, hashKey: "SH_"+String(i), rangeKey: nil))
}
AWSTask<AnyObject>.init(forCompletionOfAllTasksWithResults: tasksList).continueWith { (task) -> Any? in
if let cards = task.result as? [AWSCards] {
print(cards.count)
}
else if let error = task.error {
print(error.localizedDescription)
}
return nil
}
Your question is "how to use the object mapper" but it might be more efficient for you to not use it.
However, there is a way to use it. See Niklas's answer here and here (he copy & pasted), but something about it strikes me as fishy. I want to make the assertion that it is not as fast as the built-in batch-get function, but I am unsure. I suspect that this does not complete the items in parallel, or at least not as efficiently as in BatchGetItem.
See the docs: "In order to minimize response latency, BatchGetItem retrieves items in parallel."
According to Yosuke, "Currently, AWSDynamoDBObjectMapper does not support the batch get item. You need to load one item at a time if you want to use the object mapper" as of 2016. This still seems to be the case. I am using a version a couple versions behind, but not too far behind. Someone check.
In conclusion, if you are loading one item at a time, you are likely missing out on the whole purpose of BatchGetItem (low latency).
Pulling from various sources, including John Davis's question here, I have tested and ran this BatchGetItem result. Here ya go.
import AWSDynamoDB
let primaryKeyToSortKeyDict : [String : String] = .... // Your stuff
var keys = [Any]()
for key in primaryKeyToSortKeyDict.keys {
let partitionKeyValue = AWSDynamoDBAttributeValue()
partitionKeyValue?.s = String(key)
let sortValue = AWSDynamoDBAttributeValue()
sortValue?.s = String(primaryKeyToSortKeyDict[key]!)
keys.append(["partitionKeyAttributeName": partitionKeyValue, "sortKeyAttributeName": sortValue])
}
let keysAndAttributesMap = AWSDynamoDBKeysAndAttributes()
keysAndAttributesMap?.keys = keys as? [[String : AWSDynamoDBAttributeValue]]
keysAndAttributesMap?.consistentRead = true
let tableMap = [table : keysAndAttributesMap]
let request = AWSDynamoDBBatchGetItemInput()
request?.requestItems = tableMap as? [String : AWSDynamoDBKeysAndAttributes]
request?.returnConsumedCapacity = AWSDynamoDBReturnConsumedCapacity.total
guard request != nil else {
print("Handle some error")
return
}
AWSDynamoDB.default().batchGetItem(request!) { (output, error) in
print("Here is the batchgetitem output")
if error == nil {
// do output stuff
} else {
// handle error
}
}
I used to build my app on Firebase before and there was a method which listens for value updates, something like this:
refHandle = postRef.observeEventType(FIRDataEventType.Value, withBlock: { (snapshot) in
let postDict = snapshot.value as! [String : AnyObject]
// ...
})
Now I'm not using firebase anymore, I'm using deployd and I use Alamofire to retrieve data in JSON. I wonder if there is an event listener in Alamofire that can execute code if the value is changing in the database, instead of retrieving the value every 2 minutes.
Thanks.
Okay so I found this thing called TRVSEventSource which is meant for handling SSE events.
So I added the following code after adding the header files and bridging them like this:
let configs = NSURLSessionConfiguration.defaultSessionConfiguration()
configs.HTTPAdditionalHeaders = ["Accept" : "text/event-stream"]
let eventsource = TRVSEventSource(URL: NSURL(string: "https://app.firebaseio.com/about.json?auth=<Your Database Secret>"), sessionConfiguration: configs)
eventsource.delegate = self
eventsource.open()
After that using the TRVSEventSourceDelegate, I added this delegate to get the information:
func eventSource(eventSource: TRVSEventSource!, didReceiveEvent event: TRVSServerSentEvent!) {
do{
let data = try NSJSONSerialization.JSONObjectWithData(event.data, options: .MutableContainers)
print(data)
}
catch let error
{
print(error)
}
}
The following prints something like this {
data = {
desc = "My Data";
};
path = "/";
}
And with that also tells you within what path of the JSOn file has been edited or added, idk how to handle things separately and stuff but I think you can handle the rest XD. Not a good answer but I hope I helped XD (First time properly answering something)
I have the HTTP code in an AngularJS controller:
$http.post('/api/users/authenticate', {email: $scope.email, password: $scope.password})
.success(function (data, status, headers, config) {
authService.login($scope.email);
$state.go('home');
})
.error(function (data, status, headers, config) {
$scope.errorMessages = data;
$scope.password = "";
});
In the success case, the server will respond with a JSON representation of a user. In the error case the server will respond with a simple string such as User not found which can be accessed through the data parameter.
