I have a tableView that is being populated using JSON data. At this time anytime there is an update to the JSON the user needs to pull down to refresh the tableView and the new data will load.
Is it possible to have the data refresh in the background when the app is exited or completely not even open on the user's phone and send the user a local notification saying there is new data?
How can this be done? I am more focused on local notifications.
Example of how I am currently getting my app to read JSON:
private func fetchJSON() {
guard let url = URL(string: "https://example.com/example/example.php"),
let value = name.addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed)
else { return }
var request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, _, error in
guard let data = data else { return }
do {
self.structure = try JSONDecoder().decode([structure].self,from:data)
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
catch {
print(error)
}
}.resume()
}
An example of how the api looks like from the address example.com/example/example.php is the following:
[{"person":"Jackson","number":"1928192",
"position":"driver"},{"person":"Jeff","number":"293829","position":"driver"}]
Step 1 :- Store json in UserDefault or in CoreData
if you are using UserDefault i personally perfer PropertyListEncoder&Decoder.
Step 2 :- Enable Background Capability
Step 3 :- implement local notification code in you app.
Related
I have a List that is updated with a Fetch class, an ObservableObject. It has an init function. This is that Fetch class.
#Published private(set) var items: [ItemsResult] = []
init() {
let url = URL(string: "[redacted]")!
URLSession.shared.dataTask(with: url) {(data, response, error) in
do {
if let itemsData = data {
let decodedData = try JSONDecoder().decode([ItemsResult].self, from: itemsData)
DispatchQueue.global(qos: .utility).async {
DispatchQueue.main.async {
print("running task")
self.items = decodedData
}
}
print(self.items)
} else {
print("No data")
}
} catch {
print("Error: \(error)")
}
}.resume()
}
When the app is build, it correctly displays the data returned by the API and it matches the database. However when I tap / click on one in order to delete it, or use the textarea I've added to add a new item it doesn't update.
struct TickrApp: View {
#EnvironmentObject var fetch: Fetch
var body: some View {
NavigationView {
Form {
Section {
VStack(alignment: .center) {
Text("Welcome to Tickr")
}
}
Section {
List(fetch.items) { item in
CheckView(checked: item.done, title: item.content.replacingOccurrences(of:"_", with: " "))
}
}
AddItemView()
}.navigationBarTitle(Text("Tickr"))
}
}
}
The database is being updated as shown when I log the decodedData they respond, however in each I just call Fetch(). Requests are made the same in all three cases.
One of the calls, for text input.
func toggle() {
checked = !checked
let url = URL(string: "")!
var req = URLRequest(url: url)
req.httpMethod = "POST"
let task = URLSession.shared.dataTask(with: req) { data, response, error in
guard let _ = data,
let response = response as? HTTPURLResponse,
error == nil else {
print("error", error ?? "Unknown error")
return
}
guard (200 ... 299) ~= response.statusCode else {
print("statusCode should be 2xx, but is \(response.statusCode)")
print("response = \(response)")
return
}
}
task.resume()
Fetch()
In order to update the list visually I need to completely quit the app / rerun it in order to have the new and/or deleted items show correctly. No errors show about background publishing changes or anything.
It appears that you're trying to call Fetch() to refresh your data. There are two things that are going to be a problem with this:
You're calling it outside of the dataTask completion handler. That means that it may get called before the write finishes
Calling Fetch() just creates a new instance of Fetch, when what you really want to do is update the results on your existing instance.
I'm assuming that your first code snipped is from Fetch. I'd change it to look more like this:
class Fetch: ObservableObject {
#Published private(set) var items: [ItemsResult] = []
init() {
performFetch()
}
func performFetch() {
//your existing fetch code that was in `init`
}
}
Then, in your AddItemView and CheckView, make sure you have this line:
#EnvironmentObject var fetch: Fetch
This will ensure you're using the same instance of Fetch so your list will reflect the same collection of results.
