I have a working REST API based on this API Gateway tutorial. I'm able to successfully invoke it via the test functionality of the AWS Console; and I'm able to successfully invoke it via my simple iOS Swift 4.2 Xcode application using the iPhone XR simulator.
I know it's working via a real, live external call because I can see the Cloudwatch logs which always register a 200 response and is sending the results back to the Client.
My problem is really in understanding the Swift code, and I'm hoping that a Swift expert can help me understand how to unpack result in the code below.
Here's my code in ViewController.swift for invoking the REST API and attempting to print result to the console:
#IBAction func userInvokeApi(_ sender: UIButton) {
print("You clicked invoke api...")
let client = SVTLambdaGateClient.default()
client.calcGet(operand2: "3", _operator: "+", operand1: "5").continueWith{ (task: AWSTask?) -> AnyObject? in
if let error = task?.error {
print("Error occurred: \(error)")
return nil
}
if let result = task?.result {
// Do something with result
print("The result is... \(result)")
}
return nil
}
}
As pointed out in the comments below, I'm getting the following result because it's printing out the address of the object:
You clicked invoke api...
The result is... <AmplifyRestApiTest.Empty: 0x600002020770> {
}
(where AmplifyRestApiTest is the name of my Xcode project.)
UPDATE When I set a breakpoint on the print statement, this is what I see in the Debug pane:
UPDATE 2
When I type task?.result there are two viable properties as per this answer from the Amplify team: error and result. So, since my API responds successfully I am assuming I just don't know how to view result.
Can someone help me understand what steps I must take to access members of this class object?
Here is the corresponding method in the API Gateway-generated iOS Swift SDK code:
/*
#param operand2
#param _operator
#param operand1
return type: Empty
*/
public func calcGet(operand2: String, _operator: String, operand1: String) -> AWSTask<Empty> {
let headerParameters = [
"Content-Type": "application/json",
"Accept": "application/json",
]
var queryParameters:[String:Any] = [:]
queryParameters["operand2"] = operand2
queryParameters["operator"] = _operator
queryParameters["operand1"] = operand1
let pathParameters:[String:Any] = [:]
return self.invokeHTTPRequest("GET", urlString: "/calc", pathParameters: pathParameters, queryParameters: queryParameters, headerParameters: headerParameters, body: nil, responseClass: Empty.self) as! AWSTask<Empty>
}
I'm fairly certain this return type of Empty refers to the Empty model defined for the REST API as shown in the screenshot below. I think it's "empty" because the API doesn't alter the response from the Lambda function back to the Client. So, it's all pass-through. Indeed, the tutorial explains that the other models -- Output and Result -- are not used because it "relies on the passthrough behavior and does not use this model."
Any thoughts?
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 real big problem finding the right code which helps me to parse String to JSON and then send to external server. I'm using xCode 6.1, so some ways of parsing won't work for me, like SwiftyJSON.
On internet i only can find the way to send String , but not JSON, or if i found something it won't work.
I'm beginner in iOS and it would really help me if someone can explain me how to do it.
Thank you a lot.
If you have JSON String convert to NSData object.Check the data object before sending to an external server if data is valid JSON format or not by using NSJSONSerialization.I am giving sample code to how can check JSON Data valid or not.
suppose you String is like this,
let jsonString = "{\"device\":\"iPhone 6\",\"OS\":\"iOS 9\",\"name\":\"Apple\"}"
let data = jsonString.dataUsingEncoding(NSUTF8StringEncoding)
do {
let responseData = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments)
if responseData != nil { // valid JSON
//Now pass data object to server
}
} catch {
NSLog("ERROR when parse JSON")
}
The code works perfectly. The problem is that, after trying for a while, I cannot figure out how to make my program process a second link of different JSON data.
Here is my viewDidLoad where everything goes on:
override func viewDidLoad() {
super.viewDidLoad()
var err: NSError?
let urlPath: String = "https://na.api.pvp.net/api/lol/na/v1.4/summoner/by-name/" + searchFieldDataPassed + "?api_key=(removed my private api key for obvious reasons"
var url: NSURL = NSURL(string: urlPath)!
