Hello everyone,

I am trying to learn a little about using URLSession and getting a JSON file and download it and decode it.

I keep getting an error telling me that the JSON is corrupted or bad, I have verified the the data is good and valid JSON so I'm not sure why.

If anyone could test this I would be greatful, I don't see what's wrong with the JSON

Here is the small project I've been working with to test with

import SwiftUI

struct ContentView: View {
    let url = URL(string: "https://github.com/tazmancoder/MyAppStoreApps/blob/main/AppleAppStoreApps.json")

    var body: some View {
        VStack {
            Image(systemName: "square.and.arrow.down")
                .imageScale(.large)
                .foregroundColor(.accentColor)
                .padding()

            Button {
                fetchDataAndDecode(from: url!)
            } label: {
                Text("Download My Apps")
            }
            .buttonStyle(.bordered)
        }
        .padding()
    }

    func fetchDataAndDecode(from url: URL) {
        Task {
            do {
                let appData = try await URLSession.shared.decode(AppData.self, from: url)
            } catch let DecodingError.keyNotFound(key, context) {
                fatalError("Failed to decode due to missing key '\(key.stringValue)' not found – \(context.debugDescription)")
            } catch let DecodingError.typeMismatch(_, context) {
                fatalError("Failed to decode due to type mismatch – \(context.debugDescription)")
            } catch let DecodingError.valueNotFound(type, context) {
                fatalError("Failed to decode due to missing \(type) value – \(context.debugDescription)")
            } catch DecodingError.dataCorrupted(_) {
                fatalError("Failed to decode because it appears to be invalid JSON")
            } catch {
                fatalError("Failed to decode \(url): \(error.localizedDescription)")
            }
        }
    }
}

My JSON Model

// MARK: - Welcome
struct AppData: Codable {
    let resultCount: Int
    let results: [Result]
}

// MARK: - Result
struct Result: Codable {
    let wrapperType: String
    let artistType: String?
    let artistName: String
    let artistID: Int
    let artistViewURL: String?
    let features, supportedDevices: [String]?
    let kind: String?
    let trackViewURL: String?
    let trackContentRating, minimumOSVersion, trackCensoredName: String?
    let languageCodesISO2A: [String]?
    let fileSizeBytes, formattedPrice, contentAdvisoryRating: String?
    let currentVersionReleaseDate: Date?
    let releaseNotes, primaryGenreName: String?
    let primaryGenreID: Int?
    let sellerName, description: String?
    let genreIDS: [String]?
    let bundleID: String?
    let isVppDeviceBasedLicensingEnabled: Bool?
    let trackID: Int?
    let trackName: String?
    let releaseDate: Date?
    let version, currency: String?
    let price: Double?
    let genres: [String]?
    let userRatingCount: Int?

    enum CodingKeys: String, CodingKey {
        case wrapperType, artistType, artistName
        case artistID = "artistId"
        case artistViewURL = "artistViewUrl"
        case features, supportedDevices, kind
        case trackViewURL = "trackViewUrl"
        case trackContentRating
        case minimumOSVersion = "minimumOsVersion"
        case trackCensoredName, languageCodesISO2A, fileSizeBytes, formattedPrice, contentAdvisoryRating, currentVersionReleaseDate, releaseNotes, primaryGenreName
        case primaryGenreID = "primaryGenreId"
        case sellerName, description
        case genreIDS = "genreIds"
        case bundleID = "bundleId"
        case isVppDeviceBasedLicensingEnabled
        case trackID = "trackId"
        case trackName, releaseDate, version, currency, price, genres, userRatingCount
    }
}

Extension on URLSession

extension URLSession {
    func decode<T: Decodable>(
        _ type: T.Type = T.self,
        from url: URL,
        keyDecodingStrategy: JSONDecoder.KeyDecodingStrategy = .useDefaultKeys,
        dataDecodingStrategy: JSONDecoder.DataDecodingStrategy = .deferredToData,
        dateDecodingStrategy: JSONDecoder.DateDecodingStrategy = .deferredToDate
    ) async throws -> T {
        print("URL: \(url)")
        let (data, _) = try await data(from: url)

        print("Data: \(data.description)")
        let decoder = JSONDecoder()
        decoder.keyDecodingStrategy = keyDecodingStrategy
        decoder.dataDecodingStrategy = dataDecodingStrategy
        decoder.dateDecodingStrategy = dateDecodingStrategy

        let decoded = try decoder.decode(T.self, from: data)

        return decoded
    }
}

Hi! Change your URL string to this

https://raw.githubusercontent.com/tazmancoder/MyAppStoreApps/main/AppleAppStoreApps.json

your link returns webpage but not json

Or you can go on to GitHub project > Settings > Pages > Select "Branch" and "Save". Then you will see https://YourName.github.io/MyAppStoreApps then you can add MyAppStoreApps.json to get https://YourName.github.io/MyAppStoreApps/MyAppStoreApps.json

Thanks @ygeras and @NigelGee for your suggestions. I do appreciate it. I was able to get the file to download by changing the link.

Sorry, It took me awhile to get back to ya'll. Been head deep into trying to figure out another issue.

Thanks again for the help,

Taz