In my Swift code I make a URLRequest to my node.js server:
URLSession.shared.dataTask(with: checkoutRequest, completionHandler: {
[weak self] (data: Data?, response: URLResponse?, error: Error?) in
guard let data = data,
let dataString = String(data: data, encoding: String.Encoding.utf8) else {
return
}
// Help me!!!
}).resume()
The node.js handles this request by processing a transaction through the Braintree Payments checkout API.
checkoutProcessor.processCheckout(amount, nonce, (error, result) => {
// Checkout callback
if (error) {
res.write(error.message)
res.end()
} else if (result) {
console.log(result)
res.write(JSON.stringify(result))
res.end()
}
})
As usual, if the API request fails (e.g., no signal) it returns an error but if the transaction goes through, it returns a result.
The type of the result, however, depends on whether the financial transaction fails or succeeds:
For example, the result for a successful transaction:
Object {transaction: Transaction, success: true}
result for failed transaction:
ErrorResponse {errors: ValidationErrorsCollection, params: Object, message: "Insufficient Funds", transaction: Transaction, success: false}
The dataString winds up looking like this:
{\"transaction\":{\"id\":\"m7mj3qd7\",\"status\":\"submitted_for_settlement\",\"type\":\"sale\",\"currencyIsoCode\":\"USD\",\"amount\":\"12.34\",\"merchantAccountId\":\"yourpianobar\",\"subMerchantAccountId\":null,\"masterMerchantAccountId\":null,\"orderId\":null,\"createdAt\":\"2018-09-19T03:30:27Z\",\"updatedAt\":\"2018-09-19T03:30:27Z\",\"customer\":{\"id\":\"622865439\",\"firstName\":\"Test\",\"lastName\":\"FromSwiftTest\"
which certainly resembles a JSON object but I can't seem to decode it with JSONDecoder, doing so fails. (JSONEncoder also fails)
Most solutions I see for Objectifying stringified JSON data into Swift involves writing a swift struct into which to plop all the JSON object's properties, but since this the data structure of the result is unknown on the swift end, I don't know what to do.
How do I get these objects into my swift code?
Note: I've also tried just sending res.send(result) in the node.js code but that doesn't really change anything.
This would do the trick for Swift 5:
if let data = dataString.data(using: String.Encoding.utf8) {
do {
if let dictionary = try JSONSerialization.jsonObject(with: data, options: []) as? [String:Any] {
// Use this dictionary
print(dictionary)
}
} catch _ {
// Do nothing
}
}
You can use JSONSerialization class on your data to convert it from data to Dictionary/Array based on your json response. The code can look something like below (based on my understanding) in swift 4
URLSession.shared.dataTask(with: checkoutRequest) { (data, response, error) in
guard let requestData = data, error == nil, let httpResponse = response as? HTTPURLResponse else {
// handle error
return
}
do {
if httpResponse.statusCode == 200 {
// success json
let jsonObject = try JSONSerialization.jsonObject(with: requestData, options: .allowFragments)
print(jsonObject) // jsonObject can be dictionary or Array. Typecast it based on your response
} else {
//error json
let jsonObject = try JSONSerialization.jsonObject(with: requestData, options: .allowFragments)
print(jsonObject) // jsonObject can be dictionary or Array. Typecast it based on your response
}
}
catch {
print(error.localizedDescription)
}
}.resume()
Related
I'm making an http post request within the XCTest framework in Xcode for a simple UI test for my app. Within the request, the response is returned. I can't access that response outside of the URLSession task, and I need to because it contains a JWT that must be decoded and used for another http post request.
I've tried researching how to do this, but it is hard to know the right path as I am a beginner in Swift. I've tried creating a new json object and assigning that response to it outside of the URLSession, but it just says that it can't find that response, it is outside of scope.
// make HTTP request
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print(error?.localizedDescription ?? "No data")
return
}
let responseJSON = try? JSONSerialization.jsonObject(with: data, options: [])
if let responseJSON = responseJSON as? [String: Any] {
print(responseJSON)
}
}
task.resume()
let response = responseJSON as! [String:Any]
The expected results are that I now have my response object outside of the http request and I can then decode it. The actual results is the error:
Use of unresolved identifier 'responseJSON'
The request your making is asynchronous. So when you run the line...