I'm having trouble figuring out how to do something similar in Alamofire. Here's what I have right now:
#IBAction func LoginPressed(sender: AnyObject) {
let params: Dictionary<String,AnyObject> = ["email": emailField.text, "password": passwordField.text]
Alamofire.request(.POST, "http://localhost:3000/api/users/authenticate", parameters: params)
.responseJSON {(request, response, data, error) in
if error == nil {
dispatch_async(dispatch_get_main_queue(), {
let welcome = self.storyboard?.instantiateViewControllerWithIdentifier("login") as UINavigationController;
self.presentViewController(welcome, animated: true, completion: nil);
})
}
else{
dispatch_async(dispatch_get_main_queue(), {
// I want to set the error label to the simple message which I know the server will return
self.errorLabel.text = "something went wrong"
});
}
}
}
I have no idea if I'm handling the non-error case correctly either and would appreciate input on that as well.
You are are on the right track, but you are going to run into some crucial issues with your current implementation. There are some low level Alamofire things that are going to trip you up that I want to help you out with. Here's an alternative version of your code sample that will be much more effective.
#IBAction func loginPressed(sender: AnyObject) {
let params: [String: AnyObject] = ["email": emailField.text, "password": passwordField.text]
let request = Alamofire.request(.POST, "http://localhost:3000/api/users/authenticate", parameters: params)
request.validate()
request.response { [weak self] request, response, data, error in
if let strongSelf = self {
let data = data as? NSData
if data == nil {
println("Why didn't I get any data back?")
strongSelf.errorLabel.text = "something went wrong"
return
} else if let error = error {
let resultText = NSString(data: data!, encoding: NSUTF8StringEncoding)
println(resultText)
strongSelf.errorLabel.text = "something went wrong"
return
}
var serializationError: NSError?
if let json: AnyObject = NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments, error: &serializationError) {
println("JSON: \(json)")
let welcome = self.storyboard?.instantiateViewControllerWithIdentifier("login") as UINavigationController
self.presentViewController(welcome, animated: true, completion: nil)
} else {
println("Failed to serialize json: \(serializationError)")
}
}
}
}
Validation
First off, the validate function on the request will validate the following:
HTTPStatusCode - Has to be 200...299
Content-Type - This header in the response must match the Accept header in the original request
You can find more information about the validation in Alamofire in the README.
Weakify / Strongify
Make sure to weak self and strong self your closure to make sure you don't end up creating a retain cycle.
Dispatch to Main Queue
Your dispatch calls back to the main queue are not necessary. Alamofire guarantees that your completion handler in the response and responseJSON serializers is called on the main queue already. You can actually provide your own dispatch queue to run the serializers on if you wish, but neither your solution or mine are currently doing so making the dispatch calls to the main queue completely unnecessary.
Response Serializer
In your particular case, you don't actually want to use the responseJSON serializer. If you do, you won't end up getting any data back if you don't pass validation. The reason is that the response from the JSON serialization is what will be returned as the AnyObject. If serialization fails, the AnyObject will be nil and you won't be able to read out the data.
Instead, use the response serializer and try to parse the data manually with NSJSONSerialization. If that fails, then you can rely on the good ole NSString(data:encoding:) method to print out the data.
Hopefully this helps shed some light on some fairly complicated ways to get tripped up.
So Alamofire treats all requests successful. This really comes down to the API server http headers being returned.
You could use Alamofire.Request.validate()
It'll allow you to validate http headers, etc. Check out the example
https://github.com/Alamofire/Alamofire#validation
I am assuming the the error message will be in the data object.
to access the values from data you could do something like
I am not really sure about your api response looks but in this example
{
"message": "Could not authenticate"
}
let message: String? = data?.valueForKey("message") as String
in my app I'm using JSON and I made a session recently so if I would like to make some http request to get data for a specific user, the user must log in before (also used by http request).
in the safari when I entering the url's of login and then the url of receive data, it does that as needed.
but in my app, I first call login and then the url for getting data, but it's probably starting a new session in every url request which leads me to get an error and not receive the data.
my url request function is:
static func urlRequest (adress: String, sessionEnded: (NSDictionary->Void)?){
println(adress)
var urli = NSURL(string: adress)
var request = NSURLRequest(URL: urli!)
var rVal = "";
self.task = NSURLSession.sharedSession().dataTaskWithURL(urli!) {(data, response, error) in
var parseError: NSError?
let parsedObject: AnyObject? = NSJSONSerialization.JSONObjectWithData(data,
options: NSJSONReadingOptions.AllowFragments,
error:&parseError)
let po = parsedObject as NSDictionary
if let a = sessionEnded{
sessionEnded!(po)
}
}
task!.resume()
}
thanks in advance!!
