How can I get my iOS app connected with api? - ios

Question

I am a beginner in iOS development. I was trying to use an api URl: https://www.arbeitnow.com/api/job-board-api in my job search iOS app. But nothing shows on my app. I tested the URL in POSTMAN and it returns json(but HTML in description part?). I wrote the code:
func getResults(completed: #escaping (Result<[Results], ErrorMessage>) -> Void) {
let urlString = "https://www.arbeitnow.com/api/job-board-api"
guard let url = URL(string: urlString) else {return}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
if let _ = error {
completed(.failure(.invalidData))
return
}
guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
completed(.failure(.invalidResponse))
return
}
guard let data = data else {
completed(.failure(.invalidData))
return
}
do {
let deconder = JSONDecoder()
deconder.keyDecodingStrategy = .convertFromSnakeCase
let results = try deconder.decode([Results].self, from: data)
completed(.success(results))
} catch {
completed(.failure(.invalidData))
}
}
task.resume()
}
struct Results: Codable {
let slug, companyName, title, resultsDescription: String
let remote: Bool
let url: String
let tags, jobTypes: [String]
let location: String
let createdAt: Int
enum CodingKeys: String, CodingKey {
case slug
case companyName = "company_name"
case title
case resultsDescription = "description"
case remote, url, tags
case jobTypes = "job_types"
case location
case createdAt = "created_at"
}
}
I used the code in HomeViewController:
override func viewDidLoad() {
super.viewDidLoad()
title = "Home"
collectionView.backgroundColor = UIColor(named: "backgroundMain")
collectionView.register(SearchViewCell.self, forCellWithReuseIdentifier: cellId)
setupSearchBar()
Service.shared.getResults() { [weak self] result in
switch result {
case .success(let results):
print(results)
self?.jobResults = results
DispatchQueue.main.async {
self?.collectionView.reloadData()
}
case .failure(let error):
print(error)
}
}
}
888
I don't know what is wrong with my code. Can anyone help? Thanks!

Answer 1

You are discarding all meaningful error information, which will make this hard to diagnose. If you get an Error object, you should return that:
enum WebServiceError: Error {
case httpError(Data, Int)
}
func getResults(completion: #escaping (Result<[Results], Error>) -> Void) {
let urlString = "https://www.arbeitnow.com/api/job-board-api"
guard let url = URL(string: urlString) else {
completion(.failure(URLError(.badURL)))
return
}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard
let data = data,
let response = response as? HTTPURLResponse,
error == nil
else {
completion(.failure(error ?? URLError(.badServerResponse)))
return
}
guard 200 ..< 300 ~= response.statusCode else {
completion(.failure(WebServiceError.httpError(data, response.statusCode)))
return
}
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let results = try decoder.decode([Results].self, from: data)
completion(.success(results.data))
} catch {
completion(.failure(error))
}
}
task.resume()
}
So, that will,
if there was a URLSession error, tell you what the error was;
if there was a non-2xx status code, tell you what the code was (and return the body of the response, too, in case you want to look at that); and
if there was a parsing error, tell you what the parsing error was.
Without something like this, that captures the salient error information, you are flying blind.
In this case, the error is that you are parsing for [Results], but the structure is a dictionary, whose key is data and whose value is a [Results]. You are missing an object for this dictionary that wraps the [Results].
struct ResponseObject: Decodable {
let data: [Posting]
let links: Links
let meta: Meta
}
struct Posting: Decodable {
let slug, companyName, title, description: String
let remote: Bool
let url: String
let tags, jobTypes: [String]
let location: String
let createdAt: Int
}
struct Links: Decodable {
let first: URL?
let last: URL?
let prev: URL?
let next: URL?
}
struct Meta: Decodable {
let currentPage: Int
let path: URL
let perPage: Int
let from: Int
let to: Int
let terms: String
let info: String
}
func getResults(completion: #escaping (Result<[Posting], Error>) -> Void) {
let urlString = "https://www.arbeitnow.com/api/job-board-api"
guard let url = URL(string: urlString) else {
completion(.failure(URLError(.badURL)))
return
}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard
let data = data,
let response = response as? HTTPURLResponse,
error == nil
else {
completion(.failure(error ?? URLError(.badServerResponse)))
return
}
guard 200 ..< 300 ~= response.statusCode else {
completion(.failure(WebServiceError.httpError(data, response.statusCode)))
return
}
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let results = try decoder.decode(ResponseObject.self, from: data)
completion(.success(results.data))
} catch {
completion(.failure(error))
}
}
task.resume()
}

Answer 2

Your model does not match the JSON you receive from the link you provided:
Using:
struct Root: Codable{
let data: [WorkData]
let links: Links
let meta: Meta
}
// MARK: - Links
struct Links: Codable {
let first: String
let last, prev: String?
let next: String
}
// MARK: - Meta
struct Meta: Codable {
let currentPage, from: Int
let path: String
let perPage, to: Int
let terms, info: String
enum CodingKeys: String, CodingKey {
case currentPage = "current_page"
case from, path
case perPage = "per_page"
case to, terms, info
}
}
struct WorkData: Codable {
let slug, companyName, title, payloadDescription: String
let remote: Bool
let url: String
let tags, jobTypes: [String]
let location: String
let createdAt: Int
enum CodingKeys: String, CodingKey {
case slug
case companyName = "company_name"
case title
case payloadDescription = "description"
case remote, url, tags
case jobTypes = "job_types"
case location
case createdAt = "created_at"
}
}
should solve the problem
Usage:
let root = JsonDecoder().decode(Root.self, from: data)
let firstCompany = root.data[0]
Edit to adress the comment:
This should work!
let results = try decoder.decode([Results].self, from: data)
is your code isn´t it?
instead use:
let root = JsonDecoder().decode(Root.self, from: data)
how could data be missing here?
After that you should either map the root object to your Result type to keep your Viewmodel and completion Handler the way they are now. Or change Viewmodel and completion Handler instead.