How can I retrieve JSON data using NSURLSession in Swift?

Other Questions RapidAPI
1

I’m developing a weather app using Swift, but I’m having trouble obtaining the JSON information from the API response. Here is the alternative code I’ve tried:

import Foundation

let headers = [
    "api-host": "weather-zipcode-service.example.com",
    "api-key": "my_secret_key"
]

let requestURL = URL(string: "https://weather-zipcode-service.example.com/forecast?zipcode=90210")!
var request = URLRequest(url: requestURL)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let error = error {
        print("Error: \(error)")
    } else if let httpResponse = response as? HTTPURLResponse {
        print("Response code: \(httpResponse.statusCode)")
    }
}

task.resume()

Although this code executes without error, it only returns the response headers. What changes should I make to capture the full JSON data from the response? I’m still learning to work with APIs in Swift and would really appreciate your guidance.

2

hey ryan, try checking the ‘data’ object in your completion. if data exists, do a JSONSerialization.jsonObject(with: data) and catch errors. hope that helps, lmk if u need more info

3

You’re on the right track with your code, Ryan. To retrieve the JSON data, you need to handle the ‘data’ parameter in your completion handler. Here’s a modification to your existing code:

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let error = error {
        print("Error: \(error)")
        return
    }
    
    guard let data = data else {
        print("No data received")
        return
    }
    
    do {
        if let jsonResult = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any] {
            print(jsonResult)
            // Process your JSON data here
        }
    } catch {
        print("JSON parsing error: \(error)")
    }
}

task.resume()

This should parse the JSON data from the response. Remember to handle the data appropriately based on your API’s structure.

4

Hey Ryan, I’ve been in your shoes before. NSURLSession can be tricky at first. Here’s what worked for me:

Instead of using JSONSerialization, I found it easier to use Codable protocol. First, create a struct that matches your JSON structure. Then, use JSONDecoder to parse the data. Something like this:

struct WeatherData: Codable {
// Define your properties here
}

let decoder = JSONDecoder()

do {
let weatherData = try decoder.decode(WeatherData.self, from: data)
// Use weatherData here
} catch {
print(“Decoding error: (error)”)
}

This approach is more type-safe and less error-prone. It’s been a game-changer for me in handling API responses. Give it a shot and see if it simplifies things for you!