You have shared only half of the puzzle with us, the client code. We can't comment on why the app isn't working with a clearer picture of what the server API. For example, once you "log in", how do subsequent queries confirm that the request is coming from valid session. Furthermore, you report that "every url request which leads me to get an error". Well, what error do you receive? You have to be far more specific regarding the precise errors/crashes you are receiving. BTW, are you logging on to some service with a well-defined API or are you writing that code yourself, too?
Having said that, I might suggest a few refinements to this method:
The sessionEnded (which I've renamed completionHandler to conform to informal standard naming conventions), probably should return an optional NSError object, too, so the caller can detect if there was an error.
Your unwrapping of the sessionEnded completion handler can be simplified to use ?.
When you parse the object, you should feel free to perform the optional cast, too.
You probably want to detect a network error (in which case data would be nil) and return the network NSError object.
Minor point, but I'd probably also rename the function to conform to Cocoa naming conventions, using a verb to start the name. Perhaps something like performURLRequest.
This is your call, but I'd be inclined to have the method return the NSURLSessionTask, so that the caller could use that task object if it wanted to (e.g. save the task object so that it could cancel it later if it wanted to).
Thus, that yields something like:
func performURLRequest (address: String, completionHandler: ((NSDictionary!, NSError!) -> Void)?) -> NSURLSessionTask {
let url = NSURL(string: address)
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data, response, error) in
if data == nil {
sessionEnded?(nil, error)
} else {
var parseError: NSError?
let parsedObject = NSJSONSerialization.JSONObjectWithData(data, options: nil, error:&parseError) as? NSDictionary
completionHandler?(parsedObject, parseError)
}
}
task.resume()
return task
}
And you'd invoke it like:
performURLRequest("http://www.example.com/some/path") { responseDictionary, error in
if responseDictionary == nil {
// handle error, e.g.
println(error)
return
}
// use `responseDictionary` here
}
Hey stackoverflow members,
I work really hard on getting better on Swift, now I have a trivial problem. I'm a former C# developer so Error Handling until now was try {}... catch {}... Message... Done!
Now I'm developing an App which uses some JSON APIs. It's all working, downloading JSON Data, pack them into my Objects but there is one problem. The proper Error Handling..
I have the following code to download & parse JSON:
//Download & Parse JSON
func getJSON(urlToRequest: String) -> NSDictionary {
var url: NSURL = NSURL(string: urlToRequest)
var jsonRequest: NSURLRequest = NSURLRequest(URL: url)
var jsonResponse: AutoreleasingUnsafePointer<NSURLResponse?> = nil
var error: NSError?
var dataValue: NSData = NSURLConnection.sendSynchronousRequest(jsonRequest, returningResponse: jsonResponse, error:&error)
if error.description.isEmpty {
var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataValue, options: NSJSONReadingOptions.MutableContainers, error: &error) as NSDictionary
if error.description.isEmpty {
return jsonResult
}
else {
return NSDictionary(object: "Error: Something with parsing went wrong :(", forKey: "error")
}
}
else {
return NSDictionary(object: "Error: There was an error with your connection :(", forKey: "error")
}
}
The error part is just temporary, the problem is my ViewController just calls one function to get the whole data for the week (days, matchups and so on)
I call it this way:
var rWrapper = RiotWrapper()
let lcsWeek: Week = rWrapper.getWeek("2014-07-07")
My getWeek method calls 3-4 functions which all parse JSON data in relation to the previous responses.
Ok, long story short question: I want to abort all Tasks if JSON or HTTP fails and fill my TableView just with an error message, how can I achieve this?
Something like: if error occurred -> Stop whatever you are doing -> return for example a null erm.. nil for week -> print error
Can someone help me? If someone have some lecture according this topic it will be fine also :D
Thanks in advance!
Btw: sorry for my "bad" english
All of your JSON parsing methods including getWeek should return a tuple with an optional return value and an error. If at any point you get an error in one of your methods from the JSON parsing, just immediately return the error with nil for the return value. Each method up the chain should check for an error from the previous methods and immediately return the error if it finds one:
func getWeek(string : String) -> (Week?, NSError) {
let (result, error) = self.otherMethod()
if error {
return (nil, error)
}
// continue happily ...
}
I would suggest having your function return an optional. It is easy to test and functions can be chained and shortcut.
func getWeek(string : String) -> Week? {
...
if error {
return nil
}
}
This can be quickly evaluated like this:
if let week = getWeek("2014-07-07") {
// handle success case
} else {
// handle nil
}
and check here for how to string together a number of functions that return optional:
https://developer.apple.com/library/prerelease/mac/documentation/Swift/Conceptual/Swift_Programming_Language/OptionalChaining.html