let response = responseJSON as! [String:Any]
the network request hasn't finished yet. So you would normally use a completion handler that will be called when the network returns
Here is an example playground:
//: Playground - noun: a place where people can play
import PlaygroundSupport
import UIKit
PlaygroundPage.current.needsIndefiniteExecution = true
func postSomeData(completion: #escaping ([String: Any]?, Error?) -> Void) {
// setup request
let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")
let request = URLRequest(url: url!)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print(error?.localizedDescription ?? "No data")
completion(nil, error)
}
let responseJSON = try? JSONSerialization.jsonObject(with: data, options: [])
if let responseJSON = responseJSON as? [String: Any] {
completion(responseJSON, nil)
}
}
task.resume()
}
postSomeData() { response, error in
print(response, error)
PlaygroundPage.current.finishExecution()
}
Output:
Optional(["id": 1, "title": delectus aut autem, "completed": 0, "userId": 1]) nil
I would also suggest that you use Codable for parsing and mapping the JSON response. Here is an intro to using Codable but there are lots of resources available online on the subject.
I'm trying to work with JSON data returned from a service. The JSON is, according to JSON validators, valid and is very simple:
[{"ID":"SDS-T589863","TotalRisk":0.2458,"TotalScore":641.032}]
However trying to parse it in my Swift 4 code it is mysteriously (to me at least) invalid. Here's my attempt to parse it:
// make the request
let task = session.dataTask(with: urlRequest) {
(data, response, error) in
// check for any errors
guard error == nil else {
print(error!)
return
}
// make sure we got data
guard let responseData = data else {
print("Error: did not receive data")
return
}
// this is fine:
guard let ddd = String(bytes: responseData, encoding: String.Encoding.utf8) else {
print("can't")
return
}
print(ddd) // prints [{"ID":"SDS-T589863","TotalRisk":0.2458,"TotalScore":641.032}] happily
do {
// cannot serialize
guard let risk = try JSONSerialization.jsonObject(with: responseData, options: [JSONSerialization.ReadingOptions.allowFragments])
as? [String: Any]
else {
print("error trying to convert data to JSON")
return
}
print(risk)
} catch {
print("error trying to convert data to JSON")
return
}
}
task.resume()
}
Assuming that I have no control over the JSON object or the format in which it is returned to me, is there a way to tell what is wrong with the JSON and perhaps format the response so that it can be serialized correctly?
You should cast your data to the [[String: Any]] type because you have array in response.
You are trying to cast to [String: Any], but you have an array of [String: Any] because your response enclosed in [] brackets.
Example:
let risk = try JSONSerialization.jsonObject(with: responseData, options: [JSONSerialization.ReadingOptions.allowFragments]) as? [[String: Any]]
Or if you want to get just only one [String: Any] object from response you can write:
let risk = (try JSONSerialization.jsonObject(with: responseData, options: [JSONSerialization.ReadingOptions.allowFragments]) as? [[String: Any]])?.first
Or if your object can be an array or not an array (but it sounds a little bit strange) you could try to cast to several possible types.
The response type is array of json objects so you have to cast it to [[String: Any]]. Since you are using Swift 4, you can use Decodable type which maps the model to the response.
let task = URLSession().dataTask(with: urlRequest) { (data, response, error) in
// check for any errors
guard error == nil else {
print(error!)
return
}
// make sure we got data
guard let responseData = data else {
print("Error: did not receive data")
return
}
do {
let decoder = JSONDecoder()
let riskArray = try decoder.decode([Risk].self, from: responseData)
print(riskArray)
} catch {
print("error trying to convert data to Model")
print(error.localizedDescription)
}
}
task.resume()
You can define your Model struct like
struct Risk: Decodable {
let id: String
let totalRisk: Double
let totalScore: Double
enum CodingKeys: String, CodingKey {
case id = "ID"
case totalRisk = "TotalRisk"
case totalScore = "TotalScore"
}
}
You can read more about Decodable protocol here
I'm converting a project from Obj-c to Swift 3 and I can't get it to read JSON responses from our web methods. As far as I can see, the code looks like a good conversion from it's Obj-c counterpart, but the JSONSerilaization is having trouble.
I would post the old Obj-c, but it's spread across several NSURLConnection delegate methods. I can post this if required?