Once you're done with an operation like toggle(), call self.fetch.performFetch() to update your results. So, your last code snippet would turn into something like this:
let task = URLSession.shared.dataTask(with: req) { data, response, error in
//guard statements to check for errors
self.fetch.performFetch() //perform your refresh on the *existing* `Fetch` instance
}
A bigger refactor would involve moving your async code (like toggle) to a view model, instead of doing any of it in a View code. Also, look into using the URLSession Publishers using Combine, since you're using SwiftUI: https://developer.apple.com/documentation/foundation/urlsession/processing_url_session_data_task_results_with_combine
I have an issue understanding the process in consuming REST api services with SWIFT, seems like i'm missing something simple, but yet important here.
this is the singleton DataManager class, I'm using to consume API with loadNews() method, as you can see it's simple, request method, getter and initializer that will load the data.
for loadNews() I use Alamofire to handle request, and SwiftyJSON to parse the response.
class DataManager{
static let shared = DataManager()
private var data:JSON = JSON()
private init(){
print("testprint1 \(self.data.count)")
loadNews() { response in
self.data = response
print("initprint \(self.data.count)")
print(self.data["response"]["results"].count)
print(self.data["response"]["results"][0]["id"].stringValue)
}
print("testprint2 \(self.data.count)")
}
func getNews() -> JSON {
return data
}
func loadNews(completion: #escaping (JSON) -> ()){
Alamofire.request("...")
.responseJSON{ response in
guard response.result.isSuccess,
let value = response.result.value else {
print("Error: \(String(describing: response.result.error))")
completion([])
return
}
let json = JSON(value)
completion(json)
}
}
}
issue that i'm facing is when i try to call the DataManager() instance in my ViewController, I'm not able to read data in the controller for some reason, here is the controller code (relevant one):
class SecondViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
let data1 = DataManager.shared.getNews()
print("qa \(data1.count)")
}
...
}
now what bothers me is - logic behind this should be simple, let data1 = DataManager.shared.getNews() - if i'm not wrong will (should) execute the following flow:
init()->loadNews()->getNews()
initialize method will call loadNews, loadNews will fetch data from API, fill the data array, and getNews is supposed to return the filled data array, but that flow doesn't seem correct then
console output
console output text
testprint1 0
testprint2 0
qa 0
initprint 1
50
commentisfree/2019/dec/07/lost-my-faith-in-tech-evangelism-john-naughton
so it seems like both prints within init() get executed before loadNews() method that is between them, as well as "qa0" print that is printing the size of the array in the ViewController.
now my question is, does anyone see a mistake here, is this happening because of long network query, or am I just missing something, because it seems to me that data is properly loaded and parsed, which is seen in last 2 lines of output, but i can't get it where i need it, like it dissapears. is my logic here wrong? if someone could help I would really appreciate it.
The Alamofire process works asynchronously, but you don't consider it, that's the mistake.
Change the code to
class DataManager{
static let shared = DataManager()
func loadNews(completion: #escaping (JSON) -> ()){
Alamofire.request("...")
.responseJSON{ response in
guard response.result.isSuccess,
let value = response.result.value else {
print("Error:", response.result.error)
completion([])
return
}
let json = JSON(value)
completion(json)
}
}
}
class SecondViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
DataManager.shared.loadNews() { response in
print("initprint \(response.count)")
print(response["response"]["results"].count)
print(response["response"]["results"][0]["id"].stringValue)
}
}
...
}
You have to get the data from the completion handler in SecondViewController
I have consuming OData from api url using swiftyJSON. Here api url is connected with VPN.
And api url looks like http://192.xxx.xx.xx:8000/sap/opu/odata/sap/Z_SRV/PRListSetSet?$format=json
When i run in simulator, i can able get data from odata api url but while running in device, no data received from odata api url.
Since no vpn is connected to mobile device. how can i hard code my VPN programmactically to receive data in mobile?