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithURL(url) { data, response, error in
// cast response as NSHTTPURLResponse and switch on statusCode if you like
if let httpResponse = response as? NSHTTPURLResponse { switch httpResponse.statusCode { case 200..<300: println("OK") default: println("Not OK") } }
// parse JSON using NSJSONSerialization if you've got data
if let jsonResult = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as? NSDictionary,
let include = jsonResult.objectForKey(self.searchFieldDataPassed) as? NSDictionary {
if let summLevel = include[ "summonerLevel" ] as? NSNumber {
dispatch_async(dispatch_get_main_queue()) {
self.summonerLevel.text = "\(summLevel.integerValue)"
println("summoner level: \(summLevel.integerValue)")
}
}
if let profIconId = include[ "profileIconId" ] as? NSNumber {
dispatch_async(dispatch_get_main_queue()) {
self.profileIconId.text = "\(profIconId.integerValue)"
println("profile icon id: \(profIconId.integerValue)")
}
}
if let idNum = include [ "id" ] as? NSNumber {
dispatch_async(dispatch_get_main_queue()) {
self.idNumber = idNum
println("id number: \(self.idNumber)")
}
}
}
// spawn off another network call here if you like
}
task.resume()
}
That is from my secondViewController where all the processing goes on for JSON and then is displayed.
Here is the JSON data that I'm processing (for the first JSON parsing):
{"soon2challenger":{"id":43993167,"name":"soon2challenger","profileIconId":844,"summonerLevel":30,"revisionDate":1435549418000}}
All of that works fine, now, I want to process this JSON data which actually takes the id from the first parsed JSON data and uses it in the link to process more data, which I would like to output, part of it, to the screen.
Second JSON data:
{"summonerId":43993167,"playerStatSummaries":[{"playerStatSummaryType":"AramUnranked5x5","wins":25,"modifyDate":1423007927000,"aggregatedStats":{"totalChampionKills":676,"totalTurretsKilled":20,"totalAssists":991}},{"playerStatSummaryType":"CAP5x5","wins":15,"modifyDate":1429065922000,"aggregatedStats":{"totalChampionKills":312,"totalMinionKills":4885,"totalTurretsKilled":31,"totalNeutralMinionsKilled":511,"totalAssists":216}},{"playerStatSummaryType":"CoopVsAI","wins":28,"modifyDate":1421882181000,"aggregatedStats":{"totalChampionKills":266,"totalMinionKills":2802,"totalTurretsKilled":50,"totalNeutralMinionsKilled":385,"totalAssists":164,"maxChampionsKilled":0,"averageNodeCapture":0,"averageNodeNeutralize":0,"averageTeamObjective":0,"averageTotalPlayerScore":49,"averageCombatPlayerScore":0,"averageObjectivePlayerScore":49,"averageNodeCaptureAssist":0,"averageNodeNeutralizeAssist":0,"maxNodeCapture":0,"maxNodeNeutralize":0,"maxTeamObjective":0,"maxTotalPlayerScore":49,"maxCombatPlayerScore":0,"maxObjectivePlayerScore":49,"maxNodeCaptureAssist":0,"maxNodeNeutralizeAssist":0,"totalNodeNeutralize":0,"totalNodeCapture":0,"averageChampionsKilled":0,"averageNumDeaths":0,"averageAssists":0,"maxAssists":0}},{"playerStatSummaryType":"CoopVsAI3x3","wins":15,"modifyDate":1421882181000,"aggregatedStats":{"totalChampionKills":140,"totalMinionKills":1114,"totalTurretsKilled":9,"totalNeutralMinionsKilled":449,"totalAssists":91}},{"playerStatSummaryType":"OdinUnranked","wins":1,"modifyDate":1421882181000,"aggregatedStats":{"totalChampionKills":31,"totalAssists":45,"maxChampionsKilled":10,"averageNodeCapture":4,"averageNodeNeutralize":4,"averageTeamObjective":0,"averageTotalPlayerScore":843,"averageCombatPlayerScore":268,"averageObjectivePlayerScore":575,"averageNodeCaptureAssist":3,"averageNodeNeutralizeAssist":1,"maxNodeCapture":6,"maxNodeNeutralize":7,"maxTeamObjective":2,"maxTotalPlayerScore":1468,"maxCombatPlayerScore":529,"maxObjectivePlayerScore":939,"maxNodeCaptureAssist":5,"maxNodeNeutralizeAssist":2,"totalNodeNeutralize":22