Swift 3:
// Set up the URL request
var getString : String = "https://TheWebMethod"
guard let url = URL(string: getString) else {
print("Error: cannot create URL")
return
}
let urlRequest = URLRequest(url: url)
// set up the session
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
// make the request
let task = session.dataTask(with: urlRequest) {
(data, response, error) in
// check for any errors
guard error == nil else {
print("error calling GET on Method")
print(error)
return
}
// make sure we got data
guard let responseData = data else {
print("Error: did not receive data")
return
}
// parse the result as JSON, since that's what the API provides
do {
guard let result = try JSONSerialization.jsonObject(with: responseData, options: []) as? [String: AnyObject] else {
print("error trying to convert data to JSON")
return
}
print("The result is: " + result.description)
guard let resultTitle = result["title"] as? String else {
print("Could not get title from JSON")
return
}
print("The title is: " + resultTitle)
} catch {
print("error trying to convert data to JSON")
return
}
}
task.resume()
Example JSON output when run through browser:
[{"id":"3","Initials":"TL","FullName":"Tony Law","LoginName":"test","Password":"password","EmailAddress":"myemailaddress","MobileTelNo":"0123456789","SecToken":"Secret"}]
I am trying to access nested JSON results using swiftyJSON and Alamofire. My print value is nill and I believe I am not doing this correctly. What should my parameters be? I am trying to get the quote value located at http://quotes.rest/qod.json
func getAPI() {
Alamofire.request(.GET, "http://quotes.rest/qod.json", parameters: ["contents": "quotes"])
.responseJSON { response in
if let JSON = response.result.value {
print(JSON["quote"])
}
}
}
In your JSON quotes is an array so if you want to access quote of the first object you should do it by accessing first object:
func getAPI() {
Alamofire.request(.GET, "http://quotes.rest/qod.json", parameters: ["contents": "quotes"])
.responseJSON { response in
if let jsonValue = response.result.value {
let json = JSON(jsonValue)
if let quote = json["contents"]["quotes"][0]["quote"].string{
print(quote)
}
}
}
}
If the syntax of the json isn't correct, since it is fully printed anyway you should notice what's wrong.
func getAPI() {
Alamofire.request(.GET, "http://quotes.rest/qod.json", parameters: ["contents": "quotes"])
// JSON response
.responseJSON { response in switch response.result {
case .Failure(let error):
// got an error in getting the data, need to handle it
print("error calling GET, json response type :")
// print alamofire error code
let statusCode = error.code
print("error code json : \(statusCode)")
// print json response from server
if let data = response.data {
print("Response data: \(NSString(data: data, encoding: NSUTF8StringEncoding)!)")
}
// print http status code plus error string
print(NSHTTPURLResponse.localizedStringForStatusCode(statusCode))
if let httpResponse : NSHTTPURLResponse = response.response {
print("HTTP Response statusCode: \(httpResponse.statusCode)")
}
case .Success( _):
let statusCode = (response.response?.statusCode)!
print("status code json : \(statusCode)")
print("there is a response json")
//print(value)
// parse the result as JSON, since that's what the API provides and save datas as new user in coreData
guard let data = response.data else {
print("Error parsing response data")
return
}
let json = JSON(data: data)
// access first element of the array
if let postContent = json["contents"]["quotes"][0]["quote"].string{
// deal with json
}
}
}
So I want to send a request to a specific API which is supposed to return a JSON file.
I am using Alamofire in order to get the JSON object :
dataFromAPI : JSON
Alamofire.request(.GET, myURL).responseJSON { (_, _, data) -> Void in
dataFromAPI = JSON(data)
}
My problem is that data is an array of AnyObject and the JSON function needs an AnyObject type. How can I transform one into another or resolve the problem ?
Not sure if I got your question, but will try to provide you an example of how I do it.
Changed code to your case.
Alamofire.request(.GET, myURL)
.validate(statusCode: 200..<300)
.validate(contentType: ["application/json"])
.responseJSON { request, response, jsonResult in
switch jsonResult {
case .Success:
if let data = jsonResult.value as? AnyObject {
self.dataFromAPI = JSON(data)
}
case .Failure(_, let error):
print(error)
}
}
Normally I wouldn't do unwrapping to AnyObject, as it makes little sense.
I usually unwrap to [String: AnyObject] as I'm expecting Dictionary from my API, and then I attempt to convert it to my custom model class.
Correct me if I miss-understood the question. :)
Alamofire returns a Result<AnyObject> object. You should check if the result is a success or a failure before extracting the JSON:
Alamofire.request(.GET, myURL)
.responseJSON { request, response, result in
switch result {
case .Success(let JSON):
print("Success with JSON: \(JSON)")
case .Failure(let data, let error):
print("Request failed with error: \(error)")
if let data = data {
print("Response data: \(NSString(data: data, encoding: NSUTF8StringEncoding)!)")
}
}
}