here is how i'm getting data from OData api url:
typealias ServiceResponse = (JSON,Error?) -> Void
class PrListApiManager: NSObject {
static let sharedInstance = PrListApiManager()
let baseURL = apiUrlConstant.prListOdataUrl
func getPrList(onCompletion:#escaping (JSON) -> Void) {
let route = baseURL
makeHTTPGetRequest(path: route) { (json: JSON, error: Error?) in
onCompletion(json as JSON)
}
}
// MARK: perform a GET Request
private func makeHTTPGetRequest(path: String, onCompletion: #escaping ServiceResponse) {
let user = ApiloginConstant.user
let password = ApiloginConstant.password
let loginString = "\(user):\(password)"
guard let loginData = loginString.data(using: String.Encoding.utf8) else {
return
}
let base64LoginString = loginData.base64EncodedString()
print("base 64 login :\(base64LoginString)")
let headers = ["Authorization": "Basic \(base64LoginString)"]
// using URL and request getting a json
let request = URLRequest(url: NSURL(string: path)! as URL)
let config = URLSessionConfiguration.default
config.httpAdditionalHeaders = headers
let session = URLSession.init(configuration: config)
session.dataTask(with: request) { (data:Data?, response: URLResponse?, error:Error?) in
if let jsonData = data { // if data has a data and success
do {
let json: JSON = try JSON(data: jsonData)
onCompletion(json,nil)
print("json data:\(json)")
}catch {// error
onCompletion(JSON(),error)
}
} else { // if the data is nil
onCompletion(JSON(),error)
}
}.resume()
}
Connecting to a VPN is probably not your best bet. If your app is intended for public release, this can be a massive security concern and may overload your servers. The reason behind this is because I believe you cannot route only some of the traffic through a VPN. Either everything from the device goes through, or nothing does.
If you really need a way to reach your servers, consider using a proxy that only exposes that specific service out to the internet.
If you still want to go the VPN route, here's an answer that explains how to set it up: https://stackoverflow.com/a/39183930/4663856
So, I'm trying to make a very simple watchOS app in XCode. It consists of a button, two labels and a separator between the two labels. It is a digital assistant app, and needs to interface with Dialogflow (https://dialogflow.com).
The button calls the presentTextInputController function, and I want to use that result as a query to my Dialogflow agent.
I need to make an HTTP request, which in JS would look more like this:
{
url:"https://api.api.ai/v1/query",
method:"post",
body:JSON.stringify({query:"userInput",lang:"en-US",sessionID:"yaydevdiner"}),
headers:{
contentType:"application/json; charset=utf-8",
Authorization:"Bearer <auth_token>"
}
}
The response is a JSON object, and I need to access the jsonObject["result"]["speech"] value as a String to use Label.setText()
Everything I've tried has given errors about type Any and other such things. I also haven't been able to do much debugging since the print output isn't showing up in XCode.
I must mention that I'm an extreme beginner to Swift, and I am not good at handling their types and casting and unpacking and things like that.
Could someone show me how I might handle this request and the subsequent processing of the JSON?
Here is my current code:
//HTTP Request
let parameters = [
"query":name![0] as? String,
"lang":"en-US",
"sessionID":"yaydevdiner"
];
//create the url with URL
let url = URL(string: "https://api.api.ai/v1/query")! //change the url
//create the session object
let session = URLSession.shared
//now create the URLRequest object using the url object
var request = URLRequest(url: url)
request.httpMethod = "POST" //set http method as POST
do {
request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted) // pass dictionary to nsdata object and set it as request body
} catch let error {
print(error.localizedDescription)
}
request.addValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
request.addValue("Bearer f786fef55008491fb8422cea2be85eb1", forHTTPHeaderField: "Authorization")
//create dataTask using the session object to send data to the server
let task = session.dataTask(with: request as URLRequest, completionHandler: { data, response, error in
guard error == nil else {
return
}
guard let data = data else {
return
}
do {
//create json object from data
if let json = try JSONSerialization.jsonObject (with: data, options: .mutableContainers) as? [String:Any] {
self.Response.setText(json["result"]["string"]);
}
} catch let error {
print(error.localizedDescription)
}
})
task.resume()
}
Response is a text label.
This code gives me an error saying I should have a question mark between
json["result"] and ["speech"]. When I do this, it gives me another error saying "Type Any has no subscript members".
Ok, I figured it out.
Because XCode automatically makes an iOS app with the watchOS app, I decided to try debugging in the iOS app until I got the HTTP request and JSON parsing right.
Inside the JSONSerialization if statement, I had to add another if statement:
if let result = responseJSON["result"] as? [String:Any]{
self.Response.setText(result!["speech"] as? String ?? "Network error Occurred")
}
Thanks for the help from vadian!