,"totalNodeCapture":25,"averageChampionsKilled":5,"averageNumDeaths":5,"averageAssists":8,"maxAssists":19}},{"playerStatSummaryType":"RankedSolo5x5","wins":116,"losses":120,"modifyDate":1433630047000,"aggregatedStats":{"totalChampionKills":1699,"totalMinionKills":33431,"totalTurretsKilled":219,"totalNeutralMinionsKilled":6501,"totalAssists":1969}},{"playerStatSummaryType":"RankedTeam3x3","wins":0,"losses":0,"modifyDate":1377726216000,"aggregatedStats":{}},{"playerStatSummaryType":"RankedTeam5x5","wins":3,"losses":0,"modifyDate":1383784473000,"aggregatedStats":{"totalChampionKills":28,"totalMinionKills":636,"totalTurretsKilled":6,"totalNeutralMinionsKilled":101,"totalAssists":41}},{"playerStatSummaryType":"Unranked3x3","wins":9,"modifyDate":1421882181000,"aggregatedStats":{"totalChampionKills":90,"totalMinionKills":1427,"totalTurretsKilled":11,"totalNeutralMinionsKilled":428,"totalAssists":105}},{"playerStatSummaryType":"URF","wins":4,"modifyDate":1435024847000,"aggregatedStats":{"totalChampionKills":68,"totalMinionKills":642,"totalTurretsKilled":14,"totalNeutralMinionsKilled":182,"totalAssists":55}},{"playerStatSummaryType":"Unranked","wins":566,"modifyDate":1435549418000,"aggregatedStats":{"totalChampionKills":8419,"totalMinionKills":128213,"totalTurretsKilled":960,"totalNeutralMinionsKilled":26117,"totalAssists":7812}}]}
Heres the link of the second JSON data I want to parse (just adding it, could be useful, but not sure):
https://na.api.pvp.net/api/lol/na/v1.3/stats/by-summoner/43993167/summary?season=SEASON2015&api_key=(took-out-my-private-api-key-for-obvious-reasons)
The link doesn't work because I have to keep my api key private to myself, but the JSON data that it displays is right above the link, which is the what it would result if you were to use the link with the api key.
Just to restate, I would like to process the second part (above of this) of JSON data, but I do not understand how to process multiple links of JSON. I have the first JSON data parsed, but am unable to parse the second JSON data.
I believe Apple is deprecating NSURLConnection. Take a look at NSURLSession. Using it, you can pass in a completion block that takes three arguments: NSData?, NSURLResponse?, and NSError?. The data object contains the JSON you can pass into the JSON serializer. After that, if you need to make another network call, just call it from inside the completion block with another NSURLSession data task. Alamofire is a great framework, but sometimes you don't need everything it provides, and it adds complexity into your app that if something goes wrong or doesn't behave the way you intend/understand, you may not fully understand why. If you want to keep it simple and under your control, use NSURLSession.
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithURL(url) { data, response, error in
// cast response as NSHTTPURLResponse and switch on statusCode if you like
// parse JSON using NSJSONSerialization if you've got data
// spawn off another network call here if you like
}
task.resume() // or in Swift 2, task?.resume()
First, i would totally prefer using some common frameworks for http requests - expecially if youre new in swift. For example here with alamofire.
https://github.com/Alamofire/Alamofire
There is also a version with integrated SwiftyJSON, so you are able to parse JSON Responses very easily.
https://github.com/SwiftyJSON/Alamofire-SwiftyJSON
So if you want to make a request, use this:
Alamofire.request(.GET, "http://httpbin.org/get")
.responseJSON { (_, _, json, _) in
var json = JSON(json)
// get the id out (depends on your structure of JSON):
let id = json["id"].int
}
Now you are able to perform a second Request (with the same Code) - Read the Documentation, how to make different Requests (like with POST) and add Parameters.
