How to parse JSON in Swift using NSURLSession
Don't declare an AnyObject
type for your decoded object since you want it to be an NSDictionary
and you're performing a conversion to do this.
Also it's better to use zero options for NSJSONSerialization instead of random ones.
In my example I've also used a custom error type just for demonstration.
Note, if you're using a custom error type, you have to also include a generic catch
to be exhaustive (in this example, with a simple downcasting to NSError).
enum JSONError: String, ErrorType {
case NoData = "ERROR: no data"
case ConversionFailed = "ERROR: conversion from JSON failed"
}
func jsonParser() {
let urlPath = "http://headers.jsontest.com/"
guard let endpoint = NSURL(string: urlPath) else {
print("Error creating endpoint")
return
}
let request = NSMutableURLRequest(URL:endpoint)
NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) in
do {
guard let data = data else {
throw JSONError.NoData
}
guard let json = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? NSDictionary else {
throw JSONError.ConversionFailed
}
print(json)
} catch let error as JSONError {
print(error.rawValue)
} catch let error as NSError {
print(error.debugDescription)
}
}.resume()
}
The same with Swift 3.0.2:
enum JSONError: String, Error {
case NoData = "ERROR: no data"
case ConversionFailed = "ERROR: conversion from JSON failed"
}
func jsonParser() {
let urlPath = "http://headers.jsontest.com/"
guard let endpoint = URL(string: urlPath) else {
print("Error creating endpoint")
return
}
URLSession.shared.dataTask(with: endpoint) { (data, response, error) in
do {
guard let data = data else {
throw JSONError.NoData
}
guard let json = try JSONSerialization.jsonObject(with: data, options: []) as? NSDictionary else {
throw JSONError.ConversionFailed
}
print(json)
} catch let error as JSONError {
print(error.rawValue)
} catch let error as NSError {
print(error.debugDescription)
}
}.resume()
}
For Swift 4 Web service Call , Post Method using URLSession
func WebseviceCall(){
var request = URLRequest(url: URL(string: "YOUR_URL")!)
request.httpMethod = "POST"
let postString = "PARAMETERS"
request.httpBody = postString.data(using: .utf8)
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue("application/json", forHTTPHeaderField: "Accept")
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print("error=\(error)")
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(response)")
}
do {
if let convertedJsonIntoDict = try JSONSerialization.jsonObject(with: data, options: []) as? NSDictionary {
// Print out dictionary
print(convertedJsonIntoDict)
}
} catch let error as NSError {
print(error.localizedDescription)
}
}
task.resume()
}
Apple declare here.
func dataTaskWithRequest(request: NSURLRequest, completionHandler: (NSData?, NSURLResponse?, NSError?) -> Void) -> NSURLSessionDataTask
Fix it:
NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) -> Void in
// Your handle response here!
}
UPDATE:
func jsonParser() {
let urlPath = "http://headers.jsontest.com/"
let endpoint = NSURL(string: urlPath)
let request = NSMutableURLRequest(URL:endpoint!)
NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) -> Void in
print(error)
}.resume()
}
RESULT:
Optional(Error Domain=NSURLErrorDomain Code=-1022 "The resource could not be loaded because the App Transport Security policy requires the use of a secure connection." UserInfo={NSUnderlyingError=0x7f8873f148d0 {Error Domain=kCFErrorDomainCFNetwork Code=-1022 "(null)"}, NSErrorFailingURLStringKey=http://headers.jsontest.com/, NSErrorFailingURLKey=http://headers.jsontest.com/, NSLocalizedDescription=The resource could not be loaded because the App >Transport Security policy requires the use of a secure connection.})
Hope this helps!