I retrieved values from Json, i print retrieved values order changed(position changed) every time. please check my below code once:
override func viewDidLoad() {
super.viewDidLoad()
var myIds = [104016, 104010, 104014, 104018, 104000, 104038, 104015, 104011, 104015, 104010, 104010, 104010, 104003, 104003, 104011]
for arr in 0 ..< myIds.count-1 {
let url = URL(string: "http://.........\(myIds[arr])")
print("myIds[\(arr)]:\(myIds[arr])")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil
{
print ("ERROR")
}
else
{
if let content = data
{
do
{
//Array
let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
var i = myJson["Job_title_name"]!
var ist = ""
// print("i=\(i)")
ist = String(describing: i!)
print("myIds[\(arr)]=\(ist)")
}
catch
{
}
}
}
}
task.resume()
}
}
**output:**
myIds[0]:104016
myIds[1]:104010
myIds[2]:104014
myIds[3]:104018
myIds[4]:104000
myIds[5]:104038
myIds[6]:104015
myIds[7]:104011
myIds[8]:104015
myIds[9]:104010
myIds[10]:104010
myIds[11]:104010
myIds[12]:104003
myIds[13]:104003
myIds[0]=WebLogic Admin
myIds[3]=OracleDevloper
myIds[2]=Node Js Developer
myIds[1]=Angular Developer
myIds[6]=HTML&CSS Developer
myIds[5]=Senior Manager
myIds[7]=CRM Developer
myIds[4]=Windows Manager
myIds[8]=HTML&CSS Developer
myIds[9]=Angular Developer
myIds[11]=Angular Developer
myIds[10]=Angular Developer
myIds[12]=java developer
myIds[13]=java developer
This output is changed every time, when stop and run the app. but i'm unable to find the problem. please check my code once.
Required output:
myIds[0]:104016
myIds[1]:104010
myIds[2]:104014
myIds[3]:104018
myIds[4]:104000
myIds[5]:104038
myIds[6]:104015
myIds[7]:104011
myIds[8]:104015
myIds[9]:104010
myIds[10]:104010
myIds[11]:104010
myIds[12]:104003
myIds[13]:104003
myIds[0]=WebLogic Admin
myIds[1]=Angular Developer
myIds[2]=Node Js Developer
myIds[3]=OracleDevloper
myIds[4]=Windows Manager
myIds[5]=Senior Manager
myIds[6]=HTML&CSS Developer
myIds[7]=CRM Developer
myIds[8]=HTML&CSS Developer
myIds[9]=Angular Developer
myIds[10]=Angular Developer
myIds[11]=Angular Developer
myIds[12]=java developer
myIds[13]=java developer
i want the above output. In the above code whats my mistake.
URLSession.shared.dataTask() usually call API in parallel execution so no matter if calling request order will same as response order.
If you want to call request and get response in same order then you should create NSOperation queue and make dependency on it.
Network requests run asynchronously, so this is the expected behaviour. The requests don't finish in the same order as they were started.
If you need your requests to run sequentially, you can run them using DispatchGroups, but this will lead to slower performance due to the fact that your asynchronous requests are executed sequentially instead of in parallel. A better solution is to store the results in a data structure, where you can identify the objects based on a unique identifier other than their index. For your current problem, the best solution is to store the results in a dictionary, where the key is the id and the value is the value from the network request.
Concurrent solution using a Dictionary to store the output values:
override func viewDidLoad() {
super.viewDidLoad()
var myIds = [104016, 104010, 104014, 104018, 104000, 104038, 104015, 104011, 104015, 104010, 104010, 104010, 104003, 104003, 104011]
var jobTitles = [Int:String]()
let group = DispatchGroup()
for arr in 0 ..< myIds.count-1 {
let url = URL(string: "http://.........\(myIds[arr])")
print("myIds[\(arr)]:\(myIds[arr])")
group.enter()
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil{
print ("ERROR")
} else {
if let content = data{
do {
guard let myJson = try JSONSerialization.jsonObject(with: content, options: []) as? [String:Any] else {return}
guard let jobTitle = myJson["Job_title_name"] as? String else {return}
jobTitles[myIds[arr]] = jobTitle
group.leave()
} catch {
}
}
}
}
task.resume()
}
}
}
group.notify(queue: DispatchQueue.main, execute: {
print(jobTitles)
})
Some general advice: don't force unwrap values from a server response and don't use String(describing:) to create a String. Use optional binding or default values to safely unwrap the optionals and either cast your values to String if they are String values or just use String(value) for values from which Strings can be directly initialized (such as Int).