If you want to use Segues, so you want to load more data from the ID in another ViewController, you can use Segues to push the data to a second ViewController, and Load the new Content from JSON when the new ViewController is initialised.
Check out this how to send data through segues:
Sending data with Segue with Swift
I have a makeRequest() method inside a UITableViewController with the following code:
func makeRequest() {
Alamofire.request(.GET, self.foursquareEndpointURL, parameters: [
//"VENUE_ID" : self.foursquareVenueID,
"client_id" : self.foursquareClientID,
"client_secret" : self.foursquareClientSecret,
"v" : "20140806"
])
.responseJSON(options: nil) { (_, _, data, error) -> Void in
if error != nil {
println(error?.localizedDescription)
} else if let data: AnyObject = data {
let jObj = JSON(data)
if let venue = jObj["response"]["venue"].dictionaryValue as [String: JSON]? {
self.responseitems = jObj
println("venue is: \(venue)")
}
dispatch_async(dispatch_get_main_queue()) {
self.tableView.reloadData() // Update UI
}
}
}
}
also keep in mind that I have a property var responseitems:JSON = []
println("venue is: \(venue)") prints a nice looking response to console, so I know that is working correctly...
I also have a custom UITableViewCell class with a bindData() method with the following code:
func bindData() {
println("VenueDetailHeaderCell data did set")
self.venueDetailTitleLabel.text = self.headerInfo?["name"].stringValue
let labelData = self.headerInfo?["name"].stringValue
println("labelData is: \(labelData)")
}
As you can see, I am attempting to set a UILabel's text to the ["name"].stringValue in the JSON response. However, when I println("labelData is: \(labelData)") I get console output of labelData is: Optional("") which is obviously empty.
Here's a screenshot of what I'm trying to grab
What am I doing wrong here and how can I grab the name of the venue and assign my UILabel to it?
UPDATE:
I tried the following code
let labelData = self.headerInfo?["name"].error
println("labelData is: \(labelData)")
And get a console output of: "Error Domain=SwiftyJSONErrorDomain Code=901 "Array[0] failure, It is not an array" UserInfo=0x7fd6d9f7dc10 {NSLocalizedDescription=Array[0] failure, It is not an array}" If that is of use to anyone. I am really confused here... Any ideas?
The problem is that the headerInfo value is an error JSON object, because you're trying to access a dictionary with an integer index.
Note that var responseitems:JSON = [] does not create an array object. SwiftyJSON has auto-assignment-constructors (I'm new to swift, so not sure what the correct swift terminology is)... see this initialiser in the SwiftyJSON.swift source code:
extension JSON: ArrayLiteralConvertible {
public init(arrayLiteral elements: AnyObject...) {
self.init(elements)
}
}
What this means is that when you do var responseitems:JSON = [] you are not creating an array, you are creating a JSON object that is constructed with an empty array using the above init method. Then when you do self.responseitems = jObj you are re-assigning that responseitems variable to a JSON object with a dictionary in it. Therefore self.responseitems[0] is invalid.
Also note that with SwiftyJSON, there is no such thing as an optional JSON object. I notice in your comment you say that you do var headerInfo:JSON? ... - it's not possible to have an optional JSON.
var headerInfo: JSON = nil
The above is possible - this uses another auto-initialiser that initialises a valid JSON object that represents the JSON null value.
So, how to fix it?
When you assign headerInfo do it like this:
let headerInfo = self.responseitems["response"]["venue"]
And now in bindData you can do:
self.venueDetailTitleLabel.text = self.headerInfo["name"].stringValue
Note that all of the above assumes Swift 1.2 and SwiftyJSON >= 2.2 - also after you've understood the above and corrected the issue, you will probably want to refactor the code a bit to reflect the corrected understanding of the data-model.
The way to parse is the next
element: JSONValue //Something with JSONValue
if let title = element["name"]?.string {
cell.title.text = title
}